pituitrin and Body-Weight

The treatment of central diabetes insipidus has not changed significantly in recent decades, and dDAVP and replacement of free water deficit remain the cornerstones of treatment. Oral dDAVP has replaced nasal dDAVP as a more reliable mode of treatment for chronic central diabetes insipidus. Hyponatraemia is a common side effect, occurring in one in four patients, and should be avoided by allowing a regular break from dDAVP to allow a resultant aquaresis. Hypernatraemia is less common, and typically occurs during hospitalization, when access to water is restricted, and in cases of adipsic DI. Management of adipsic DI can be challenging, and requires initial inpatient assessment to establish dose of dDAVP, daily fluid prescription, and eunatraemic weight which can guide day-to-day fluid targets in the long-term.

Topics: Body Weight; Deamino Arginine Vasopressin; Diabetes Insipidus; Diabetes Insipidus, Neurogenic; Humans; Hypernatremia; Hyponatremia; Neurophysins; Protein Precursors; Vasopressins

The neurohypophysial endocrine system is identified here as a potential target for therapeutic interventions toward improving obesity-related metabolic dysfunction, given its coinciding pleiotropic effects on psychological, neurological and metabolic systems that are disrupted in obesity.. Copeptin, the C-terminal portion of the precursor of arginine-vasopressin, is positively associated with body mass index and risk of type 2 diabetes. Plasma oxytocin is decreased in obesity and several other conditions of abnormal glucose homeostasis. Recent data also show non-classical tissues, such as myocytes, hepatocytes and β-cells, exhibit responses to oxytocin and vasopressin receptor binding that may contribute to alterations in metabolic function. The modulation of anorexigenic and orexigenic pathways appears to be the dominant mechanism underlying the effects of oxytocin and vasopressin on body weight regulation; however, there are apparent limitations associated with their use in direct pharmacological applications. A clearer picture of their wider physiological effects is needed before either system can be considered for therapeutic use.

Topics: Animals; Blood Glucose; Body Mass Index; Body Weight; Diabetes Mellitus, Type 2; Eating; Energy Metabolism; Gastrointestinal Microbiome; Glucose; Hepatocytes; Homeostasis; Humans; Insulin Resistance; Lipid Metabolism; Muscle Cells; Obesity; Oxytocin; Vasopressins

Due to the proximity of craniopharyngiomas to the hypothalamus and pituitary gland, most children and adolescents presenting with these tumors will exhibit significant endocrine dysfunction. After treatment, these impairments can become a major cause of morbidity and mortality.. The postoperative course of children undergoing surgery for craniopharyngioma is reviewed.. Even if hormone levels seem to be adequate in the short term after treatment, deficiencies may develop over years and need to be monitored closely.

Topics: Adrenocorticotropic Hormone; Body Weight; Child; Child, Preschool; Craniopharyngioma; Endocrine System; Endocrine System Diseases; Follicle Stimulating Hormone; Humans; Luteinizing Hormone; Neurophysins; Pituitary Neoplasms; Postoperative Complications; Protein Precursors; Thyrotropin; Vasopressins

This contribution summarizes the results of investigations of water-electrolyte metabolism and its hormonal regulation conducted in cosmonauts who performed long-term space flights (from 18 to 366 days) aboard the space stations Salyut and Mir and compares them with the results obtained during various NASA flights. The role of the kidneys in ion metabolism regulation was assessed by various water-salt load tests before and after flights. In addition, the results of a year-long space flight and of medical experiments performed during the 237- and 241-day missions by the physicians and cosmonaut-researchers Atkov and Polyakov are reviewed in detail. In spite of interindividual variations, metabolic, and endocrine studies during prolonged space flights showed a reduction in body mass, usually with a reduction in body water and electrolytes and considerable changes in blood hormone concentrations and urinary hormone excretion. These changes reflect the processes of extended adaptation to a new environment. It is likely that shifts in electrolyte metabolism in weightlessness are primarily due to metabolic changes that diminish the tissue ability for ion retention and to concomitant changes in the endocrine status. The postflight examinations revealed changes in fluid-electrolyte metabolism and in the function of the kidneys which indicated a hypohydration status and a stimulation of hormonal systems responsible for fluid-electrolyte homeostasis in order to readapt to the normal gravitation. Postflight decline in osmotic concentration of urine in cosmonauts was accompanied by an altered response to antidiuretic hormone and was probably caused by changes in the functional state of the kidneys. We conclude that detailed knowledge of the alterations in water-electrolyte metabolism and its hormonal regulation on different stages of space flight are important prerequisites for the development of countermeasures to space deconditioning and thus for increased human efficiency in space. In addition, these data contribute to an increase in our general knowledge on the regulation of kidney function.

Topics: Aerospace Medicine; Body Weight; Calcium; Catecholamines; Homeostasis; Humans; Kidney; Male; Natriuretic Agents; Renin-Angiotensin System; Vasopressins; Water-Electrolyte Balance

Topics: Animals; Arginine Vasopressin; Blood Pressure; Blood Volume; Body Fluid Compartments; Body Weight; Female; Hormones; Humans; Kidney Concentrating Ability; Osmolar Concentration; Pregnancy; Pseudopregnancy; Rats; Thirst; Vasopressins; Water-Electrolyte Balance

The premenstrual syndrome (PMS) has gained much attention in the past few years. Despite the many studies that have attempted to determine the underlying biochemical changes in the syndrome and the larger number of studies attempting to evaluate treatment, we are really no wiser about PMS now than when the syndrome was described originally. The literature has been plagued by uncontrolled therapeutic trials, poorly conducted biochemical and endocrinologic studies and enthusiastic but unsubstantiated anecdotes. This review cannot hope to provide the answers since the background information is not yet established. However, providing an overview of current and past theories of the etiology and treatment regimens should enable the clinician and researcher to place new ideas and publications in perspective and to avoid many of the pitfalls of previous studies.

Topics: Adult; Affective Symptoms; Body Water; Body Weight; Contraceptives, Oral; Diuretics; Endorphins; Female; Humans; Premenstrual Syndrome; Progesterone; Progesterone Congeners; Prolactin; Prostaglandins; Renin-Angiotensin System; Sodium; Vasopressins; Vitamins

The endogenous opiate system is involved in the regulation of numerous bodily functions, but the literature suggests that the effects of endogenous opioids differ among species and between animals and man. Naltrexone, a relatively pure opiate antagonist, appears to have significant effects on the secretion of the gonadotropins (luteinizing hormone and follicle-stimulating hormone), adrenocorticotropin (ACTH), cortisol, and probably catecholamines. Naltrexone appears to have minor or no effects on prolactin, the pituitary-thyroid axis, growth hormone, insulin, glucagon, vasopressin, and the gut hormones. Naltrexone also seems to reduce food intake and cause weight loss in humans. The dosages of opiate antagonist and the presence of other variables play a major role in the responses seen in various studies.

Topics: Adrenocorticotropic Hormone; Animals; Body Weight; Eating; Endocrine Glands; Female; Follicle Stimulating Hormone; Hormones; Humans; Hydrocortisone; Luteinizing Hormone; Male; Mice; Naloxone; Naltrexone; Rats; Vasopressins

Topics: Age Factors; Aged; Benzothiadiazines; Body Water; Body Weight; Diuretics; Female; Furosemide; Humans; Hyponatremia; Iatrogenic Disease; Inappropriate ADH Syndrome; Male; Middle Aged; Potassium; Prognosis; Risk; Sex Factors; Sodium; Sodium Chloride; Sodium Chloride Symporter Inhibitors; Vasopressins

A short survey is given over changes in water metabolism from early foetal life to infancy. The close connection between water metabolism and body composition is described as well as the changes taking place after birth. The impact of intrauterine malnutrition, delivery and postnatal nutrition is discussed.

Topics: Adipose Tissue; Amniotic Fluid; Body Composition; Body Fluid Compartments; Body Water; Body Weight; Delivery, Obstetric; Diuretics; Extracellular Space; Female; Fetus; Humans; Infant, Newborn; Kidney; Male; Maternal-Fetal Exchange; Placenta; Pregnancy; Vasopressins; Water Loss, Insensible

Topics: Adrenal Glands; Anorexia Nervosa; Behavior; Blood Glucose; Body Temperature Regulation; Body Water; Body Weight; Feeding Behavior; Female; Follicle Stimulating Hormone; Gonadotropin-Releasing Hormone; Growth Hormone; Humans; Hydrocortisone; Hypothalamus; Insulin; Luteinizing Hormone; Male; Pituitary Function Tests; Prolactin; Thyrotropin; Thyrotropin-Releasing Hormone; Vasopressins

Topics: Adrenergic alpha-Antagonists; Adrenergic beta-Antagonists; Animals; Blood Vessels; Body Weight; Catecholamines; Cats; Dogs; Electric Stimulation; Guinea Pigs; Haplorhini; Histamine; Humans; Mice; Muscle Contraction; Muscle, Smooth; Organ Size; Oxytocin; Parasympathetic Nervous System; Parasympathomimetics; Prostaglandins; Rabbits; Rats; Regional Blood Flow; Serotonin; Spleen; Sympathetic Nervous System; Vasopressins

Topics: Adrenalectomy; Angiotensin II; Animals; Blood Pressure; Body Weight; Catecholamines; Desoxycorticosterone; Female; Growth Hormone; Hippocampus; Hypertension; Hypophysectomy; Methylprednisolone; Norepinephrine; Rats; Reticular Formation; Sensory Deprivation; Sound; Tyramine; Vasopressins

Topics: Aldosterone; Body Fluids; Body Water; Body Weight; Calcium; Chlorides; Extracellular Space; Female; Humans; Kidney Glomerulus; Kinetics; Lymph; Male; Osmolar Concentration; Plasma; Potassium; Sodium; Vasopressins; Water-Electrolyte Balance

Topics: Body Weight; Dehydration; Diabetes Insipidus; Diagnosis, Differential; Humans; Hypertonic Solutions; Injections, Intramuscular; Injections, Intravenous; Isotonic Solutions; Nicotine; Polyuria; Smoking; Sodium Chloride; Sulfonylurea Compounds; Thirst; Vasopressins

Topics: Adrenal Cortex Hormones; Animals; Biopsy; Body Weight; Diet, Sodium-Restricted; Eclampsia; Edema; Female; Glomerulonephritis; Humans; Hypertension; Hypertension, Renal; Kidney; Kidney Diseases; Nephritis; Pre-Eclampsia; Pregnancy; Pregnancy Complications; Pyelonephritis; Sodium; Uric Acid; Vasopressins; Water-Electrolyte Balance

Topics: Aged; Aldosterone; Angiotensin II; Animals; Blood Pressure; Body Weight; Diet, Sodium-Restricted; Dogs; Endocrine Glands; Heart Atria; Heart Failure; Humans; Male; Middle Aged; Mitral Valve Insufficiency; Renal Veins; Renin; Sodium; Vasopressins; Water-Electrolyte Balance

Novel methods of acute weight loss practiced by combat sport athletes include "water loading," the consumption of large fluid volumes for several days prior to restriction. We examined claims that this technique increases total body water losses, while also assessing the risk of hyponatremia. Male athletes were separated into control (n = 10) and water loading (n = 11) groups and fed a standardized energy-matched diet for 6 days. Days 1-3 fluid intake was 40 and 100 ml/kg for control and water loading groups, respectively, with both groups consuming 15 ml/kg on Day 4 and following the same rehydration protocol on Days 5 and 6. We tracked body mass (BM), urine sodium, urine specific gravity and volume, training-related sweat losses and blood concentrations of renal hormones, and urea and electrolytes throughout. Physical performance was assessed preintervention and postintervention. Following fluid restriction, there were substantial differences between groups in the ratio of fluid input/output (39%, p < .01, effect size = 1.2) and BM loss (0.6% BM, p = .02, effect size = 0.82). Changes in urine specific gravity, urea and electrolytes, and renal hormones occurred over time (p < .05), with an interaction of time and intervention on blood sodium, potassium, chloride, urea, creatinine, urine specific gravity, and vasopressin (p < .05). Measurements of urea and electrolyte remained within reference ranges, and no differences in physical performance were detected over time or between groups. Water loading appears to be a safe and effective method of acute BM loss under the conditions of this study. Vasopressin-regulated changes in aquaporin channels may potentially partially explain the mechanism of increased body water loss with water loading.

Topics: Adult; Athletes; Blood Chemical Analysis; Body Composition; Body Water; Body Weight; Diet; Drinking; Electrolytes; Fluid Therapy; Humans; Male; Martial Arts; Urinalysis; Vasopressins; Water; Weight Loss; Wrestling; Young Adult

Arginine vasopressin (AVP) V(2) receptor antagonism is a new approach to the management of hyponatraemia in congestive heart failure (CHF). The aim of this study was to investigate the efficacy and safety of satavaptan, an oral AVP V(2)-receptor antagonist, in patients with dilutional hyponatraemia.. A total of 118 patients (90 with CHF) with dilutional hyponatraemia (serum sodium 115-132 mmol/L) were randomized to double-blind treatment with placebo or to 25 or 50 mg/day of satavaptan for 4 days, followed by non-comparative open-label satavaptan therapy for up to 343 days. The response rate (sodium ≥ 135 mmol/L and/or an increase in ≥ 5 mmol/L above baseline) was significantly higher with satavaptan 50 mg than with placebo (61.0 vs. 26.8%; P= 0.0035), with a trend towards significance with satavaptan 25 mg (48.6%, P= 0.0599). Median times to response were 3.30 and 2.79 days with satavaptan 25 and 50 mg/day, respectively, both shorter than placebo (>4 days; P= 0.0278 and P= 0.0004, respectively). Satavaptan therapy was effective in CHF patients, with response rates higher with both satavaptan 25 mg/day (53.6%) and 50 mg/day (57.1%) than with placebo (23.5%; P= 0.019 and P= 0.009, respectively). Sodium responses were maintained during open-label therapy after a temporary study drug discontinuation period. Higher rates of adverse events occurred with the 50 mg/day dose, including rapid correction of hyponatraemia.. In patients with dilutional hyponatraemia, V(2) receptor antagonism with satavaptan was effective in increasing serum sodium concentrations. The long-term open-label treatment results demonstrate sustained efficacy of satavaptan in maintaining normal sodium levels. Trial Registration clinicaltrials.gov Identifier: NCT00274326.

Topics: Adult; Aged; Antidiuretic Hormone Receptor Antagonists; Body Weight; Double-Blind Method; Female; Heart Failure; Humans; Hyponatremia; Kaplan-Meier Estimate; Male; Middle Aged; Morpholines; Sodium; Spiro Compounds; Treatment Outcome; Vasopressins; Young Adult

Increased vasopressin levels may be present in patient with chronic heart failure (HF) and contribute to pathophysiology through effects on the vasopressin V2 receptor. The presence of background diuretic therapy may confound evaluations of vasopressin receptor antagonists (VRA).. Eligible patients had HF (New York Heart Association Class II-III), systolic dysfunction (left ventricular ejection fraction ≤0.40) and signs of congestion (eg, edema, rales). At screening, patients were removed from baseline diuretic therapy and placed on a low-sodium diet (2 g/day). After a 2-day run-in period, 83 patients were randomized to placebo (n = 21), monotherapy with the vasopressin V2 receptor antagonist tolvaptan (TLV) 30 mg (n = 20), monotherapy with furosemide 80 mg (FURO, n = 22) or both TLV 30 mg and FURO 80 mg (n = 20) once daily for 7 days. Patients were on standard background therapy and not fluid-restricted throughout the study. A decrease in body weight of -1.37 ± 1.61, -0.54 ± 1.59, and -1.13 ± 1.49 kg was observed versus baseline for TLV, FURO, and TLV+FURO, respectively, at day 8. At the same point, the placebo group showed a body weight increase of +0.72 ± 2.42 kg versus baseline (P = .0006 for TLV versus placebo). Increases in urine volume from baseline were greater with TLV alone (2646 ± 1503 mL/24 hours) than with FURO (894 ± 853 mL/24 hours, P < .001), or PLC (423 ± 786 mL/24 hours, P < .001), and similar to TLV+FURO (2585 ± 2119 mL/24 hours). An increase in serum sodium within the normal range was also observed in TLV-treated patients (P < .02 versus placebo; P < .01 versus FURO). No changes in serum potassium, other laboratory values, or blood pressure were observed. TLV therapy was well tolerated.. In patients with HF and signs of volume overload, TLV monotherapy without concomitant loop diuretic therapy reduced body weight when compared to placebo without adverse changes in serum electrolytes, during a sodium restricted diet while on background medications including angiotensin-converting enzyme inhibitors and β-blockers.

Topics: Antidiuretic Hormone Receptor Antagonists; Benzazepines; Body Weight; Diuretics; Double-Blind Method; Drug Therapy, Combination; Female; Furosemide; Heart Failure, Systolic; Humans; Male; Middle Aged; Statistics as Topic; Stroke Volume; Tolvaptan; Vasopressins; Ventricular Function, Left

Evidence of the effect of dehydration on physiological responses to hypoxia is limited. The purpose of this study was to determine the effect of hypohydration severity on physiological, renal hormonal and psychological responses to acute hypoxia. Eight males completed intermittent walking tests under normobaric hypoxic conditions (FI O(2) = 0.13) after completing four separate hypohydration protocols, causing change in body mass of approximately 0% (EU), -1% (H1), -2% (H2) and -3% (H3). Physiological and psychological markers were monitored throughout the 125 min test. Fluid controlling hormones were measured pre and post exposure. Heart rate, core temperature, peripheral arterial oxygen saturation (SpO(2)), minute ventilation and urine osmolality were found to be significantly different between hydration conditions and correlated with Lake Louise Questionnaire score (LLQ) (P < 0.05). LLQ score increased with hypohydration severity above H2 (EU 1.3 +/- 1; H1 1.2 +/- 1; H2 2.7 +/- 2; H3 3.9 +/- 2) (P < 0.001). Antidiuretic hormone and aldosterone increased over the test, but were not different between hydration conditions (P < 0.05). Atrial natriuretic peptide showed no change over time, or with conditions. Therefore, renal hormones are not influenced by hypohydration severity during moderate intensity hypoxic exercise. Hypohydration less than -2% induces greater physiological strain during hypoxic exercise and may cause rise in symptoms such as, fatigue, headache, nausea and lightheadedness.

Topics: Adaptation, Physiological; Adaptation, Psychological; Adult; Aldosterone; Algorithms; Body Weight; Dehydration; Exercise; Heart Rate; Hormones; Humans; Kidney; Male; Oxygen; Vasopressins; Young Adult

To study the effects of microgravity on the mechanisms involved in the regulation of body hydrous status, total body water (TBW), plasma volume (PV), and its main regulating hormones (plasma renin, aldosterone, atrial natriuretic peptide (ANP), anti-diuretic hormone (ADH)) were determined, by isotopic dilution, Dill and Costill's formula, and radio-immunologic dosages, in 9 male subjects submitted to a 90-d head-down bed rest (HDBR). ADH was determined in 24 h urinary collection as well as osmolality, sodium, and potassium. Body mass decreased (-2.8 +/- 0.8 kg) as well as TBW(-7.2% +/- 0.9%, i.e., -2.6 +/- 0.7 kg) and PV (-4.7% +/- 1.8%). Renin and aldosterone were enhanced (+109.0% +/- 15.4% and +87.2% +/- 38.9%, respectively). Simultaneously, we observed a decrease in ANP (-33.2% +/- 20.4%). Other variables, including ADH, were not affected by HDBR. Body mass and TBW decrease (and consequently lean body mass) are associated with muscle atrophy. Renin, aldostrerone, and ANP modifications are well explained by the decrease in PV, which was not enough to induce ADH changes. It suggests that in man, the main regulatory factor for ADH secretion is osmolality, when PV is modestly and progressively decreased without arterial pressure modification, which was the case in the present protocol.

Topics: Adult; Aldosterone; Atrial Natriuretic Factor; Atrophy; Body Water; Body Weight; Head-Down Tilt; Hormones; Humans; Male; Osmolar Concentration; Plasma Volume; Radioisotope Dilution Technique; Renin-Angiotensin System; Vasopressins; Water-Electrolyte Balance; Weightlessness; Weightlessness Simulation

During exercise-heat stress, ad libitum drinking frequently fails to match sweat output, resulting in deleterious changes in hormonal, circulatory, thermoregulatory, and psychological status. This condition, known as voluntary dehydration, is largely based on perceived thirst. To examine the role of preexercise dehydration on thirst and drinking during exercise-heat stress, 10 healthy men (21 +/- 1 yr, 57 +/- 1 ml x kg(-1) x min(-1) maximal aerobic power) performed four randomized walking trials (90 min, 5.6 km/h, 5% grade) in the heat (33 degrees C, 56% relative humidity). Trials differed in preexercise hydration status [euhydrated (Eu) or hypohydrated to -3.8 +/- 0.2% baseline body weight (Hy)] and water intake during exercise [no water (NW) or water ad libitum (W)]. Blood samples taken preexercise and immediately postexercise were analyzed for hematocrit, hemoglobin, serum aldosterone, plasma osmolality (P(osm)), plasma vasopressin (P(AVP)), and plasma renin activity (PRA). Thirst was evaluated at similar times using a subjective nine-point scale. Subjects were thirstier before (6.65 +/- 0.65) and drank more during Hy+W (1.65 +/- 0.18 liters) than Eu+W (1.59 +/- 0.41 and 0.31 +/- 0.11 liters, respectively). Postexercise measures of P(osm) and P(AVP) were significantly greater during Hy+NW and plasma volume lower [Hy+NW = -5.5 +/- 1.4% vs. Hy+W = +1.0 +/- 2.5% (P = 0.059), Eu+NW = -0.7 +/- 0.6% (P < 0.05), Eu+W = +0.5 +/- 1.6% (P < 0.05)] than all other trials. Except for thirst and drinking, however, no Hy+W values differed from Eu+NW or Eu+W values. In conclusion, dehydration preceding low-intensity exercise in the heat magnifies thirst-driven drinking during exercise-heat stress. Such changes result in similar fluid regulatory hormonal responses and comparable modifications in plasma volume regardless of preexercise hydration state.

Topics: Adult; Aldosterone; Body Mass Index; Body Weight; Dehydration; Drinking; Exercise; Hematocrit; Hemodynamics; Hemoglobins; Hormones; Hot Temperature; Humans; Male; Osmolar Concentration; Renin; Thirst; Vasopressins; Walking

Although various exercise regimens are commonly used as countermeasures to reduce the cardiovascular deconditioning induced by microgravity, the underlying mechanisms are not well understood. In this study we aimed to test whether lower limb resistance exercise with flywheel technology can prevent the fluid homeostasis alterations induced by 90-day head-down tilt bed-rest (HDT), and thus improve orthostatic tolerance. Total body water (TBW, measured by isotope dilution) and plasma volume (PV, calculated from the haemoglobin and the haematocrit) were measured in a control group (Co, n=9) and a countermeasure group (CM, n=9). Simultaneously, plasma atrial natriuretic peptide (ANP), renin (AR), and aldosterone (Aldo), as well as urinary anti-diuretic hormone (ADH), were measured. Orthostatic tolerance was evaluated with a 10 min +80 degrees tilt-test the first day of recovery. After HDT, both groups showed a comparable decrease in orthostatic tolerance [8.2 (0.9) min, Co; 8.0 (0.7) min, CM], PV [-4.7 (1.8)%, Co; -6.2 (2.5)%, CM, P<0.05] and TBW [-6.3 (5.4)%, Co; -3.7 (2.1)%, CM, P<0.05]. AR [97.4 (22.0)%, Co; 117.3 (26.4)%, CM] and Aldo [111.3 (58.4)%, Co; 100.6 (52.0)%, CM] increased significantly in both groups but the countermeasures produced no noticeable effects [data are expressed as mean (SE)]. The drop in ANP was also similar in both groups [-42.0 (15.2)%, Co; -51.1 (27.7)% for the CM]. Surprisingly, urinary ADH declined similarly in both groups during the basal data control period [-25.3 (5.2)%, Co; -26.1 (9.6)%, CM) and was sustained at this level during the 90-day HDT. These results show that, under the conditions described, the flywheel exercise device failed to improve characteristic manifestations of cardiovascular deconditioning and suggest that more frequent and powerful exercise, associated with another device (e.g. LBNP) might be a better countermeasure.

Topics: Adult; Aldosterone; Bed Rest; Blood Cell Count; Blood Pressure; Blood Volume; Body Fluids; Body Mass Index; Body Water; Body Weight; Erythrocyte Count; Heart Rate; Hemoglobins; Humans; Hypotension, Orthostatic; Male; Physical Fitness; Plasma Volume; Renin; Rest; Urodynamics; Vasopressins; Water-Electrolyte Balance; Weightlessness Countermeasures

In 22 50-year-old men with long-standing, untreated essential hypertension of the low renin type, venous plasma vasopressin concentrations were about three times those of 15 matched normotensive control subjects (p less than 0.005). These patients also had increased arterial concentrations of noradrenaline and adrenaline (p less than 0.05) but there was no direct association between these two catecholamines and vasopressin. On the other hand, adrenergic beta-receptor blockade with oxprenolol reduced both blood pressure and plasma vasopressin (p less than 0.01) while venous plasma dopamine concentrations significantly increased. In addition, the hypertensives had highly significantly increased serum uric acid (p less than 0.001) that correlated positively with venous vasopressin concentrations (p less than 0.05). According to these data, patients with the volume-sustained low renin type of essential hypertension have increased plasma vasopressin concentrations that probably are inversely related to dopaminergic nervous activity. The data also indicate that increased plasma vasopressin correlates with serum uric acid, most probably through increased tubular reabsorption of this acid.

Topics: Atenolol; Blood Pressure; Body Weight; Catecholamines; Heart Rate; Humans; Hypertension; Male; Middle Aged; Oxprenolol; Renin; Uric Acid; Vasopressins

1. The effect of 3 days' treatment with indomethacin on the renal response to infused vasopressin was assessed in eight healthy volunteer subjects. 2. Indomethacin produced significant weight gain and an increase in serum potassium without a change in creatinine clearance. 3. Although indomethacin reduced maximum free water clearance in five subjects, the anti-diuresis produced by an incremental infusion of physiological amounts of vasopressin was no different whether indomethacin had been taken or not. 4. Indomethacin, in the dose we have used, is known to reduce prostaglandin production and we therefore conclude that endogenous prostaglandins do not inhibit the effect of physiological amounts of vasopressin on water clearance, which makes it unlikely that prostaglandins are important in the day-to-day modulation of response to vasopressin.

Topics: Adult; Body Weight; Creatinine; Diuresis; Humans; Indomethacin; Male; Osmolar Concentration; Potassium; Vasopressins; Water

In a randomized trial of pulsatile vs nonpulsatile cardiopulmonary bypass for coronary artery surgery, we studied hemodynamic and hormonal responses. Anesthesia did not produce a response but, from the time of the incision, cortisol and antidiuretic hormone levels and plasma renin activity all increased. Cortisol levels continued to rise after surgery, whereas the other began to fall. Systemic vascular resistance fell dramatically during cardiopulmonary bypass but rapidly rose after bypass with a reciprocal change in cardiac index. We did not see the changes ascribed to nonpulsatile bypass by others. There ws no difference between our pulsatile and nonpulsatile cases. High-flow cardiopulmonary bypass, vasodilating inhalation anesthesia and continuation of Inderal therapy may account for our results.

Topics: Body Temperature; Body Weight; Cardiopulmonary Bypass; Hemodynamics; Humans; Hydrocortisone; Hydrogen-Ion Concentration; Middle Aged; Osmolar Concentration; Potassium; Renin; Sodium; Urine; Vasopressins

Topics: Adolescent; Adult; Arginine; Blood Pressure; Body Weight; Child; Clinical Trials as Topic; Diabetes Insipidus; Diuresis; Drug Evaluation; Female; Humans; Injections, Intramuscular; Injections, Intravenous; Lysine; Male; Middle Aged; Osmolar Concentration; Pulse; Vasopressins

Topics: Adult; Aged; Anesthetics; Blood Urea Nitrogen; Body Weight; Creatinine; Halothane; Humans; Hypernatremia; Kidney Concentrating Ability; Kidney Diseases; Male; Methoxyflurane; Middle Aged; Osmolar Concentration; Polyuria; Postoperative Care; Prospective Studies; Sodium; Surgical Procedures, Operative; Time Factors; Uric Acid; Vasopressins; Water-Electrolyte Balance

Topics: Adult; Body Temperature; Body Weight; Clinical Trials as Topic; Diuresis; Hot Temperature; Humans; Natriuresis; Osmolar Concentration; Stress, Physiological; Sweat; Sweating; Urine; Vasopressins

Experimental allergic encephalomyelitis (EAE) is considered to be a useful animal model of human multiple sclerosis (MS). However, among the various symptoms of MS, the mechanisms contributing to inflammatory anorexia remain unclear. In the present study, we used an EAE rat model to examine changes in expression levels of hypothalamic feeding-related peptide genes and neuroendocrine responses such as the hypothalamo-neurohypophysial system and the hypothalamo-pituitary-adrenal (HPA) axis. The weight gain and cumulative food intake in EAE rats in the early days after immunization was significantly lower than that of the control group. The expression of orexigenic peptide genes Npy and Agrp were significantly increased, whereas the levels of anorectic peptide genes (Pomc and Cart) were significantly decreased in the hypothalamus of EAE rats. There was also a significant increase in the mRNA and plasma oxytocin (OXT) but not of arginine vasopressin (AVP) in the supraoptic and paraventricular nuclei (PVN) of EAE rats at days 12 and 18 after immunization. The expression of corticotropin-releasing hormone (Crh) and Avp was downregulated and upregulated, respectively, in the parvocellular division of the PVN at day 12 after immunization. The expression level of Pomc in the anterior pituitary significantly increased, accompanied by increased plasma corticosterone levels, at days 6, 12, and 18 after immunization. These results suggest that inflammatory anorexia in rat EAE may be caused by activation of the OXT-ergic pathway and HPA axis via changes in the expression of hypothalamic feeding-related peptides, including Avp but not Crh.

Topics: Animals; Arginine Vasopressin; Body Weight; Corticosterone; Eating; Encephalomyelitis, Autoimmune, Experimental; Hypothalamo-Hypophyseal System; Hypothalamus; In Situ Hybridization; Male; Neurophysins; Oxytocin; Pituitary-Adrenal System; Protein Precursors; Rats; Vasopressins

Nesfatin-1, processed from nucleobindin-2 (NUCB2), is a potent anorexigenic peptide being expressed in rodent hypothalamic nuclei and involved in the regulation of feeding behavior and body weight in animals. The present study aimed to investigate NUCB2/nesfatin-1 protein expression in the human hypothalamus as well as its correlation with body weight.. Sections of hypothalamus and adjacent cholinergic basal forebrain nuclei, including the nucleus basalis of Meynert (NBM) and the diagonal band of Broca (DBB), from 25 autopsy cases (17 males, 8 females; 8 lean, 9 overweight, 8 obese) were examined using immunohistochemistry and double immunofluorescence labeling.. Prominent NUCB2/nesfatin-1 immunoexpression was detected in supraoptic, paraventricular, and infundibular nuclei, lateral hypothalamic area (LHA)/perifornical region, and NBM/DBB. NUCB2/nesfatin-1 was found to extensively colocalize with (a) oxytocin and vasopressin in paraventricular and supraoptic nuclei, (b) melanin-concentrating hormone in the LHA, and (c) cocaine- and amphetamine-regulated transcript in infundibular and paraventricular nuclei and LHA. Interestingly, in the LHA, NUCB2/nesfatin-1 protein expression was significantly decreased in obese, compared with lean (p < 0.01) and overweight (p < 0.05) subjects.. The findings of the present study are suggestive of a potential role for NUCB2/nesfatin-1 as an integral regulator of food intake and energy homeostasis in the human hypothalamus. In the LHA, an appetite- and reward-related brain area, reduced NUCB2/nesfatin-1 immunoexpression may contribute to dysregulation of homeostatic and/or hedonic feeding behavior and obesity. NUCB2/nesfatin-1 localization in NBM/DBB might imply its participation in the neuronal circuitry controlling cognitive influences on food intake and give impetus towards unraveling additional biological actions of NUCB2/nesfatin-1 in human neuronal networks.

Topics: Adult; Aged; Aged, 80 and over; Body Weight; Case-Control Studies; Female; Humans; Hypothalamic Hormones; Hypothalamus; Male; Melanins; Middle Aged; Nerve Tissue Proteins; Nucleobindins; Obesity; Oxytocin; Pituitary Hormones; Vasopressins

Reciprocal interactions closely connect energy metabolism with circadian rhythmicity. Altered clockwork and circadian desynchronization are often linked with impaired energy regulation. Conversely, metabolic disturbances have been associated with altered autonomic and hormonal rhythms. The effects of high-energy (HE) diet on the master clock in the suprachiasmatic nuclei (SCN) remain unclear.This question was addressed in the Sand rat (Psammomys obesus), a non-insulin-dependent diabetes mellitus (NIDDM) animal model. The aim of this work was to determine whether enriched diet in Psammomys affects locomotor activity rhythm, as well as daily oscillations in the master clock of the SCN and in an extra-SCN brain oscillator, the piriform cortex. Sand rats were fed during 3 months with either low or HE diet. Vasoactive intestinal peptide (VIP), vasopressin (AVP) and CLOCK protein cycling were studied by immunohistochemistry and running wheel protocol was used for behavioral analysis. High energy feeding dietary triggered hyperinsulinemia, impaired insulin/glucose ratio and disruption in pancreatic hormonal rhythms. Circadian disturbances in hyper-insulinemic animals include a lengthened rest/activity rhythm in constant darkness, as well as disappearance of daily rhythmicity of VIP, AVP and the circadian transcription factor CLOCK within the suprachiasmatic clock. In addition, daily rhythmicity of VIP and CLOCK was abolished by HE diet in a secondary brain oscillator, the piriform cortex. Our findings highlight a major impact of diabetogenic diet on central and peripheral rhythmicity. The Psammomys model will be instrumental to better understand the functional links between circadian clocks, glucose intolerance and insulin resistance state.

Topics: Animals; Biological Clocks; Body Weight; Brain; CLOCK Proteins; Diet; Dietary Fats; Dietary Fiber; Eating; Gene Expression Regulation; Gerbillinae; Insulin Resistance; Somatostatin; Vasoactive Intestinal Peptide; Vasopressins

Recurrent dehydration and heat stress cause chronic kidney damage in experimental animals. The injury is exacerbated by rehydration with fructose-containing beverages. Fructose may amplify dehydration-induced injury by directly stimulating vasopressin release and also by acting as a substrate for the aldose reductase-fructokinase pathway, as both of these systems are active during dehydration. The role of vasopressin in heat stress associated injury has not to date been explored. Here we show that the amplification of renal damage mediated by fructose in thermal dehydration is mediated by vasopressin. Fructose rehydration markedly enhanced vasopressin (copeptin) levels and activation of the aldose reductase-fructokinase pathway in the kidney. Moreover, the amplification of the renal functional changes (decreased creatinine clearance and tubular injury with systemic inflammation, renal oxidative stress, and mitochondrial dysfunction) were prevented by the blockade of V1a and V2 vasopressin receptors with conivaptan. On the other hand, there are also other operative mechanisms when water is used as rehydration fluid that produce milder renal damage that is not fully corrected by vasopressin blockade. Therefore, we clearly showed evidence of the cross-talk between fructose, even at small doses, and vasopressin that interact to amplify the renal damage induced by dehydration. These data may be relevant for heat stress nephropathy as well as for other renal pathologies due to the current generalized consumption of fructose and deficient hydration habits.

Topics: Animals; Blood Pressure; Body Weight; Fructose; Hemodynamics; Immunohistochemistry; Kidney; Male; Oxidative Stress; Rats; Receptors, Vasopressin; Renal Insufficiency, Chronic; Vasopressins

Early-life stress induces endocrine and metabolic alterations that increase food intake and overweight in adulthood. The stress response activates the corticotropin-releasing hormone (CRH) and urocortins' (Ucns) system in the hypothalamic paraventricular nucleus (PVN). These peptides induce anorexic effects through CRH-R2 receptor activation; however, chronic stressed animals develop hyperphagia despite of high PVN CRH expression. We analyzed this paradoxical behavior in adult rats subjected to maternal separation (MS) for 180min/daily during post-natal days 2-14, evaluating their body weight gain, food intake, serum corticosterone and vasopressin concentrations, PVN mRNA expression of CRH-R1, CRH-R2, CRH, Ucn2, Ucn3, vasopressin and CRH-R2 protein levels. MS adults increased their feeding, weight gain as well as circulating corticosterone and vasopressin levels, evincing chronic hyperactivity of the stress system. MS induced higher PVN CRH, Ucn2 and CRH-R2 mRNA expression and protein levels of CRH-R2 showed a tendency to decrease in the cellular membrane fraction. An intra-PVN injection of the CRH-R2 antagonist antisauvagine-30 in control adults increased receptor's mRNA expression, mimicking the observed PVN receptor's up-regulation of early-life MS adults. An injection of Ucn-2 directly into the PVN reduced food intake and increased PVN pCREB/CREB ratio in control animals; in contrast, Ucn-2 was unable to reduce food intake and enhance phosphorylated-CREB levels in PVN of MS rats. In conclusion, the chronic hyperactivity of the stress axis and PVN CRH-R2 resistance to Ucn2 effects, supported impaired receptor functionality in MS animals, probably due to its chronic stimulation by CRH or Ucn2, induced by early-life stress.

Topics: Animals; Body Weight; Corticosterone; Eating; Hyperphagia; Maternal Deprivation; Paraventricular Hypothalamic Nucleus; Rats; Rats, Wistar; Receptors, Corticotropin-Releasing Hormone; Urocortins; Vasopressins

The neuropeptides oxytocin and vasopressin have been implicated in exercise, as well as monogamy and parental behavior. In this study, we compared behavioral and neuroendocrine effects of access to an exercise wheel vs. the sedentary state typical in lab animal housing. Male prairie voles (Microtus ochrogaster) were studied because of their extensive repertoire of social behaviors including pair bond formation and biparental care, which are influenced by oxytocin and vasopressin. Subjects in one group had access to a running wheel in their cage (wheel), and voluntarily ran approximately 1.5 km/day for six weeks; these animals were compared to males in standard housing conditions (n=10/group). Males allowed to exercise formed partner preferences significantly faster than controls and exhibited fewer oxytocin neurons, as measured by immunohistochemistry in the bed nucleus of the stria terminalis. We observed no differences in terms of anxiety-related behavior, or alloparental responsiveness. Males with a running wheel equipped cage gained more total body weight, and by the end of the six weeks were found to have less subcutaneous fat and larger testes as a percentage of bodyweight. The changes to gonadal regulation and pair-bonding behavior associated with voluntary exercise are discussed in terms of their possible relevance to the natural history of this species.

Topics: Animals; Arvicolinae; Body Weight; Male; Motor Activity; Neurons; Oxytocin; Pair Bond; Physical Conditioning, Animal; Septal Nuclei; Subcutaneous Fat; Testis; Vasopressins

Fixed-dose vasopressin is an adjunctive therapy to norepinephrine (NE) to raise mean arterial pressure (MAP) and decrease NE requirements in patients with septic shock. It is unknown if weight affects hemodynamic response to vasopressin or if a weight-based vasopressin strategy is superior to fixed dosing.. The primary objective was to evaluate effect of body weight on response to vasopressin as measured by change in MAP 1 hour post-vasopressin initiation.. A single-center, retrospective study was performed in patients with septic shock. Baseline characteristics, catecholamine and vasopressin requirement, response to therapy, and adverse events were collected.. Forty patients were included who received a fixed-dose vasopressin in addition to catecholamine infusions. No correlation was found in the primary outcome of change in MAP at 1 hour after vasopressin initiation compared with vasopressin dose relative to patient weight or body mass index (BMI). Change in MAP at 6 and 12 hours was not significant. In the obese population (n = 9), there was a significant negative correlation between BMI and change in MAP at 6 hours (correlation coefficient r = -0.951; P = 0.0009). Linear regression analysis confirmed that vasopressin dose relative toweight was independently associated with change in MAP at 1, 6, and 12 hours, whereas changes in NE dosing were not.. Increasing weight-based dosing of vasopressin did not correlate with change in MAP when used with catecholamine vasopressors in septic shock. However, fixed-dose vasopressin may not be sufficient in obese septic shock patients with a BMI ≥30 kg/m(2).

Topics: Arterial Pressure; Body Mass Index; Body Weight; Dose-Response Relationship, Drug; Female; Hemodynamics; Humans; Infusions, Intravenous; Male; Middle Aged; Norepinephrine; Obesity; Regression Analysis; Retrospective Studies; Shock, Septic; Vasoconstrictor Agents; Vasopressins

A disturbance of sensorimotor gating measured by prepulse inhibition of acoustic startle (PPI) is one of the best tests of the schizophrenia-like behavior. Vasopressin was implicated in the development of schizophrenia; therefore, the naturally occurring vasopressin-deficient Brattleboro rat has been suggested to be a reliable non-pharmacological animal model. However, previous studies focusing on PPI deficit did not use proper control and despite clear gender differences in the development of the disorder, the effect of gender has been mostly neglected.. First, we compared the "noise" and "tone" type prepulse at 73-77-81 dB intensity during the light or dark phase using small (~150 g) or big (~500 g) Wistar rats. The test parameters were validated by a pharmacological schizophrenia model (30 mg/kg ketamine i.p.). Than male, female, and lactating vasopressin-deficient animals were compared with +/+ ones.. We established that the prepulse "noise" type is not optimal for PPI testing. The cycle of the day as well as the body weight had no effect on PPI. Even if we compared vasopressin-deficient animals with their closely related +/+ controls, the PPI deficiency was visible with more pronounced effect at 77 dB prepulse intensity similarly to pharmacological schizophrenia model. Despite our expectation, the gender as well as lactation had no effect on the vasopressin-deficiency induced PPI deficit.. The present data confirmed and extended our previous studies that vasopressin-deficient rat is a good model of schizophrenia. It seems that female as well as lactating Brattleboro rats are useful tools for testing putative novel antipsychotics in line with special attention required for schizophrenic women.

Topics: Animals; Body Weight; Circadian Rhythm; Female; Male; Prepulse Inhibition; Rats; Rats, Brattleboro; Reflex, Startle; Sex Factors; Vasopressins

Parent-offspring interactions early in life can permanently shape the developmental path of those offspring. Manipulation of maternal care has long been used to alter the early-life environment of infants and impacts their later social behavior, aggression, and physiology. More recently, naturally occurring variation in maternal licking and grooming behavior has been shown to result in differences in social behavior and stress physiology in adult offspring. We have developed a model of natural variation in biparental care in the prairie vole (Microtus ochrogaster) and have demonstrated an association between the amount of early care received and later social behavior. In this study, we investigate the relationship between early life care and later aggression and neuroendocrine responses following chronic social isolation. Male and female offspring were reared by their high-contact (HC) or low-contact (LC) parents, then housed for 4 weeks post-weaning in social isolation. After 4 weeks, half of these offspring underwent an intrasexual aggression test. Brains and plasma were collected to measure corticotropin-releasing hormone (CRH) and vasopressin (AVP) immunoreactivity and plasma corticosterone (CORT). Male offspring of LC parents engaged in more aggressive behavior in the intrasexual aggression test compared to HC males. Female offspring of HC parents had higher plasma CORT levels after chronic social isolation and increases in the number and density of AVP-immunopositive cells in the supraoptic nucleus following an intrasexual aggression test. These findings show that the impact of early life biparental care on behavior and HPA activity following a social stressor is both sex-dependent and early experience-specific.

Topics: Aggression; Animals; Arvicolinae; Body Weight; Chronic Disease; Corticosterone; Corticotropin-Releasing Hormone; Female; Male; Maternal Behavior; Paternal Behavior; Random Allocation; Sex Characteristics; Social Isolation; Stress, Psychological; Supraoptic Nucleus; Vasopressins

Social relationships are essential for many fundamental aspects of life while bond disruption can be detrimental to mental and physical health. Male prairie voles form enduring social bonds with their female partners, allowing the evaluation of partner loss on behavior, physiology, and neurochemistry. Males were evaluated for partner preference formation induced by 24h of mating, and half were separated from their partner for 4 wk. In Experiment 1, partner loss significantly increased anxiety-like behaviors in the elevated plus maze and light-dark box tests and marginally increased depressive-like behaviors in the forced swim test. In addition, while intruder-directed aggression is common in pair bonded prairie voles, separated males were affiliative and lacked aggression toward an unfamiliar female and an intruding male conspecific. Partner loss increased the density of oxytocin-immunoreactivity (-ir), vasopressin-ir, and corticotrophin-releasing hormone-ir cells in the paraventricular nucleus of the hypothalamus and oxytocin-ir cells in the supraoptic nucleus. Tyrosine hydroxylase-ir was not affected. In Experiment 2, partner preference was observed after 2 wk of partner loss but eliminated after 4 wk partner loss. Body weight gain and plasma corticosterone concentrations were elevated throughout the 4 wk. No effects were observed for plasma oxytocin or vasopressin. Together, partner loss elicits anxiety-like and depression-like behaviors, disrupts bond-related behaviors, and alters neuropeptide systems that regulate such behaviors. Thus, partner loss in male prairie voles may provide a model to better understand the behavior, pathology, and neurobiology underlying partner loss and grief.

Topics: Adaptation, Ocular; Aggression; Animals; Arginine Vasopressin; Arvicolinae; Body Weight; Brain; Corticosterone; Corticotropin-Releasing Hormone; Male; Maze Learning; Neurochemistry; Oxytocin; Pair Bond; Social Isolation; Stress, Psychological; Swimming; Time Factors; Tyrosine 3-Monooxygenase; Vasopressins

To determine the population pharmacokinetics of unbound hydrocortisone in critically ill neonates and infants receiving IV hydrocortisone for treatment of vasopressor-resistant hypotension and to identify patient-specific sources of pharmacokinetic variability.. Prospective observational cohort study.. Level 3 neonatal ICU.. Sixty-two critically ill neonates and infants receiving IV hydrocortisone as part of standard of care for the treatment of vasopressor-resistant hypotension: median gestational age 28 weeks (range, 23-41), median weight 1.2 kg (range, 0.5-4.4), and 29 females.. None.. Unbound baseline cortisol and postdose hydrocortisone concentrations measured from blood samples being drawn for routine laboratory tests. A one-compartment model best described the data. Allometric weight and postmenstrual age were significant covariates on unbound hydrocortisone clearance and volume of distribution. Final population estimates for clearance, volume of distribution, and baseline cortisol concentration were 20.2 L/hr, 244 L, and 1.37 ng/mL, respectively. Using the median weight and postmenstrual age of our subjects (i.e., 1.2 kg and 28 wk) in the final model, the typical unbound hydrocortisone clearance and volume of distribution were 1.0 L/hr and 4.2 L, respectively. The typical half-life for unbound hydrocortisone was 2.9 hours. A sharp and continuous increase in unbound hydrocortisone clearance was observed at 35 weeks postmenstrual age.. We report the first pharmacokinetic data for unbound hydrocortisone, the pharmacologically active moiety, in critically ill neonates and infants with vasopressor-resistant hypotension. Unbound hydrocortisone clearance increased with body weight and was faster in children with an older postmenstrual age. Unbound hydrocortisone clearance increased sharply at 35 weeks postmenstrual age and continued to mature thereafter. This study lays the groundwork for evaluating unbound hydrocortisone exposure-response relationships and drawing definitive conclusions about the dosing of IV hydrocortisone in critically ill neonates and infants with vasopressor-resistant hypotension.

Topics: Blood Pressure; Body Weight; Critical Illness; Drug Resistance; Female; Gestational Age; Half-Life; Hormones; Humans; Hydrocortisone; Hypotension; Infant; Infant, Newborn; Male; Prospective Studies; Vasopressins

We tested the effects of photoperiod, water and food availability on body mass, reproductive status and arginine vasopressin receptor 1A (Avpr1a) mRNA expression in males of desert-adapted golden spiny mice, Acomys russatus. In Experiment 1, males were acclimated to short-day (SD; 8 h:16 h light:dark) or long-day (LD; 16 h:8 h light:dark) photoperiods with either saline (control) or vasopressin treatment for 3 weeks. The results of this experiment revealed that under control conditions, SD mice increased body mass by ~5% while LD mice decreased it by ~4%. SD photoperiod had no effect on reproductive status and leptin levels, whereas LD males increased testes mass and serum testosterone, but the photoperiod had no effect on leptin levels. Vasopressin administration decreased LD-induced reproductive enhancement. Because no consistent effect of SD treatment was found on reproductive status, Experiment 2 was carried out only on LD-acclimated males kept under 75% food restriction (decrease from ad libitum) with saline or leptin treatment. Body mass, testes mass, serum testosterone, leptin concentrations and Avpr1a mRNA expression were measured. Food restriction remarkably decreased body mass, with a more potent effect in leptin-treated males, showing enhanced reproductive status and a significant increase in serum leptin compared with controls. Avpr1a expression was significantly upregulated in LD, vasopressin-treated and food-restricted males, with higher levels in the hypothalamus compared with the testes. We conclude that in A. russatus, LD photoperiod interacts with water and food availability to advance reproductive responses. Avpr1a is suggested to integrate nutritional and osmotic signals to optimize reproduction by modulating reproductive and energetic neuroendocrine axes at the central level. The interaction between photoperiod and other environmental cues is of an adaptive value to desert-adapted small rodents for timing reproduction in unpredictable ecosystems such as extreme deserts.

Topics: Animals; Body Weight; Food Deprivation; Gene Expression Regulation; Leptin; Male; Models, Biological; Murinae; Organ Size; Photoperiod; Receptors, Vasopressin; Reproduction; RNA, Messenger; Testosterone; Vasopressins

Vasopressors used for the management of septic shock are often dosed according to body weight. Use of vasopressin for physiologic replacement in patients with septic shock is usually administered as a standard non-weight-based dose. We hypothesized that the efficacy of vasopressin may be influenced by body weight.. The primary objective was to determine if the effects of vasopressin on other vasopressor dosing requirements is related to body weight. Secondary objectives included evaluation of blood pressure and heart rate after the start of vasopressin infusion.. A retrospective, cohort study in a large academic health center was conducted. Sixty-four adult inpatients with septic shock (26 medical intensive care unit and 38 surgical intensive care unit) who required vasopressor administration including vasopressin therapy were included. Dosing requirements of vasopressors were captured 1 hour before and during the hour of vasopressin initiation and 2 and 4 hours later. Other information collected during the study period included blood pressure, mean arterial pressure, and heart rate.. Most of the patients (n = 61) received vasopressin at a dose of 0.04 U/min. Changes in vasopressor dosing were significantly correlated with weight-adjusted vasopressin at 2 hours (correlation coefficient = -0.36, P = .03) and 4 hours (correlation coefficient = -0.46, P < .001). Use of vasopressin was associated with significant increases in systolic blood pressure, diastolic blood pressure, and mean arterial pressure at each time point compared with baseline.. Effects of vasopressin on catecholamine dosing requirements in the setting of septic shock may be influenced by body weight. Prospective studies are needed to examine weight-based dosing of vasopressin in this setting.

Topics: Blood Pressure; Body Weight; Drug Dosage Calculations; Drug Therapy, Combination; Female; Heart Rate; Humans; Infusions, Intravenous; Male; Middle Aged; Norepinephrine; Retrospective Studies; Shock, Septic; Statistics, Nonparametric; Vasoconstrictor Agents; Vasopressins

It is important to understand the mechanism on the fluid shift and volume regulation occurring in astronauts after spaceflight for future life in space. In the present study, we examined the time-dependent alteration of anti-diuretic hormone (ADH) concentrating on the water reabsorption system in hindlimb unloaded rats. Male Sprague-Dawley rats were hindlimb unloaded for 1 (HU1), 7(HU7), 14 days (HU14) or rested in the ground for 3 days after HU14 (HU14+3). The plasma ADH and angiotensin II level showed peak value at HU7, and the alterations were restored at HU14. However, several serum electrolytes (Na, K, Cl) were not changed regardless of HU period. In the immunohistochemical study, we examined that ADH and c-Fos immunoreactivities (IR) were maximized at HU7 in the paraventricular nucleus (PVN) and supraoptic nucleus (SON). Aquaporin 2 (AQP2) IR also was increased in the renal collecting duct for water re-absorption at HU7 showing a similar pattern with ADH. These results present a series of physiological ADH system alteration following to period of hindlimb unloading stimulus, indicating that ADH system is activated significantly at HU7. In addition, our results suggest that ADH system activation may be involved in anti-diuretic phenomenon in early spaceflight period. Furthermore, it is speculated that ADH system may require 14 days for adaptation to microgravity.

Topics: Angiotensin II; Animals; Aquaporin 2; Blood Urea Nitrogen; Body Weight; Creatinine; Diuretics; Electrolytes; Hindlimb Suspension; Kidney Tubules; Male; Paraventricular Hypothalamic Nucleus; Proto-Oncogene Proteins c-fos; Rats; Rats, Sprague-Dawley; Supraoptic Nucleus; Vasopressins; Water

The Na-Cl cotransporter (NCC), which is the target of inhibition by thiazides, is located in close proximity to the chloride-absorbing transporter pendrin in the kidney distal nephron. Single deletion of pendrin or NCC does not cause salt wasting or excessive diuresis under basal conditions, raising the possibility that these transporters are predominantly active during salt depletion or in response to excess aldosterone. We hypothesized that pendrin and NCC compensate for loss of function of the other under basal conditions, thereby masking the role that each plays in salt absorption. To test our hypothesis, we generated pendrin/NCC double knockout (KO) mice by crossing pendrin KO mice with NCC KO mice. Pendrin/NCC double KO mice displayed severe salt wasting and sharp increase in urine output under basal conditions. As a result, animals developed profound volume depletion, renal failure, and metabolic alkalosis without hypokalemia, which were all corrected with salt replacement. We propose that the combined inhibition of pendrin and NCC can provide a strong diuretic regimen without causing hypokalemia for patients with fluid overload, including patients with congestive heart failure, nephrotic syndrome, diuretic resistance, or generalized edema.

Topics: Alkalosis; Animals; Anion Transport Proteins; Body Weight; Diuresis; Kidney; Kidney Function Tests; Mice; Mice, Knockout; Models, Biological; Potassium; Receptors, Drug; Renal Insufficiency; Sodium; Sodium Chloride; Sodium Chloride, Dietary; Solute Carrier Family 12, Member 3; Sulfate Transporters; Symporters; Vasopressins; Water-Electrolyte Balance

Vasopressin (VP) plays an important role in hypothalamo-pituitary-adrenal (HPA) axis regulation and in stress-related disorders. Our previous studies confirmed the role of VP in acute situations, where VP-deficient Brattleboro rats had less depression-like behaviour compared to animals that express VP. In this study, we test the hypothesis that VP-deficient rats are more resistant to the development of chronic HPA axis hyperactivity and depression-like symptoms after chronic unpredictable stress (CUS). Male VP-deficient Brattleboro rats were compared to their heterozygous littermates (controls). CUS consisted of different mild stimuli for 5 weeks. Elevated plus maze and forced swim test were used for behavioural characterization, while organs and blood for HPA axis parameters were collected at the end of the experiment. In controls, CUS resulted in the development of chronic stress state characterized by typical somatic (body weight reduction, thymus involution) and endocrine changes (resting plasma ACTH and corticosterone elevation and POMC mRNA elevation in anterior lobe of the pituitary). Floating time in the forced swim test was enhanced together with reduced open arm entries on elevated plus maze and a reduction in daily food intake. Unexpectedly, the lack of VP did not alter the effect of CUS on the somatic and behavioural measures, but only prevented CUS-induced corticosterone changes. In conclusion, lifelong VP-deficiency has a positive effect on corticosterone elevation following CUS but does not affect the behavioural consequences of CUS. It is likely that the interplay of several related factors, rather than an alteration in a single neuropeptide, modulates behaviour and disease pathogenesis.

Topics: Adrenocorticotropic Hormone; Animals; Anxiety; Behavior, Animal; Body Weight; Corticosterone; Depression; Drinking; Eating; Hypothalamo-Hypophyseal System; Male; Neuropsychological Tests; Organ Size; Pituitary-Adrenal System; Rats; Rats, Brattleboro; Stress, Psychological; Vasopressins

Nasal obstruction is a risk factor in sleep-disordered breathing with a negative impact on the quality of life in humans. We investigated hydration changes produced by short term reversible, bilateral, nasal obstruction in young developing rat pups. Physiological parameters of growth (weight gain and gastric content weight) and dehydration were analyzed during two periods; during nasal obstruction at post-natal day 8 (days 9, 11 and 13), plus 7 and 90 days after recovery of nasal breathing (day 15 and adulthood). Body weight gain in oral breathing rat pups was slower compared to controls. Gastric weight was decreased significantly only in oral breathing rat pups on days 9 and 11 while plasma osmolality and vasopressin levels increased (indicators of dehydration). There were no differences between controls and treated rat pups by day 15, or at adulthood. Short term nasal obstruction-induced forced oral breathing, decreased gastric content which had a negative impact on growth and blood glucose concentration in the short term for female rat pups. Plasma corticosterone levels increased during the dehydration but were normal in males by 90 days. This could be a model for blocked nose syndrome in the newborn. Possible long term consequences on development are discussed.

Topics: Adrenal Cortex Hormones; Analysis of Variance; Animals; Animals, Newborn; Behavior, Animal; Blood Glucose; Body Weight; Dehydration; Female; Male; Mouth Breathing; Organ Size; Osmolar Concentration; Radioimmunoassay; Rats; Rats, Wistar; Sleep Apnea Syndromes; Stress, Psychological; Time Factors; Vasopressins; Weight Gain

Sweat Na(+) concentration ([Na(+)]) varies greatly among individuals and is particularly high in cystic fibrosis (CF). The purpose of this study was to determine whether excess sweat [Na(+)] differentially impacts thirst drive and other physiological responses during progressive dehydration via exercise in the heat. Healthy subjects with high-sweat [Na(+)] (SS) (91.0 ± 17.3 mmol/l), Controls with average sweat [Na(+)] (43.7 ± 9.9 mmol/l), and physically active CF patients with very high sweat [Na(+)] (132.6 ± 6.4 mmol/l) cycled in the heat without drinking until 3% dehydration. Serum osmolality increased less (P < 0.05) in CF (6.1 ± 4.3 mosmol/kgH(2)O) and SS (8.4 ± 3.0 mosmol/kgH(2)O) compared with Control (14.8 ± 3.5 mosmol/kgH(2)O). Relative change in plasma volume was greater (P < 0.05) in CF (-19.3 ± 4.5%) and SS (-18.8 ± 3.1%) compared with Control (-14.3 ± 2.3%). Thirst during exercise and changes in plasma levels of vasopressin, angiotensin II, and aldosterone relative to percent dehydration were not different among groups. However, ad libitum fluid replacement was 40% less, and serum NaCl concentration was lower for CF compared with SS and Control during recovery. Despite large variability in sweat electrolyte loss, thirst appears to be appropriately maintained during exercise in the heat as a linear function of dehydration, with relative contributions from hyperosmotic and hypovolemic stimuli dependent upon the magnitude of salt lost in sweat. CF exhibit lower ad libitum fluid restoration following dehydration, which may reflect physiological cues directed at preservation of salt balance over volume restoration.

Topics: Adult; Aldosterone; Angiotensin II; Body Weight; Case-Control Studies; Cystic Fibrosis; Dehydration; Exercise; Female; Hot Temperature; Humans; Male; Osmolar Concentration; Plasma Volume; Sodium; Sweat; Thirst; Vasopressins

This study was performed to investigate the effects of L-thyroxine treatment on plasma vasopressin (AVP) levels in rats with hypothyroidism induced by propylthiouracil (PTU). Animals were separated into three groups each having 6 rats: control, PTU, PTU+L-thyroxine groups. Then, the groups were further divided into 3 sub-groups including 6 rats (a; basal, b; hypertonic stimulated and c; hypovolemic stimulated). At the end of the experiments all rats were decapitated in order to obtain plasma samples for analysis in terms of Hct, osmolality, TT 3 , TT 4 and vasopressin. Haematocrit (Hct) levels were the highest in hypovolemic stimulated sub-group (P < 0.001). Osmolality levels were higher in hypertonic stimulated sub-groups (P < 0.001). Total T 3 and T 4 values were the lowest in the PTU group and the highest in the L-thyroxine treated group (P < 0.001). Plasma AVP levels were reduced by hypothyroidism. However, L-thyroxine treatment after the hypothyroidism prevented this reduction (P < 0.001). Vasopressin responses to basal, hypovolemic and hypertonic stimulations were the lowest in the PTU group (P < 0.001). The results of the present study show that basal and stimulated plasma vasopressin levels are reduced in PTU-induced hypothyroidism. However, L-thyroxine treatment following hypothyroidism prevents this reduction.

Topics: Animals; Antithyroid Agents; Body Weight; Dietary Supplements; Hypertonic Solutions; Hypothyroidism; Hypovolemia; Male; Propylthiouracil; Rats; Rats, Wistar; Thyroxine; Vasopressins

Nitric oxide (NO) is a short-lived radical that functions as a neurotransmitter in the central nervous system and plays a physiological role in the regulation of hypothalamic-pituitary-adrenal axis and vasopressinergic axis. In the present study, we aimed to investigate the interaction between the generation of NO and vasopressin (AVP) and corticosterone release after 3 days of water deprivation in rats. Animals were previously treated with intraperitoneal (i.p.) saline or L-nitro-arginine methyl ester (L-NAME) injection. L-NAME is a nonspecific inhibitor of nitric oxide synthases. In control rats given i.p. saline or L-NAME, hypothalamic, pituitary, and plasma AVP levels and plasma corticosterone did not change from baseline levels (p>0.05). Three days of water deprivation increased significantly the corticosterone levels in plasma (p<0.01) and AVP levels in hypothalamus and plasma (p<0.01), but not in pituitary, which showed a significant decrease. These variations were concomitant with the elevation of nitrates/nitrates in plasma. L-NAME injection abolished significantly (p<0.01) the elevation of plasma corticosterone and hypothalamic AVP levels induced by water deprivation. These findings showed that in water-deprived rats, nitric oxide synthase inhibition by L-NAME inhibits corticosterone and vasopressin release, suggesting a potent stimulatory role of NO.

Topics: Adrenal Cortex Hormones; Animals; Body Weight; Brain; Hematocrit; Hypothalamus; Male; Neurotransmitter Agents; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase; Prostaglandins; Rats; Rats, Wistar; Vasopressins; Water

Klotho is a membrane protein participating in the inhibitory effect of FGF23 on the formation of 1,25-dihydroxyvitamin-D(3) [1,25(OH)(2)D(3)]. It participates in the regulation of renal tubular phosphate reabsorption and stimulates renal tubular Ca(2+) reabsorption. Klotho hypomorphic mice (klotho(hm)) suffer from severe growth deficit, rapid aging, and early death, events largely reversed by a vitamin D-deficient diet. The present study explored the role of Klotho deficiency in mineral and electrolyte metabolism. To this end, klotho(hm) mice and wild-type mice (klotho(+/+)) were subjected to a normal (D(+)) or vitamin D-deficient (D(-)) diet or to a vitamin D-deficient diet for 4 wk and then to a normal diet (D(-/+)). At the age of 8 wk, body weight was significantly lower in klotho(hm)D(+) mice than in klotho(+/+)D(+) mice, klotho(hm)D(-) mice, and klotho(hm)D(-/+) mice. Plasma concentrations of 1,25(OH)(2)D(3,) adrenocorticotropic hormone (ACTH), antidiuretic hormone (ADH), and aldosterone were significantly higher in klotho(hm)D(+) mice than in klotho(+/+)D(+) mice. Plasma volume was significantly smaller in klotho(hm)D(-/+) mice, and plasma urea, Ca(2+), phosphate and Na(+), but not K(+) concentrations were significantly higher in klotho(hm)D(+) mice than in klotho(+/+)D(+) mice. The differences were partially abrogated by a vitamin D-deficient diet. Moreover, the hyperaldosteronism was partially reversed by Ca(2+)-deficient diet. Ussing chamber experiments revealed a marked increase in amiloride-sensitive current across the colonic epithelium, pointing to enhanced epithelial sodium channel (ENaC) activity. A salt-deficient diet tended to decrease and a salt-rich diet significantly increased the life span of klotho(hm)D(+) mice. In conclusion, the present observation disclose that the excessive formation of 1,25(OH)(2)D(3) in Klotho-deficient mice results in extracellular volume depletion, which significantly contributes to the shortening of life span.

Topics: Adrenocorticotropic Hormone; Aldosterone; Animals; Blood Chemical Analysis; Blood Pressure; Body Weight; Calcitriol; Diffusion Chambers, Culture; Electrolytes; Fibroblast Growth Factor-23; Glucuronidase; Hyperaldosteronism; Klotho Proteins; Mice; Mice, Knockout; Parathyroid Hormone; Plasma Volume; Survival; Vasopressins

Anomalies in hormonal and neurotransmitter status during perinatal period can lead to lifespan alterations in the central nervous system. Vasopressin is present early in the brain and has various mitogenic, metabolic and physiological actions, e.g. in water homeostasis or in the regulation of the hypothalamo-pituitary-adrenal (HPA) axis. Therefore we examine the possible role of vasopressin in perinatal development with special attention to the influence of maternal genotype and to the HPA axis regulation. We compared homozygous vasopressin deficient (di/di) Brattleboro rats to their heterozygous (di/+) littermates both from di/+ and di/di mother. Higher locomotion due to reduced adaptation was present at preweaning. During the first 10 days of life the di/di pups from di/di mother were the smallest, while in the later perinatal period the genotype of the pups became the more important determinant of the somatic development, namely the di/di pups from both mothers had reduced weight gain. Generally the lack of vasopressin in the pups fastened the somatic development (pinna detachment, eye and ear opening, incisor eruption) however the neurobehavioral development (palmar grasp reflex, righting reflex, negative geotaxis, etc.) was not influenced profoundly by either the mother's or the pup's genotype. The lack of vasopressin in pups abolished the 24 h maternal separation induced adrenocorticotrop hormone (ACTH) elevation while the accompanying corticosterone rises were even higher. The vasopressin deficiency of the mother reduced the resting ACTH and all corticosterone levels in all pups. So we can conclude that the lack of vasopressin speeds up the development, probably there is a greater drive for self-sufficiency in these animals. The mother's vasopressin deficiency reduced the HPA axis reactivity of the pups. The role of vasopressin in the HPA axis regulation is important during the perinatal period independently from the mother's genotype. The large discrepancy between ACTH and corticosterone regulation requires further studies.

Topics: Adrenocorticotropic Hormone; Animals; Animals, Newborn; Behavior, Animal; Body Weight; Corticosterone; Genotype; Hypothalamo-Hypophyseal System; Maternal Deprivation; Mothers; Motor Activity; Pituitary-Adrenal System; Rats; Rats, Brattleboro; Rats, Transgenic; Vasopressins

The hypothesis that vasopressin (VP) becomes the main mediator of pituitary corticotroph responsiveness during chronic hypothalamic pituitary adrenal (HPA) axis activation was tested by examining the effect of pharmacologic VP receptor blockade on the adrenocorticotropic hormone (ACTH) and corticosterone responses of 14-day repeatedly restrained rats. In spite of the increased vasopressinergic activity, repeatedly restrained rats showed lower ACTH and corticosterone responses to 10 min white noise compared with handled controls. These responses were unchanged by injection of the nonpeptide-selective V1b receptor antagonist SSR149415 i.v., 1 h before noise application. In contrast to noise stress, plasma ACTH responses to i.p. hypertonic saline injection were enhanced in the repeatedly restrained rats compared with handled controls, but responses were also unaffected by SSR149415 administered orally, daily 1 h before restraint. Since SSR149415 effectiveness was low, we used minipump infusion of the peptide V1 receptor antagonist, dGly[Phaa1,D-tyr(et), Lys, Arg]VP (V1-Ant) for 14 days, which effectively blocked ACTH responses to exogenous VP. Chronic V1-Ant infusion reduced plasma ACTH responses to i.p. hypertonic saline in handled controls but not in repeatedly restrained rats. These data suggest that the increased vasopressinergic activity characteristic of chronic stress plays roles other than mediating the hypersensitivity of the HPA axis to a novel stress.

Topics: Adrenocorticotropic Hormone; Animals; Antidiuretic Hormone Receptor Antagonists; Body Weight; Corticosterone; Drinking; Eating; Humans; Hypothalamo-Hypophyseal System; Indoles; Male; Noise; Pituitary-Adrenal System; Pyrrolidines; Rats; Rats, Sprague-Dawley; Receptors, Vasopressin; Restraint, Physical; Stress, Psychological; Vasopressins

The polycystic kidney diseases (PKD) are a group of genetic disorders causing renal failure and death from infancy to adulthood. Arginine vasopressin (AVP) V2 receptor antagonists inhibit cystogenesis in animal models of cystic kidney diseases, presumably by downregulating cAMP signaling, cell proliferation, and chloride-driven fluid secretion. For confirmation that the protective effect of these drugs is due to antagonism of AVP, PCK (Pkhd1(-/-)) and Brattleboro (AVP(-/-)) rats were crossed to generate rats with PKD and varying amounts of AVP. At 10 and 20 weeks of age, PCK AVP(-/-) rats had lower renal cAMP and almost complete inhibition of cystogenesis compared with PCK AVP(+/+) and PCK AVP(+/-) rats. The V2 receptor agonist 1-deamino-8-d-arginine vasopressin increased renal cAMP and recovered the full cystic phenotype of PCK AVP(-/-) rats and aggravated the cystic disease of PCK AVP(+/+) rats but did not induce cystic changes in wild-type rats. These observations indicate that AVP is a powerful modulator of cystogenesis and provide further support for clinical trials of V2 receptor antagonists in PKD.

Topics: Animals; Arginine Vasopressin; Body Weight; Cell Division; Crosses, Genetic; Cyclic AMP; Cysts; Female; Kidney; Male; Organ Size; Polycystic Kidney Diseases; Rats; Rats, Brattleboro; Vasopressins

The arteriovenous fistula model of circulation can produce a high output and low peripheral resistance situation. Here, we have examined the effects of noradrenaline, vasopressin and sodium nitroprusside on cardiac index, mean arterial blood pressure, venous tone, resistance to venous return, arterial resistance, and blood volume in chronically shunted anaesthetized rats. The cardiac index of rats with chronic arteriovenous fistula (AVF) was significantly higher (36.65+/-2.28 ml/min per 100 g; (mean+/-S.E.M.; n=24) in comparison to sham-operated rats (20.04+/-0.86 ml/min per 100 g; mean+/-S.E.M.; n=8). Cardiac index did not significantly change during the infusion of noradrenaline (1.0, 3.0 and 10 microg/kg per min), vasopressin (10, 30, 100 ng/kg per min) or sodium nitroprusside (0.1, 0.3 and 1.0 microg/kg per min) compared to saline infusion in AVF animals. Infusion of noradrenaline significantly increased heart rate, dP/dt, mean circulatory filling pressure (Pmcf) and resistance to venous return without affecting mean arterial blood pressure when compared to saline infusion. Administration of vasopressin significantly increased dP/dt, mean arterial blood pressure, and Pmcf without affecting heart rate, resistance to venous return or arterial resistance compared to saline infusion. Infusion of sodium nitroprusside did not significantly affect any haemodynamic parameter measured when compared to saline infusion. The results indicate that the presence of chronic AVF alters responsiveness of the various segments of the circulatory system to vasoactive agents. Moreover, it produces a major impediment to overall changes that can normally be induced following the infusion of such agents.

Topics: Anesthesia; Animals; Arteriovenous Fistula; Blood Pressure; Blood Volume; Body Weight; Cardiac Output; Cardiac Output, High; Heart; Heart Rate; Lung; Male; Nitroprusside; Norepinephrine; Organ Size; Rats; Rats, Sprague-Dawley; Vascular Resistance; Vasoconstrictor Agents; Vasodilator Agents; Vasopressins

Previous studies have demonstrated that type 1 diabetes is characterized by hypercorticism and lack of periodicity in adrenal hormone secretion. In the present study, we tested the hypothesis that hypercorticism is initiated by an enhanced release of ACTH leading subsequently to adrenocortical growth and increased output of adrenocortical hormones. To test this hypothesis, we used the streptozotocin (STZ)-induced diabetes mouse model and measured hypothalamic-pituitary-adrenal axis activity at different time points. The results showed that the expected rise in blood glucose levels induced by STZ treatment preceded the surge in corticosterone secretion, which took place 1 d after diabetes onset. Surprisingly, circulating ACTH levels were not increased and even below control levels until 1 d after diabetes onset and remained low until d 11 during hypercorticism. In response to ACTH (but not vasopressin), cultures of adrenal gland cells from 11-d diabetic mice secreted higher amounts of corticosterone than control cells. Real-time quantitative PCR revealed increased expression of melanocortin 2 and melanocortin 5 receptors in the adrenal glands at 2 and 11 d of STZ-induced diabetes. AVP mRNA expression in the paraventricular nucleus of the hypothalamus was increased, whereas hippocampal MR mRNA was decreased in 11-d diabetic animals. GR and CRH mRNAs remained unchanged in hippocampus and paraventricular nucleus of diabetic mice at all time points studied. These results suggest that sensitization of the adrenal glands to ACTH rather than an increase in circulating ACTH level is the primary event leading to hypercorticism in the STZ-induced diabetes mouse model.

Topics: Adrenal Glands; Adrenocortical Hyperfunction; Adrenocorticotropic Hormone; Animals; Blood Glucose; Body Weight; Cells, Cultured; Chronic Disease; Corticosterone; Corticotropin-Releasing Hormone; Diabetes Mellitus, Experimental; Hypothalamo-Hypophyseal System; In Situ Hybridization; Male; Mice; Organ Size; Pituitary-Adrenal System; Radioimmunoassay; Receptor, Melanocortin, Type 2; Receptors, Corticotropin; Receptors, Melanocortin; Receptors, Mineralocorticoid; Reverse Transcriptase Polymerase Chain Reaction; Time Factors; Vasopressins

Limbic and cortical neurocircuits profoundly influence hypothalamic-pituitary-adrenal (HPA) axis responses to stress yet have little or no direct projections to the hypothalamic paraventricular nucleus (PVN). Numerous lines of evidence suggest that the bed nucleus of the stria terminalis (BST) is well positioned to relay limbic information to the PVN. The BST comprises multiple anatomically distinct nuclei, of which some are known to receive direct limbic and/or cortical input and to heavily innervate the PVN. Our studies test the hypothesis that subregions of the BST differentially regulate HPA axis responses to acute stress. Male Sprague Dawley rats received bilateral ibotenate lesions, targeting either the principal nucleus in the posterior BST or the dorsomedial/fusiform nuclei in the anteroventral BST. Posterior BST lesions elevated plasma ACTH and corticosterone in response to acute restraint stress, increased stress-induced PVN c-fos mRNA, and elevated PVN corticotropin-releasing hormone (CRH) and parvocellular arginine vasopressin (AVP) mRNA expression relative to sham-lesion animals. In contrast, anterior BST lesions attenuated the plasma corticosterone response and decreased c-fos mRNA induction in the PVN but did not affect CRH and parvocellular AVP mRNA expression in the PVN. These data suggest that posterior BST nuclei are involved in inhibition of the HPA axis, whereas the anteroventral BST nuclei are involved in HPA axis excitation. The results indicate that the BST contains functional subdomains that play different roles in integrating and processing limbic information in response to stress and further suggest that excitatory as well as inhibitory limbic information is funneled through these important cell groups.

Topics: Acute Disease; Adrenal Glands; Adrenocorticotropic Hormone; Animals; Body Weight; Corticosterone; Corticotropin-Releasing Hormone; Glutamate Decarboxylase; Hypothalamo-Hypophyseal System; Isoenzymes; Limbic System; Male; Organ Size; Paraventricular Hypothalamic Nucleus; Pituitary-Adrenal System; Proto-Oncogene Proteins c-fos; Rats; Rats, Sprague-Dawley; Restraint, Physical; RNA, Messenger; Septal Nuclei; Stress, Physiological; Thymus Gland; Vasopressins

To test the effect of dehydration on brain atrial natriuretic peptide (ANP) concentrations in areas important to salt appetite, water balance and cardiovascular regulation, we subjected rats to dehydration and rehydration and measured ANP concentration in 18 brain areas, as well as all relevant peripheral parameters. Water deprivation decreased body weight, blood pressure, urine volume, and plasma ANP, while it increased urine and plasma osmolality, angiotensin II, and vasopressin. ANP greatly increased in 17 and 18 brain areas (all cut cerebral cortex) by 24 h. Rehydration for 12 h corrected all changes evoked by dehydration, including elevated ANP levels in brain. We conclude that chronic dehydration results in increased ANP in brain areas important to salt appetite and water balance. These results support a role for ANP as a neuroregulatory substance that participates in salt and water balance.

Topics: Angiotensin II; Animals; Atrial Natriuretic Factor; Blood Pressure; Body Weight; Brain; Cerebral Cortex; Dehydration; Male; Osmolar Concentration; Rats; Rats, Wistar; Thirst; Time Factors; Urine; Vasopressins; Water-Electrolyte Balance

Vasopressin plays an important role in the hypothalamo-pituitary-adrenal axis regulation as well as in stress-related disorders. A common view suggested that the role of vasopressin is especially important during chronic stresses. Here we tested the hypothesis that vasopressin-deficient rats may be more resistant to the development of chronic hypothalamo-pituitary-adrenal axis hyperactivity after chronic mild stress.. Male vasopressin deficient Brattleboro rats were compared to their heterozygous litter mates. Chronic mild stress consisted of different mild stimuli (e.g. wet cages, restraint) for 6 week. The corticosterone changes were followed by repeated tail cutting and organs and blood were collected from decapitated rats.. In controls, chronic mild stress resulted in symptoms of chronic stress state characterized by typical somatic (body weight reduction, thymus involution) and endocrine changes (resting plasma ACTH and corticosterone elevation and POMC mRNA elevation in anterior lobe of the pituitary). Unexpectedly, the lack of vasopressin could not influence any chronic mild stress-induced changes.. Somatic changes and endocrine effects of chronic mild stress are similar in control and vasopressin deficient animals. This suggests that either vasopressin is not indispensable for activating the hypothalamo-pituitary-adrenal axis by chronic stress or the absence of vasopressin is compensated by other mediators (e.g. CRH) in Brattleboro rats.

Topics: Adrenal Glands; Adrenocorticotropic Hormone; Animals; Body Weight; Chronic Disease; Corticosterone; Depression; Disease Models, Animal; Heterozygote; Hypothalamo-Hypophyseal System; Male; Organ Size; Pituitary Gland, Anterior; Pituitary-Adrenal System; Pro-Opiomelanocortin; Rats; Rats, Brattleboro; Stress, Psychological; Thymus Gland; Vasopressins

1. High-sodium intake may increase blood pressure and diabetes is a salt-sensitive condition. In the present study, we evaluated cardiovascular changes and their neurohumoral mechanisms in streptozotocin (STZ)-diabetic rats that underwent chronic salt loading. 2. We studied male Wistar rats (150-280 g) 14 days after the injection of either STZ (50 mg/kg, i.v.; D; n = 18) or citrate buffer (C; n = 16). After the induction of diabetes, animals were maintained for 14 days with free access to standard rat chow and tap water (C and D groups) or 1% NaCl solution (C-S and D-S groups). We conducted two experiments. Experiment 1 consisted of basal arterial pressure (AP) measurement (30 min) followed by the evaluation of AP responsiveness to phenylephrine and sodium nitroprusside. One day later, with the rats anaesthetized, a blood sample was collected to test for glycaemia, plasma angiotensin-converting enzyme (ACE) activity and renin. Kidneys were removed for the determination of tissue ACE activity. Experiment 2 comprised 24 h urine collection followed by 3 days of cardiovascular records, which consisted of a 30 min basal AP measurement, followed by injection of blockers of the vasopressin system, the renin-angiotensin system (RAS) and the sympathetic system. Basal haemodynamic data, baroreflex evaluation and AP responses to blockade of the vasopressin system with vasopressin V(1) receptor antagonist (aAVP; 10 mg/kg, i.v.), the RAS by losartan (10 mg/kg, i.v.) and the sympathetic system by hexamethonium (20 mg/kg, i.v.) were determined. 3. Glycaemia was similar between C and C-S (P = 0.612) and between D and D-S (P = 0.552), but higher in diabetic compared with non-diabetic rats (P < 0.0001). The D-S rats had an increment of 24% in mean AP compared with D (120 +/- 4 vs 97 +/- 2 mmHg, respectively; P = 0.0001), which was not seen in C-S compared with C rats. A positive association was noted between urinary sodium and mean AP (r = 0.37; P = 0.04). Plasma renin was undetectable in D-S rats. The response to acute drug blockade of vasopressin and the RAS was similar among groups, but hexamethonium elicited a more pronounced decrease in AP in D-S compared with D rats (P = 0.001). 4. The main neurohumoral mechanisms of salt-induced cardiovascular changes in STZ-diabetes are increased sodium and vascular sensitivity to adrenergic stimuli, which act in combination to produce a final result of higher AP levels, a finding not observed in control rats. Baroreflex derangemen

Topics: Angiotensin II Type 1 Receptor Blockers; Animals; Arginine Vasopressin; Baroreflex; Blood Glucose; Blood Pressure; Body Weight; Diabetes Mellitus, Experimental; Ganglionic Blockers; Heart Rate; Hematocrit; Hexamethonium; Hormone Antagonists; Hypertension; Kidney; Losartan; Male; Nitroprusside; Organ Size; Peptidyl-Dipeptidase A; Phenylephrine; Rats; Rats, Wistar; Renin; Renin-Angiotensin System; Sodium Chloride, Dietary; Sympathetic Nervous System; Vasoconstrictor Agents; Vasodilator Agents; Vasopressins

We studied the mechanisms of genetic-early environmental interactions to modulate adult stress-coping and tested the hypothesis that prenatal stress (PS) can differentially alter the consequences of a genetic predisposition to either hyper- or hypo-anxiety. Exposure of male Wistar rats, bred for high (HAB) or low (LAB) anxiety-related behaviour, to PS between pregnancy days 4 and 18 resulted in opposite effects on anxiety in adulthood, i.e. HAB rats became less and LAB rats became more anxious compared with their unstressed controls (plus-maze and holeboard). The high anxiety of HAB controls was accompanied by elevated expression of vasopressin and corticotropin-releasing hormone (CRH) mRNA within the hypothalamic paraventricular nucleus compared with LAB rats. PS reduced CRH mRNA expression in HAB rats but increased vasopressin mRNA expression in LAB rats, which may explain the opposite effects of PS on adult emotionality. Differential effects of PS were also found with respect to hypothalamo-pituitary-adrenal axis reactivity; the hypothalamo-pituitary-adrenal hyper-response in virgin female HAB controls became attenuated after PS, without affecting plasma corticosterone concentrations in LAB rats. Differences in maternal plasma corticosterone measured between pregnancy days 6 and 14 of HAB and LAB dams or differential effects of PS on maternal behaviour can be excluded. In conclusion, exposure of rats with genetically determined high or low emotionality to PS mitigates the extremes in behavioural and neuroendocrine stress-coping, thus allowing adequate and similar behavioural responses to potentially dangerous stimuli in adulthood. Differential effects of PS on the activity of the brain vasopressin and CRH systems might represent possible underlying molecular mechanisms.

Topics: Analysis of Variance; Animals; Animals, Newborn; Anxiety; Behavior, Animal; Body Weight; Corticotropin-Releasing Hormone; Exploratory Behavior; Female; Gene Expression; Hypothalamus; In Situ Hybridization; Male; Maze Learning; Pregnancy; Prenatal Exposure Delayed Effects; Radioimmunoassay; Rats; Rats, Wistar; RNA, Messenger; Stress, Physiological; Time Factors; Vasopressins; Vocalization, Animal

Aldosterone plays a crucial role in controlling mineral balance in our body. The mechanism of aldosterone has been reported to elevate renal Na+ reabsorption by stimulating expression of epithelial Na+ channel (ENaC) and also activate an ENaC-regulating protein kinase, serum and glucocorticoid-regulated kinase 1 (SGK1). However, it is unknown whether aldosterone shows its stimulatory action on ENaC and SGK1 under an abnormal, salt-sensitive hypertensive condition. To clarify this point, we studied how aldosterone regulates expression of ENaC and SGK1 in Dahl salt-sensitive (DS) rat that shows hypertension with high salt diet. RNA and protein were extracted from the kidney 6 h after application of aldosterone (1.5 mg/kg body weight) subcutaneously injected into adrenalectomized DS and Dahl salt-resistant (DR) rats. Aldosterone decreased mRNA expression of beta- and gamma-ENaC in DS rat unlike DR rat, while aldosterone increased alpha-ENaC mRNA expression in DS rat similar to DR rat. Further, we found that aldosterone elevated SGK1 expression in DR rat, but not in DS rat. These observations indicate that ENaC and SGK1 are abnormally regulated by aldosterone in salt-sensitive hypertensive rats, suggesting that disturbance of the aldosterone regulation would be one of factors causing salt-sensitive hypertension.

Topics: Aldosterone; Animals; Blotting, Western; Body Weight; Epithelial Sodium Channels; Extracellular Signal-Regulated MAP Kinases; Gene Expression Regulation; Hypertension; Immediate-Early Proteins; Kidney; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Models, Statistical; Phosphorylation; Protein Serine-Threonine Kinases; Rats; Rats, Inbred Dahl; Reverse Transcriptase Polymerase Chain Reaction; RNA; RNA, Messenger; Salts; Sodium; Sodium Channels; Time Factors; Vasopressins

The present study was performed to determine how l-thyroxine-induced hyperthyroidism affects the vasopressin response to different stimulations (isotonic, hypertonic and hypovolemic) in rats. Spraque-Dawley rats were initially separated into 3 groups; control (n=24), sham hyperthyroidism (n=24, hyperthyroidism (n=24). At the end of the experiment additional sub-groups were formed before decapitation. These sub-groups were formed as; without stimulation (n=6), isotonic stimulation (n=6), hypertonic stimulation (n=6) and hypovolemic stimulation (n=6). Total T3, total T4 and AVP levels were evaluated in the plasma. Haematocrit and osmolality levels were also determined. When the parameters related to thyroid hormones were evaluated, it was determined that total T3 and T4 levels were higher in hyperthyroid group than the other groups. Plasma AVP levels showed more increase in hyperthyroid group both in basal grade and against to hypertonic and hypovolemic stimulations than the other groups (P<0.001). The results of the present study indicate that l-thyroxine-induced experimental hyperthyroidism increased basal and stimulated AVP release in rats.

Topics: Animals; Body Weight; Hematocrit; Hyperthyroidism; Hypertonic Solutions; Hypovolemia; Isotonic Solutions; Male; Osmolar Concentration; Rats; Rats, Sprague-Dawley; Thyroxine; Triiodothyronine; Vasopressins; Water-Electrolyte Balance

Nitric oxide has been suggested to be involved in the regulation of fluid and nutrient homeostasis. In the present investigation, vasopressin and nitric oxide metabolite (nitrite and nitrate) levels were determined in plasma of male Wistar rats submitted to water or food deprivation for three days. Hematocrit and plasma sodium showed marked increase in dehydrated and starved rats. Potassium levels and plasma volume decreased in both treated groups. Plasma osmolality and vasopressin levels were significantly elevated in water deprived (362.8 +/- 7.1 mOsm/kg H2O, 17.3 +/- 2.7 pg/ml, respectively, p < 0.001) rats, but not in food deprived (339.9 +/- 5.0, 1.34 +/- 0.28) rats, compared to the controls (326.1 +/- 4.1, 1.47 +/- 0.32). The alterations observed in plasma vasopressin levels were related to plasma osmolality rather than plasma volume. Plasma levels of nitrite and nitrate were markedly increased in both water and food deprived rats (respectively, 2.19 +/- 0.29 mg/l and 2.22 +/- 0.17 mg/l versus 1.33 +/- 0.19 mg/l, both p < 0.01). There was a significant negative correlation between plasma nitrite and nitrate concentration and plasma volume. These results suggest that both dehydration and starvation increase plasma nitric oxide, probably by activation of nitric oxide synthases. The release of nitric oxide may participate in the regulation of the alteration in blood flow, fluid and nutrient metabolism caused by water deprivation or starvation.

Topics: Animals; Body Weight; Enzyme Activation; Food Deprivation; Hematocrit; Homeostasis; Male; Nitrates; Nitric Oxide; Nitric Oxide Synthase; Nitrites; Osmolar Concentration; Plasma Volume; Rats; Rats, Wistar; Regional Blood Flow; Sodium; Time Factors; Vasopressins; Water Deprivation

Regulation of vasopressin (VP) and oxytocin (OT) secretion involves integration of neural signals from hypothalamic osmoreceptors, ascending catecholaminergic and peptidergic cell groups in the brain stem, and local and autoregulatory afferents. Neuropeptide Y (NPY) is one factor that stimulates the release of VP and OT from the supraoptic (SON) and paraventricular nuclei of the hypothalamus via activation of Y1 receptors (Y1R). The current studies were designed to assess the regulation and distribution of NPY Y1R expression in the SON of male rats that were either given 2% NaCl drinking water (24-72 h) or water deprived (48 h). Subjecting male rats to these conditions resulted in significant increases in both the number of cells expressing Y1R immunoreactivity (ir) and the amount of Y1R protein per cell within the SON. Y1R immunoreactivity was increased in the magnocellular but not medial parvocellular paraventricular nuclei, and Y1R mRNA levels were increased in the SON of salt-loaded rats. Subpopulations of both VP and OT cells in the hypothalamus express Y1R immunoreactivity and a greater percentage of VP-ir cells express Y1R after salt loading. To control for potential effects of dehydration-induced anorexia, a group of euhydrate animals was pair fed with animals consuming 2% NaCl. No detectable change in Y1R expression was observed in the SON of pair-fed animals, even though body weights were significantly lower than controls. These data demonstrate that NPY Y1R gene and protein expression are increased in the SON of salt-loaded and water-deprived animals and provide a mechanism whereby NPY can support VP/OT release during prolonged challenges to fluid homeostasis.

Topics: Animals; Blood; Body Weight; Dehydration; Gene Expression; Hypothalamus; Immunohistochemistry; Male; Neurons; Osmolar Concentration; Oxytocin; Paraventricular Hypothalamic Nucleus; Rats; Rats, Sprague-Dawley; Receptors, G-Protein-Coupled; Receptors, Neuropeptide; Sodium Chloride; Supraoptic Nucleus; Vasopressins; Water Deprivation

In this study, the effects of reduced melatonin concentrations in the long-term period of pinealectomy on mean arterial blood pressure (BP) and vascular responses in isolated rat thoracic aorta were investigated. Rats were pinealectomized (Px) two months before the beginning of the studies. Rings of endothelium-intact and -denuded rat arteries were mounted in isolated tissue baths for the measurements of isometric contractile force. No significant difference was determined between the arterial BP of Px (88.1 +/- 1.9 mmHg) and control (83.8 +/- 1.2 mmHg) rats. All arteries isolated from control and Px rats showed essentially identical contractions in response to phenylephrine, serotonin, calcium, clonidine, vasopressin, and angiotensin-II. Only endothelin-1 (ET-1)-induced contractions in the endothelium-denuded vessels isolated from Px rats were found to be increased to some extent. Pinealectomy did not affect acetylcholine or sodium nitroprusside-induced relaxation in the rat aorta either. These data suggest that reduced melatonin levels two months after pinealectomy did not modify either the vascular reactivity to various vasoconstrictor agents except the partially increased contractile responses to ET-1 in the endothelium-denuded thoracic aortas of Px rats or the endothelium-dependent and -independent relaxations in rat thoracic aorta. Restoration of the increased vascular responses to some vasoconstrictor agents, which were reported previously, may be the reason of why the hypertension is temporary following pinealectomy.

Topics: Acetylcholine; Angiotensin II; Animals; Aorta, Thoracic; Body Weight; Clonidine; Dose-Response Relationship, Drug; Drug Synergism; Endothelin-1; Endothelium, Vascular; Heart; In Vitro Techniques; Male; Organ Size; Phenylephrine; Pineal Gland; Rats; Rats, Wistar; Serotonin; Time Factors; Vasoconstrictor Agents; Vasodilation; Vasopressins

Prolonged social subjugation produces physiological indices of chronic stress in rats. In the current study, we examined the impact of social stress on glutamic acid decarboxylase (GAD) isoforms, corticotropin-releasing hormone (CRH) and vasopressin mRNA expression in forebrain stress circuitry, using the visible burrow system model of dominance-subordination. Subordinate male rats develop behavioral and neuroendocrine changes consistent with exposure to chronic stress, including marked loss of body weight and elevation of basal plasma corticosterone relative to dominant rats. Forebrain GAD65, GAD67, CRH and vasopressin mRNA expression in central stress-regulatory circuits were examined by in situ hybridization. Elevated CRH mRNA was observed in the oval nucleus of the bed nucleus of the stria terminalis (BST) of subordinate males. In contrast, GAD67 expression was decreased in the interfascicular nucleus of the BST in both the subordinate and dominant rats compared to non-burrow control rats. No changes in CRH, GAD or vasopressin were observed in amygdaloid nuclei, other BST nuclei or in the hypothalamic paraventricular nucleus. Collectively, these data suggest that exposure to the visible burrow system attenuates BST GAD expression regardless of social status, whereas the enhanced physiological responses to social stress seen in subordinates may be associated with enhanced CRH expression in the oval nucleus of the BST.

Topics: Adrenal Glands; Analysis of Variance; Animals; Behavior, Animal; Body Weight; Corticosterone; Corticotropin-Releasing Hormone; Dominance-Subordination; Female; Gene Expression Regulation; Glutamate Decarboxylase; In Situ Hybridization; Male; Organ Size; Radioimmunoassay; Rats; Rats, Long-Evans; RNA, Messenger; Septal Nuclei; Stress, Psychological; Thymus Gland; Vasopressins

Diabetes is associated with increased basal hypothalamo-pituitary-adrenal (HPA) activity and impaired stress responsiveness. Previously, we demonstrated that the HPA response to hypoglycemia is significantly impaired in diabetic rats. In this study our goals were to 1) differentiate between the effects of hyperinsulinemia and those of hypoglycemia per se, and 2) establish whether diabetes lowers peak stress responses. Normal and streptozotocin-diabetic rats were subjected to hyperinsulinemic-euglycemic glucose clamps to evaluate central and peripheral responses. These were compared with peak ACTH and corticosterone responses to restraint and hypoglycemia. Hyperinsulinemia increased CRH and vasopressin mRNA, and plasma ACTH and corticosterone in normal and diabetic rats. In normal animals, insulin-induced activation of ACTH and corticosterone was lower than the responses during either restraint or hypoglycemia. In contrast, ACTH and corticosterone activation in diabetic rats was similar with all three stressors. Pituitary-adrenal axis activation in diabetic animals was also much lower compared with that in normal controls. The response to hyperinsulinemia (euglycemia) was associated with increases in glucocorticoid receptor mRNA in the anterior pituitary and paraventricular nucleus. Hippocampal mineralocorticoid receptor mRNA expression was increased in normal, but not in diabetic, animals. We speculate that the ability to appropriately match the HPA response to the potency of a stressor is related to the ability to alter hippocampal mineralocorticoid receptor expression. In diabetes, this ability is impaired; hence, maximal HPA activation is greatly diminished. This is a novel observation that may have important implications in the treatment of impaired counterregulatory mechanisms in human diabetes.

Topics: Adrenal Cortex Hormones; Adrenocorticotropic Hormone; Animals; Body Weight; Catecholamines; Corticosterone; Corticotropin-Releasing Hormone; Densitometry; Diabetes Mellitus, Experimental; Hippocampus; Hormones; Hypothalamus; In Situ Hybridization; Insulin; Male; Pituitary-Adrenal System; Rats; Rats, Sprague-Dawley; RNA, Messenger; Stress, Physiological; Time Factors; Vasopressins

In this study, we examined the effects of restricted feeding and of central administration of an orexigenic ghrelin agonist GHRP-6 on peptide mRNA expression in the hypothalamus. We compared rats fed ad libitum with rats that were allowed food for only 2?h every day, and treated with a continuous chronic i.c.v. infusion of GHRP-6 or vehicle. Ad libitum fed rats exposed to GHRP-6 increased their food intake and body weight over 6 days, but, at the end of this period, neuropeptide Y mRNA expression in the arcuate nucleus was not different to that in control rats. By contrast, expression of neuropeptide Y mRNA in the arcuate nucleus was elevated in food-restricted rats, consistent with the interpretation that increased expression reflects increased hunger. However, neuropeptide Y mRNA expression was no greater in food-restricted rats infused with GHRP-6 than in food-restricted rats infused with vehicle; thus if the drive to eat was stronger in rats infused with GHRP-6, this was not reflected by higher levels of neuropeptide Y mRNA expression. Expression of vasopressin mRNA and corticotrophin releasing factor (CRF) mRNA in the paraventricular nucleus (PVN) was not changed by food restriction. GHRP-6 infusion increased CRF mRNA expression in ad libitum rats only.

Topics: Animals; Arcuate Nucleus of Hypothalamus; Body Weight; Caloric Restriction; Corticotropin-Releasing Hormone; Drinking; Eating; Gene Expression; Injections, Intraventricular; Male; Neuropeptide Y; Oligopeptides; Paraventricular Hypothalamic Nucleus; Rats; Rats, Sprague-Dawley; RNA, Messenger; Stress, Physiological; Vasopressins

Experiments were performed to study the physiological regulation of angiotensin (Ang) AT1b receptors using Ang AT1a knockout mice (AT1aKO). Ang AT1b mRNA was analyzed in forebrain, hypothalamus, and brainstem using in situ hybridization (ISH) under baseline and water-restricted conditions. Plasma was analyzed for osmolality, vasopressin, and corticosterone. Dehydration (24 h) increased osmolality and corticosterone and decreased body weight with no difference between groups. Plasma vasopressin was not different between the groups and was not stimulated by dehydration. Under water ad libitum conditions, there were no differences in AT1b mRNA expression in medial periventricular, anterior third ventricle (AV3V), and subfornical organ (SFO) between controls and AT1aKO. In contrast, there was higher expression in the dorsal motor nucleus of the vagus (DMV) of AT1aKO vs. Controls (0.6 +/- 0.1 vs. 0.9 +/- 0.1 microCi/g, Control vs. AT1aKO in water ad libitum group). Dehydration increased AT1b expression in SFO in AT1aKO, but not in controls (0.6 +/- 0.07 vs. 0.9 +/- 0.06 microCi/g; water ad libitum vs. dehydrated). Emulsion autoradiography documents the detailed pattern of AT1b expression in brainstem of controls and AT1aKO. There was labeling in DMV, locus coeruleus, inferior olive, lateral reticular nucleus, and caudalis spinal trigemius. In conclusion, deletion of AT1a receptors produces a compensatory increase in AT1b receptor mRNA expression in brainstem, but not in hypothalamus or rostral forebrain. In addition, AT1aKO mice showed an enhanced response to dehydration in terms of AT1b mRNA expression in SFO.

Topics: Analysis of Variance; Animals; Body Weight; Brain; Corticosterone; Gene Expression Regulation; In Situ Hybridization; Mice; Mice, Knockout; Osmolar Concentration; Radioimmunoassay; Receptor, Angiotensin, Type 1; RNA, Messenger; Vasopressins; Water Deprivation

Estrogen receptor-beta (ER-beta) expression in rat magnocellular vasopressin (VP) neurons of the supraoptic and paraventricular nuclei (SON and PVN, respectively) becomes undetectable after 72 h of 2% NaCl consumption. To test the hypothesis that osmosensitive mechanisms that originate in the region of the organum vasculosum lamina terminalis (OVLT) control ER-beta expression in the SON and PVN, animals were water deprived after electrolytic lesions were performed on the area anterior to the ventral third ventricle (AV3V). Such lesions prevent osmotic stimulation of VP release. Four weeks after surgery, male rats [lesioned (n = 16) or sham (n = 14)] were water deprived for 48 h or allowed water ad libitum. Water deprivation eliminated ER-beta-immunoreactivity (-ir) in SON and magnocellular PVN of sham-lesioned animals. Fos-ir was evident in these neurons, and plasma osmolality (Posm) and hematocrit (Ht) were significantly elevated compared with the sham-hydrated rats (Posm, 304 +/- 1 vs. 318 +/- 2 mosmol/kgH2O; P < 0.001; Ht, 49.6 +/- 0.6 vs. 55.0 +/- 0.9%; P < 0.001). ER-beta expression was comparable in sham-hydrated, AV3V-hydrated, and 6 of 8 AV3V-dehydrated rats despite significant increases in Posm in both groups (AV3V hydrated, 312 +/- 2; AV3V dehydrated, 380 +/- 10 mosmol/kgH2O; P < 0.001). OVLT was not ablated in the AV3V-dehydrated rats in which ER-beta was depleted. Fos-ir was low or undetectable in SON in the AV3V-hydrated animals despite elevated Posm values. In AV3V-dehydrated rats, Fos-ir was significantly less than in sham-dehydrated animals but was significantly increased compared with the sham-hydrated group. This could reflect activation by nonosmotic parameters that do not inhibit ER-beta expression. These data support the hypothesis that inhibition of ER-beta expression in the SON by osmotic stimulation is mediated by osmoreceptive neurons in the lamina terminalis.

Topics: Animals; Basal Ganglia; Body Weight; Cell Count; Estrogen Receptor beta; Genes, fos; Immunohistochemistry; Male; Neurons; Osmotic Pressure; Paraventricular Hypothalamic Nucleus; Rats; Rats, Sprague-Dawley; Receptors, Estrogen; Supraoptic Nucleus; Third Ventricle; Vasopressins; Water Deprivation; Water-Electrolyte Balance

Twin fetuses experience much higher rates of perinatal mortality/morbidity than age- and weight-matched singletons. Across species, the prepartum increase in fetal plasma cortisol is responsible for maturing a number of systems in preparation for birth and the immediate postnatal period. In sheep, it is known that basal adrenocortical function is delayed in twins relative to singletons. Thus, it could be argued that relative immaturity in twins may explain their increased susceptibility to stress in the perinatal period and their relatively poor perinatal outcome. However, whether adrenocortical responsiveness to stress is also diminished in the twin fetus and whether the fetal cardiovascular, metabolic and endocrine defences to acute stress are comparatively weak in the twin fetus is unknown. This study investigated the effect of twinning on adrenocortical responsiveness to either the physiological stress of acute hypoxaemia or to an exogenous ACTH test, and on the fetal cardiovascular, metabolic and endocrine responses to acute hypoxaemic stress. Twenty Welsh Mountain sheep fetuses were chronically instrumented (1-2% halothane) at 121 +/- 3 days of gestation (term is ca 145 days) with amniotic and vascular catheters and with a transit-time flow probe around a femoral artery. The animals were divided into two groups based upon fetal number (singletons, n= 10; twins, n= 10), as determined at surgery. At 130 +/- 2 days, a 1 h episode of acute, isocapnic hypoxaemia (to reduce carotid P(O(2)) to 12 +/- 1 mmHg) was induced in all fetuses by reducing the maternal inspired O(2) fraction (F(IO(2)); 9% O(2) in N(2)). Fetal cardiovascular variables were recorded at 1 s intervals throughout the experimental protocol and arterial blood samples taken at appropriate intervals for biophysical (blood gases, glucose, lactate) and endocrine (catecholamines, vasopressin, cortisol, ACTH) measures. At 133 +/- 2 days a 2.5 microg bolus dose of synthetic ACTH (Synacthen; Ciba Pharmaceuticals, UK) was injected i.v. into eight of the singleton and six of the twin fetuses to determine adrenocortical steroidogenic sensitivity to exogenous ACTH. Under basal conditions, twins had lower plasma cortisol concentration, arterial blood pressure and femoral blood flow relative to singleton fetuses. Twins responded to acute hypoxaemia with similar pressor and vasopressor responses compared to singleton fetuses. However, the rate pressure product, an index of myocardial work, tended to decr

Topics: Acid-Base Equilibrium; Adrenal Cortex; Adrenocorticotropic Hormone; Animals; Blood Gas Analysis; Body Weight; Catecholamines; Endocrine Glands; Female; Fetus; Hormones; Hydrocortisone; Hypoxia; Organ Size; Pregnancy; Sheep; Stress, Physiological; Twins; Vasopressins

Arginine-vasopressin (AVP) has been proposed to be an important mediator during chronic stress in the regulation of the hypothalamo-pituitary-adrenal axis. In the present study we addressed the role of AVP in maintaining adrenocortical responsiveness during chronic stress using the AVP deficient mutant Brattleboro rat. Heterozygous Brattleboro rats (di/+) served as controls and were compared to homozygous rats (di/di) with diabetes insipidus. Sixty minutes daily restraint was repeated for 5, 8, 11 or 15 days and organ weights, plasma adrenocorticotropin (ACTH) and corticosterone levels and anterior pituitary proopiomelanocortin (POMC) mRNA and ACTH content were measured. The body, adrenal and thymus weight changes induced by chronic stress became significant between 5 and 8 repetition and AVP deficiency had no effect on these parameters. The first indication that AVP has a role to play appears after 11 repetitions. In the di/di group at the end of 11th restraint, the plasma ACTH was decreased when compared to the di/+ rats. In animals with indwelling cannulas some adaptation could be seen in ACTH response without any difference between di/+ and di/di rats after 15 restraints. The corticosterone- and prolactin-elevations induced by restraint did not habituate in the di/+ and the di/di rats. Chronic stress increased POMC mRNA in the anterior pituitary similarly in di/+ and di/di rats. Although AVP seems to be necessary for a full ACTH response, most of the other signs of chronic stress after repeated restraint occur unchanged in the absence of AVP in both genders. This suggests that either AVP is not indispensable for activating the hypothalamo-pituitary-adrenocortical system by chronic stress or the absence of AVP is compensated by other mediators in Brattleboro rats.

Topics: Adrenocorticotropic Hormone; Analysis of Variance; Animals; Blotting, Northern; Body Weight; Corticosterone; Female; Hypothalamo-Hypophyseal System; Male; Organ Size; Pituitary Gland; Pituitary-Adrenal System; Pro-Opiomelanocortin; Prolactin; Radioimmunoassay; Rats; Rats, Brattleboro; Restraint, Physical; Sex Factors; Stress, Psychological; Thymus Gland; Time Factors; Vasopressins

Anorexia nervosa (AN) has been associated with abnormal osmoregulation and impaired urinary concentrating capacity. Conflicting results suggest that the disorder may be related to hypothalamic dysfunction and/or a primary renal defect. The role of antidepressants, which are increasingly prescribed in AN patients, has not been evaluated.. We analysed renal function as well as electrolyte disturbances and osmoregulation parameters at baseline and following a water deprivation test in 12 well-defined AN patients (all females, 10 taking antidepressants) vs 12 age-matched controls and 11 young female patients taking antidepressants.. In comparison with matched controls, patients with AN were characterized by a significant alteration of osmoregulation both at baseline [lower plasma sodium and osmolality, abnormally high levels of antidiuretic hormone (ADH) and tendency towards more concentrated urine] and after water deprivation (impaired ADH reaction and lower urinary concentrating ability). The AN patients had no electrolyte abnormalities. The two patients with the shortest duration of AN showed a normal urinary concentrating ability. Patients taking antidepressants showed similar but less marked changes than AN patients, including a lower urinary concentrating ability.. These results show that AN patients are characterized by abnormal osmoregulation at baseline and a lack of reactivity of ADH with a significant urinary concentrating defect after water deprivation. The origin of these defects in AN patients is probably multifactorial, but the duration of the disease and the prescription of antidepressants could play a role.

Topics: Adult; Anorexia Nervosa; Antidepressive Agents; Body Height; Body Mass Index; Body Weight; Case-Control Studies; Female; Humans; Vasopressins; Water-Electrolyte Balance

We sought to determine the effects of a combination of vasopressin and epinephrine on neurologic recovery in comparison with epinephrine alone and saline placebo alone in an established porcine model of prolonged cardiopulmonary resuscitation (CPR). After 4 min of cardiac arrest, followed by 3 min of basic life support CPR, 17 animals were randomly assigned to receive, every 5 min, either a combination of vasopressin and epinephrine (vasopressin [IU/kg]/epinephrine [ micro g/kg]: 0.4/45, 0.4/45, and 0.8/45; n = 6), epinephrine alone (45, 45, and 200 micro g/kg; n = 6), or saline placebo alone (n = 5). After 22 min of cardiac arrest, including 18 min of CPR, defibrillation was attempted to achieve the return of spontaneous circulation. Aortic diastolic pressure was significantly (P < 0.01) increased 90 s after each of 3 vasopressin/epinephrine injections versus epinephrine alone versus saline placebo alone (mean +/- SEM: 69 +/- 3 mm Hg versus 45 +/- 3 mm Hg versus 29 +/- 2 mm Hg, 63 +/- 4 mm Hg versus 27 +/- 3 mm Hg versus 23 +/- 1 mm Hg, and 52 +/- 4 mm Hg versus 21 +/- 3 mm Hg versus 16 +/- 3 mm Hg, respectively). Spontaneous circulation was restored in six of six vasopressin/epinephrine pigs, whereas six of six epinephrine and five of five saline placebo pigs died (P < 0.01). Neurologic evaluation 24 h after successful resuscitation revealed only an unsteady gait and was normal 5 days after the experiment in all vasopressin/epinephrine-treated animals. In conclusion, in this porcine model of prolonged CPR, repeated vasopressin/epinephrine administration, but not epinephrine or saline placebo alone, ensured long-term survival with full neurologic recovery.. We present a study to evaluate the effects of a combination of vasopressin and epinephrine during prolonged cardiopulmonary resuscitation on neurological outcome in pigs. We found that all pigs treated with a combination of vasopressin and epinephrine could be resuscitated and had full neurologic recovery observed over an entire period of 5 days.

Topics: Animals; Blood Gas Analysis; Blood Pressure; Body Weight; Cardiopulmonary Resuscitation; Drug Combinations; Electric Countershock; Electrocardiography; Epinephrine; Heart Arrest; Hemodynamics; Lactic Acid; Nervous System Diseases; Survival; Swine; Vasoconstrictor Agents; Vasopressins; Ventricular Fibrillation

The vasopressin (VP) magnocellular neurosecretory cells (MNCs) in the supraoptic and paraventricular (PVN) nuclei are regulated by estrogen and exhibit robust expression of estrogen receptor (ER)-beta. In contrast, only approximately 7.5% of oxytocin (OT) MNCs express ER-beta. We examined the osmotic regulation of ER-beta mRNA expression in MNCs using quantitative in situ hybridization histochemistry. Hyper-osmolality induced via 2% hypertonic saline ingestion significantly decreased, whereas sustained hypo-osmolality induced via d-d-arginine VP and liquid diet increased ER-beta mRNA expression in MNCs (p < 0.05). Thus, the expression of ER-beta mRNA correlated inversely with changes in plasma osmolality. Because hyper-osmolality is a potent stimulus for VP and OT release, this suggests an inhibitory role for ER-beta in MNCs. Immunocytochemistry demonstrated that the decrease in ER-beta mRNA was translated into depletion of receptor protein content in hyper-osmotic animals. Numerous MNCs were positive for ER-beta in control animals, but they were virtually devoid of ER-beta-immunoreactivity (IR) in hyper-osmotic animals. The osmotically induced decrease in ER-beta expression was selective for MNCs because ER-beta-IR remained unaltered in PVN parvocellular neurons. Plasma estradiol and testosterone were not correlated with ER-beta mRNA expression after osmotic manipulation, suggesting that ER-beta expression was not driven by ligand availability. Expression of FOS-IR in MNCs with attenuated ER-beta-IR, and the absence of FOS-IR in parvocellular neurons that retain ER-beta-IR suggest a role for neuronal activation in the regulation of ER-beta expression in MNCs. Thus, osmotic modulation of ER-beta expression in MNCs may augment or attenuate an inhibitory effect of gonadal steroids on VP release.

Topics: Animals; Blood Volume; Body Weight; Estrogen Receptor beta; Hematocrit; Hormones; Hypernatremia; Hyponatremia; Male; Neurons; Osmolar Concentration; Osmotic Pressure; Oxytocin; Paraventricular Hypothalamic Nucleus; Rats; Rats, Sprague-Dawley; Receptors, Estrogen; Sodium Chloride; Supraoptic Nucleus; Vasopressins; Water-Electrolyte Balance; Water-Electrolyte Imbalance

This study examined the role of the diagonal band of Broca (DBB) in drinking behaviour and vasopressin release. Adult male rats were anaesthetized (pentobarbital 50 mg/kg) and received DBB injections of either ibotenic acid (0.5 microl of 5 micro g/ microl) or vehicle (0.5 microl of phosphate-buffered saline). Although baseline drinking and urine output were not affected, drinking to 30% polyethylene glycol (MW 8000; 1 ml/100 g s.c.) and angiotensin II (0, 1.5 and 3.0 mg/kg s.c.) were significantly increased in ibotenic acid in phosphate-buffered saline (DBBX) rats. Drinking to hypertonic saline (0.9, 4 and 6%; 1 ml/100 g), and water deprivation were not significantly affected. DBBX rats had significantly lower basal heart rates than controls but the cardiovascular responses to infusions of angiotensin II (100 ng/kg/min i.v. for 45 min) were not affected. DBBX rats had significantly higher basal vasopressin, but angiotensin-stimulated vasopressin release was not significantly different. Although the DBB is not involved in basal water intake, it is involved in dipsogenic responses to hypovolemic stimuli and possibly basal autonomic function and basal vasopressin release.

Topics: Angiotensin II; Animals; Blood Pressure; Body Weight; Diagonal Band of Broca; Drinking; Eating; Excitatory Amino Acid Agonists; Heart Rate; Hypertonic Solutions; Ibotenic Acid; Image Processing, Computer-Assisted; Male; Polyethylene Glycols; Rats; Rats, Long-Evans; Vasopressins; Water Deprivation

Impaired regulation of salt and water balance in left ventricular dysfunction and heart failure can lead to pulmonary and peripheral edema and hyponatremia. Previous studies of disordered water regulation in heart failure have used models of low cardiac output with normal cardiac function (e.g., inferior vena cava ligation). We investigated thirst and vasopressin (AVP) secretion in a rat myocardial infarction model of chronic left ventricular dysfunction/heart failure in response to a 24-h water deprivation period. Thirst (implied from water drunk), hematocrit, plasma renin activity, and plasma AVP concentrations increased with water deprivation vs. ad libitum water access. Thirst and plasma AVP concentrations were significantly positively correlated with infarct size after 24-h water deprivation but not under ad libitum water access conditions. The mechanism by which this occurs is unclear but could involve increased osmoreceptor sensitivity, altered stimulation of baroreceptors, the renin-angiotensin system, or altered central neural control.

Topics: Animals; Body Weight; Disease Models, Animal; Heart Failure; Myocardial Infarction; Organ Size; Rats; Rats, Sprague-Dawley; Thirst; Vasopressins; Ventricular Dysfunction, Left; Water Deprivation; Water-Electrolyte Balance

Oestrogens affect fluid balance, influencing both ingestive behaviour and renal excretion. The renal effects are partly due to altered release of vasopressin and oxytocin. This study was designed to explore the role of oestrogen receptor-beta (ERbeta) in neurohypophysial hormonal function. Following dietary administration, soya isoflavones reach the brain in sufficient concentration to activate ERbeta, but not oestrogen receptor-alpha (ERalpha). ERbeta function was therefore manipulated by feeding rat diets differing in soya isoflavone content. Fluid balance and neurohypophysial hormone release were measured in male rats maintained for 14 days on a soya isoflavone-free diet or one containing 150 microg/g genistein+daidzein. Food and water intake, body weight, urine flow, osmolality and sodium concentrations were determined daily. After 14 days, plasma and urine osmolality and sodium, vasopressin and oxytocin concentrations were determined. There was no significant difference in weight gain between the two groups or in their excretion of sodium and water or plasma sodium and plasma oxytocin. However, plasma vasopressin was significantly lower in the iso-free group. Double-label immunocytochemistry was used to assess colocalisation of ERbeta with the neurohypophysial hormones in male rats. Cell nuclei showing ERbeta immunoreactivity were abundant in the posterior magnocellular paraventricular nucleus (PVNpm) and in the supraoptic nucleus (SON). Vasopressin-immunoreactive neurones were similarly distributed, forming the core of the PVNpm and the ventral portion of the SON; majority were positive for ERbeta. Cells with oxytocin immunoreactivity were located mainly at the periphery of the PVNpm and in the dorsal SON; only approximately a quarter of these cells showed ERbeta immunoreactivity. Thus, the difference in the effects of the soya diet on vasopressin and oxytocin release may be related to the ERbeta-activating properties of this diet and to the preponderance of this receptor in vasopressin as opposed to oxytocin cells.

Topics: Animals; Body Weight; Diet; Drinking; Eating; Estrogen Receptor beta; Female; Glycine max; Immunohistochemistry; Male; Osmolar Concentration; Oxytocin; Paraventricular Hypothalamic Nucleus; Pituitary Gland, Posterior; Pituitary Hormones, Posterior; Rats; Receptors, Estrogen; RNA, Messenger; Supraoptic Nucleus; Vasopressins; Water-Electrolyte Balance

Dehydration, a classic homeostatic stressor in rats, leads to a series of well characterized endocrine responses including stimulation of the hypothalamo-pituitary-adrenal (HPA) axis. In this study, the hypothesis to be tested was that a 50% maternal food restriction (FR50) in late gestation and lactation may have long-term repercussions on HPA axis responsiveness to dehydration in offspring. For this purpose, we studied HPA axis activity in 4-month-old control (C) and perinatally malnourished male rats after a 72-hour water deprivation period. Furthermore, we investigated the long-lasting effects of perinatal maternal malnutrition on the basal activity of the HPA axis. Under basal conditions, rats exposed to perinatal malnutrition showed reduced body weight, enhanced mineralocorticoid receptor (MR) mRNA levels in CA2 and CA3 hippocampal areas, but decreased glucocorticoid receptor (GR) mRNA levels in CA1, CA3 and dentate gyrus (DG) areas. In contrast, the levels of corticotropin-releasing hormone (CRH) and vasopressin (VP) mRNAs in the hypothalamic paraventricular nucleus (PVN) as well as of VP mRNA in the supraoptic nucleus (SON) were unaffected by maternal undernutrition. Expression of proopiomelanocortin (POMC) in the adenohypophysis was significantly enhanced, whereas prohormone convertase-1 (PC1) was not affected. Perinatal malnutrition reduced absolute adrenal weight but did not affect circulating levels of adrenocorticotropin (ACTH), corticosterone and free corticosterone as well as corticosteroid-binding globulin (CBG) binding capacity. Seventy-two hours of dehydration induced a decrease in body weight and CRH mRNA levels in PVN of controls as well as of FR50 rats, but also led to a rise in plasma corticosterone and free corticosterone without changing CBG binding capacity. Dehydration also induced an increase in adenopituitary POMC (C) and PC1 (FR50), PVN and SON VP (C) and GR in CA1 hippocampal area (FR50) mRNA levels and plasma ACTH (C), but a decrease in MR in DG (C) and GR in CA3 and DG (C) mRNA levels. We conclude that maternal food restriction during the perinatal period affects (1) the adult basal activity of the HPA axis with mainly opposite effects on hippocampal MR and GR gene expression and an increase in adenopituitary POMC gene expression, and (2) the responsiveness to water deprivation in adults. In the latter case, the rise in plasma ACTH levels, adenopituitary POMC gene expression, hypothalamic VP gene expression, and the decreas

Topics: Adrenal Glands; Animals; Animals, Newborn; Aspartic Acid Endopeptidases; Blood; Body Weight; Dehydration; Female; Food Deprivation; Hormones; Hypothalamo-Hypophyseal System; Hypothalamus; Male; Organ Size; Pituitary Gland, Anterior; Pituitary-Adrenal System; Pregnancy; Prenatal Exposure Delayed Effects; Pro-Opiomelanocortin; Proprotein Convertases; Rats; Rats, Wistar; Receptors, Glucocorticoid; Receptors, Mineralocorticoid; Transcortin; Vasopressins

The first aim of this work was to investigate, under basal conditions in adult male rats, the long-term consequences of perinatal maternal food restriction on the plasma concentrations of vasopressin (VP), aldosterone and atrial natriuretic peptide (ANP) and on plasma renin activity (PRA). Furthermore, under these same conditions, the hypothalamic VP gene expression as well as the density (B(max)), affinity (K(d)) and gene expression of ANP receptors were determined in kidneys and adrenals. The second aim of this work was to examine the responsiveness to dehydration in perinatally malnourished rats. Thus, the latter parameters were studied in these rats after 72 h water deprivation.. This study was conducted on 4-Month-old male rats from mothers exposed to 50% food restriction (FR50) during the last week of gestation and lactation and on age-matched control animals (C). At this stage, both C and FR50 rats were killed by decapitation between 0900 h and 1000 h in order to determine parameters under basal conditions or after 72 h water deprivation. Plasma VP, ANP and aldosterone levels and PRA were determined by radioimmunoassay. Hypothalamic VP gene expression was determined in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) by in situ hybridization. The B(max) and K(d) values of ANP receptors were evaluated from Scatchard plots. ANP receptor gene expression was determined by Northern blot analysis.. Under basal conditions, perinatal malnutrition reduced body weight, absolute weight of kidneys and adrenals, and haematocrit. Compared with control rats, FR50 rats had significantly greater plasma VP and aldosterone levels but PRA, plasma ANP levels, plasma osmolality and hypothalamic VP gene expression were not significantly different. Perinatal malnutrition did not significantly affect glomerular ANP receptor density, but in adrenals it decreased both B(max) and K(d) values of ANP-B receptors (biological receptors) and increased B(max) of ANP-C receptors (clearance receptors). ANP-B(A) (receptor subtype A of ANP-B receptors) receptor gene expression was not significantly affected, whereas ANP-C receptor gene expression was enhanced in both adrenals and kidneys in FR50 rats. After 72 h dehydration, control rats showed a significant rise in haematocrit, plasma osmolality, PRA, circulating levels of VP and aldosterone and VP gene expression in both PVN and SON but showed a decrease in plasma ANP levels. B(max) of ANP-B receptors was decreased whereas B(max) of ANP-C receptors was enhanced in both adrenals and kidneys. ANP-B(A) receptor gene expression was not significantly affected in either kidneys or adrenals in dehydrated control rats. Similarly, ANP-C receptor gene expression was unaffected in kidneys whereas it was significantly enhanced in adrenals. In FR50 rats, the effects of water deprivation were qualitatively similar to those reported in controls concerning plasma parameters except for plasma VP levels which tended to rise (not significant) but this increase was only very slight compared with controls. Moreover, unlike controls, VP gene expression in both PVN and SON was not enhanced after dehydration in FR50 rats. In kidneys, dehydrated FR50 rats, like controls, upregulated ANP-C receptors, but they were unable to downregulate ANP-B receptors. In adrenals, unlike controls, FR50 rats enhanced ANP-B receptor density whereas they decreased both ANP-C receptor density and expression after 72 h dehydration. Similar to controls, the expression of ANP-B(A) receptors in both kidneys and adrenals as well as the expression of ANP-C receptors in kidneys, were unaffected in dehydrated FR50 rats.. Perinatal malnutrition had long-lasting effects on regulation of the fluid and electrolyte balance under basal conditions. The main effects were a significant rise in circulating levels of VP and aldosterone, and changes in density of adrenal ANP-binding sites and ANP-C receptor gene expression in both adrenals and kidneys. Perinatal malnutrition also affects the responsiveness to water deprivation with alterations in both hypothalamic VP gene expression and regulation of ANP-binding sites.

Topics: Adrenal Glands; Animal Nutritional Physiological Phenomena; Animals; Animals, Newborn; Atrial Natriuretic Factor; Binding Sites; Body Weight; Dehydration; Embryo, Mammalian; Endocrine Glands; Hormones; Hypothalamus; Kidney; Male; Nutrition Disorders; Organ Size; Rats; Rats, Wistar; Receptors, Atrial Natriuretic Factor; Tissue Distribution; Vasopressins; Water-Electrolyte Balance

The effects of food restriction on liver glucagon and vasopressin V1a receptors, on AGE accumulation and on gene expression were investigated in 10- and 30-month-old WAG/Rij female rats fed ad libitum or chronically food-restricted by 30%. The age-related increase in glucagon and vasopressin V1a receptor density, as well as the rise in glucagon-induced cAMP generation was prevented by the restriction. AGE accumulation, characteristic of the aging process, was normalized in food-restricted animals. Gene expression determined with rat Atlas cDNA Expression Arrays containing 1176 cDNA indicates that a few genes exhibited a greater than twofold change in mRNA ratios with age. Most down-regulated genes were related to oxidative metabolism of lipids, and most of the up-regulated genes were concerned with the cell cycle and transcription factors. Chronic food restriction partially prevents these changes in gene expression and induces up- and down-regulation of several mRNAs which are not modified with age in ad libitum fed rats.

Topics: Aging; Angiotensin II; Animals; Body Weight; Cells, Cultured; Cyclic AMP; Female; Food Deprivation; Gene Expression; Glucagon; Glycation End Products, Advanced; Hepatocytes; Liver; Organ Size; Rats; Rats, Wistar; Signal Transduction; Vasopressins

Hypokinesia (decreased motor activity) induces significant morphological changes in the kidneys, but little is known about the effect of hypokinesia (HK) on the collecting duct nuclei of the kidney. The aim of this study was to measure the effect of prolonged HK on the nuclear size in the inner meduallary collecting ducts on the kidney of rats. Studies were done on one hundred ninety-two 13-week-old male rats (370 to 390 g) during 15 days pre HK period and 90 days HK period. Rats were equally divided into two groups: vivarium control rats (VCR) and hypokinetic rats (HKR). The HKR group kept in small individual cages. Nuclear size in renal collecting tubules, fluid excretion, sodium (Na) and potassium (K) in plasma and urine, plasma aldosterone (PA) and antidiuretic hormone (ADH) and body weight were measured. A significant (p < or = 0.01) increase in size of the collecting duct nuclei of the kidney, PA, plasma and urinary Na and K and fluid loss, and a significant (p < or = 0.01) decrease of body weight and plasma ADH observed in the HKR group when compared with the VCR. The measured parameters did not change significantly in the VCR group when compared with their baseline control values. It was concluded that prolonged HK induces a significant increase of the nuclear size in the inner meduallary collecting ducts of the kidney of hypokinetic rats when compared with the control rats.

Topics: Animals; Body Weight; Cell Nucleus; Electrolytes; Hypokinesia; Kidney Tubules; Male; Rats; Rats, Sprague-Dawley; Vasopressins; Water-Electrolyte Balance

Mice lacking AT(1A) receptors for ANG II have a defect in urinary concentration manifested by an inability to increase urinary osmolality to levels seen in controls after thirsting. This defect results in extreme serum hypertonicity during water deprivation. In the basal state, plasma vasopressin levels are similar in wild-type controls and Agtr1a -/- mice. Plasma vasopressin levels increase normally in the AT(1A) receptor-deficient mice after 24 h of water deprivation, suggesting that the defect in urine concentration is intrinsic to the kidney. Using magnetic resonance microscopy, we find that the absence of AT(1A) receptors is associated with a modest reduction in the distance from the kidney surface to the tip of the papilla. However, this structural abnormality seems to play little role in the urinary concentrating defect in Agtr1a -/- mice since the impairment is largely reproduced in wild-type mice by treatment with an AT(1)-receptor antagonist. These studies demonstrate a critical role for the AT(1A) receptor in maintaining inner medullary structures in the kidney and in regulating renal water excretion.

Topics: Angiotensin Receptor Antagonists; Animals; Body Weight; Deamino Arginine Vasopressin; Female; Genotype; Kidney; Kidney Concentrating Ability; Losartan; Male; Mice; Osmolar Concentration; Receptor, Angiotensin, Type 1; Receptors, Angiotensin; Urine; Urodynamics; Vasopressins; Water; Water Deprivation

The two genes coding for thyroid hormone receptors (TR) alpha 1 and beta have opposite effects on female sex behaviors. Deletion of TRalpha 1 reduced them, whereas deletion of TRbeta actually increased them. These results could not be attributed to altered levels of hormones in the blood, general alterations in estrogen responsiveness or altered general activity. Instead, they indicate a previously unknown molecular mechanism upon which the two TR genes exert opposite influences.

Topics: Animals; Body Weight; Estradiol; Estrogens; Female; Gene Deletion; Male; Mice; Mice, Inbred Strains; Mice, Knockout; Organ Size; Oxytocin; Paraventricular Hypothalamic Nucleus; Posture; Preoptic Area; Progesterone; Receptors, Estrogen; Receptors, Thyroid Hormone; Sexual Behavior, Animal; Thyroxine; Triiodothyronine; Uterus; Vasopressins

The mechanisms underlying age-related polyuria were investigated in 10- and 30-mo-old female WAG/Rij rats. Urinary volume and osmolality were 3.9 +/- 0.3 ml/24 h and 2,511 +/- 54 mosmol/kgH(2)O in adult rats and 12.8 +/- 0.8 ml/24 h and 1,042 +/- 44 mosmol/kgH(2)O in senescent animals. Vasopressin V(2) receptor mRNA did not significantly differ between 10 and 30 mo, and [(3)H]vasopressin binding sites in membrane papilla were reduced by 30%. The cAMP content of the papilla was unchanged with age, whereas papillary osmolality was significantly lowered in senescent animals. The expression of aquaporin-1 (AQP1) and -4 was mostly unaltered from 10 to 30 mo. In contrast, aquaporin-2 (AQP2) and -3 (AQP3) expression was downregulated by 80 and 50%, respectively, and AQP2 was markedly redistributed into the intracellular compartment, in inner medulla of senescent animals, but not in renal cortex. These results indicate that age-related polyuria is associated with a downregulation of AQP2 and AQP3 expression in the medullary collecting duct, which is independent of vasopressin-mediated cAMP accumulation.

Topics: Aging; Animals; Aquaporin 2; Aquaporin 3; Aquaporin 6; Aquaporins; Binding Sites; Body Weight; Cell Membrane; Cyclic AMP; Down-Regulation; Drinking; Eating; Female; Fluorescent Antibody Technique, Indirect; Kidney; Kidney Medulla; Kidney Tubules; Osmolar Concentration; Polyuria; Rats; Rats, Inbred Strains; Receptors, Vasopressin; RNA, Messenger; Vasopressins

Cisplatin (CP)-induced polyuria in rats is attributed to decreased medullary hypertonicity and/or an end-organ resistance to vasopressin. However, the roles of renal aquaporins (AQPs) have not yet been explored.. Male Sprague-Dawley rats (230 to 245 g) received either a single injection of CP (5 mg/kg, N = 4) or saline (N = 4) intraperitoneally five days before sacrifice. Urine, blood, and kidney samples were analyzed.. Platinum accumulated in the cortex and outer medulla of CP-treated rats (39.05 +/- 7.50 and 36.48 +/- 12.44 microg/g vs. 2.52 +/- 0.43 and 1.87 +/- 0.84 microg/g dry tissue in controls, respectively). Histologically, tubular damage and decreased AQP1 immunolabeling were detected in the S3 segment of proximal tubules. CP treatment caused 4.4- and 4.8-fold increases, respectively, in blood urea nitrogen and urine volume, and a 4. 4-fold decrease in urine osmolality. Immunoblots showed that AQP2 and AQP3 were significantly reduced to 33 +/- 10% (P < 0.001) and 69 +/- 11% (P < 0.05), respectively, in the inner medulla of CP-treated rats. Immunocytochemical analysis showed a decrease in AQP2 labeling in the inner medulla of CP-treated rats. Northern hybridization revealed a 33 +/- 11% (P < 0.002) decrease in AQP2 mRNA expression in the inner medulla of CP-treated rats. AQP1 protein expression levels were modestly (67 +/- 7%, P = 0.057) and significantly (53 +/- 13%, P < 0.007) decreased in outer and inner medullae, respectively, of CP-treated rats.. CP-induced polyuria in rats is associated with a significant decrease in the expression of collecting duct (AQP2 and AQP3) and proximal nephron and microvascular (AQP1) water channels in the inner medulla.

Topics: Animals; Antineoplastic Agents; Aquaporin 1; Aquaporin 2; Aquaporin 3; Aquaporin 6; Aquaporins; Blood Urea Nitrogen; Blotting, Northern; Body Weight; Cisplatin; Disease Models, Animal; Gene Expression; Immunoblotting; Kidney Tubules, Collecting; Kidney Tubules, Proximal; Male; Platinum; Polyuria; Rats; Rats, Sprague-Dawley; RNA, Messenger; Urinalysis; Vasopressins

Antidiuretic actions induced by two growth hormone (GH) isoforms (20 K- and 22 K-hGH; 0.2 and 2.0 mg/kg) were evaluated in rats, as fluid retention may cause oedema, one of the adverse effects of GH. Both GH isoforms (2.0 mg/kg) suppressed urine excretion in hypophysectomized rats (P< 0.01), but only the 22 K-hGH isoform (2.0 mg/kg) suppressed urine excretion in intact rats (P< 0.01). In addition, prolactin (PRL) suppressed urine excretion in intact rats (P< 0.05). In conclusion, 20 K-hGH has less potency in causing urine retention than 22 K-hGH and since 20 K-hGH is missing 15 amino acids found in 22 K-hGH, these amino acids may be important for the antidiuretic action of GH. Since prolactin suppressed urine excretion, a part of the antidiuretic action of GH may be related to PRL-R activation.

Topics: Animals; Body Weight; Diuresis; Edema; Growth; Human Growth Hormone; Humans; Hypophysectomy; Male; Molecular Weight; Pituitary Gland; Prolactin; Rats; Rats, Sprague-Dawley; Recombinant Proteins; Vasopressins; Water-Electrolyte Balance

Holstein bull calves were used to examine the effect of dry feed on water balance and fecal moisture content during the suckling period. In Experiment 1 (n = 20 calves), free access to concentrate and timothy hay decreased urine volume and increased apparent water retention, fecal water excretion, and fecal moisture content by 2 wk, although daily amounts of milk replacer also affected water balance when DMI from dry feed was low. In Experiment 2 (n = 20 calves), free access to concentrate and hay from wk 1 increased reabsorption of water from renal tubules during wk 2, resulting in reduced urine volume and increased plasma volume. In Experiment 3 (n = 10 calves), supplementation of 500 g/d of milk replacer plus free access to concentrate and hay from wk 1 increased plasma antidiuretic hormone by 2 wk compared with the concentration in calves receiving 200 g/d of milk replacer alone. Plasma antidiuretic hormone concentrations were highly correlated with plasma concentrations of acetate and ketone bodies but not with glucose and urea. In Experiment 4 (n = 16 calves), apparent water retention and fecal moisture content during wk 2 were increased by free access to concentrate from wk 1 but were not affected by rice straw as an inert bulk source.

Topics: Acetic Acid; Animal Feed; Animals; Animals, Suckling; Blood; Blood Urea Nitrogen; Body Water; Body Weight; Cattle; Feces; Ketone Bodies; Male; Milk; Osmolar Concentration; Urine; Vasopressins; Water; Water-Electrolyte Balance; Weight Gain

The effect of volume reduction on vasoactive substances and their role in estimating dry weight in haemodialysis patients was studied. Plasma atrial natriuretic peptide (ANP), catecholamines, antidiuretic hormone, renin activity and serum aldosterone were measured in 12 patients before and after bicarbonate haemodialysis. Haemodynamical changes were registered and cardiac function and diameter of the inferior vena cava were measured by echocardiography before and after dialysis. Plasma concentration of ANP was significantly reduced by haemodialysis from 209 +/- 51 to 69 +/- 13 pg mL(-1) (n = 12, P < 0.05), whereas concentrations of the other hormones were unchanged. The change in the concentration of ANP did not have significant correlation with weight reduction. The concentration of ANP correlated positively with the diameter of the inferior vena cava (r = 0.70, P < 0.05) after dialysis, but not before dialysis. The concentration of ANP before or after haemodialysis or its change during dialysis did not correlate with any other biochemical parameter. The results show that plasma ANP level is decreased after volume reduction in patients with chronic renal failure, whereas other hormonal systems are unresponsive. However, plasma concentration of ANP seems to have no role in estimating dry weight in chronic haemodialysis patients.

Topics: Adult; Aged; Aldosterone; Atrial Natriuretic Factor; Body Weight; Catecholamines; Female; Humans; Kidney Failure, Chronic; Male; Middle Aged; Neurotransmitter Agents; Renal Dialysis; Renin; Ultrasonography; Vasopressins

kappa-Opioid receptor agonists (niravoline) or nonpeptide antidiuretic hormone (ADH) V2 receptor antagonists (OPC-31260) possess aquaretic activity in cirrhosis; however, there is no information concerning the effects induced by the chronic administration of these drugs under this condition. To compare the renal and hormonal effects induced by the long-term oral administration of niravoline, OPC-31260, or vehicle, urine volume, urinary osmolality, sodium excretion, and urinary excretion of aldosterone (ALD) and ADH were measured in basal conditions and for 10 days after the daily oral administration of niravoline, OPC-31260, or vehicle to cirrhotic rats with ascites and water retention. Creatinine clearance, serum osmolality, ADH mRNA expression, and systemic hemodynamics were also measured at the end of the study. Niravoline increased water excretion, peripheral resistance, serum osmolality, and sodium excretion and reduced creatinine clearance, ALD and ADH excretion, and mRNA expression of ADH. OPC-31260 also increased water metabolism and sodium excretion and reduced urinary ALD, although the aquaretic effect was only evident during the first 2 days, and no effects on serum osmolality, renal filtration, and systemic hemodynamics were observed. Therefore, both agents have aquaretic efficacy, but the beneficial therapeutic effects of the long-term oral administration of niravoline are more consistent than those of OPC-31260 in cirrhotic rats with ascites and water retention.

Topics: Aldosterone; Animals; Antidiuretic Hormone Receptor Antagonists; Benzazepines; Benzeneacetamides; Body Water; Body Weight; Carbon Tetrachloride Poisoning; Diuretics; Hemodynamics; Hormones; Hypothalamus; Kidney; Liver Cirrhosis, Experimental; Male; Osmolar Concentration; Pyrrolidines; Rats; Rats, Wistar; Receptors, Opioid, kappa; RNA, Messenger; Urodynamics; Vasopressins

The aim of this study was to characterize hemodynamic, electrolytic and endocrine alterations produced by food restriction (50%) in pregnant rats for the purpose of evaluating the importance of these parameters on the plasma volume expansion and fetal growth. One hundred seventy six pregnant rats were divided into two groups, a control group (C) with an ad libitum diet and another with a restricted diet (U) (50% by weight of the diet of the control group). On days 5, 10, 15 and 20 of pregnancy, the weight of the mother, water intake, urine output, urine and plasma sodium concentration, plasma potassium concentration, blood pressure and heart rate, osmolality, plasma renin activity (PRA) and vasopressin were recorded. The number and weight of the fetuses were determined on days 15 and 20 of gestation. Food restriction results in inadequate weight gain in the mother and retardation of fetal growth. Water and sodium balance (p< or =0.001) were decreased in U group and basal PRA (p< or =0.001) was increased in U group. Food restriction did not significantly alter urine sodium excretion, plasma osmolality, plasma sodium and potassium values, blood pressure and basal vasopressin values. We conclude that the higher values of PRA, described in food restriction situations during pregnancy, seem to be caused by the adaptation to low sodium intake.

Topics: Adaptation, Physiological; Animals; Blood Pressure; Body Weight; Endocrine Glands; Female; Fetus; Food Deprivation; Gestational Age; Heart; Natriuresis; Osmolar Concentration; Potassium; Pregnancy; Rats; Rats, Wistar; Renin; Sodium; Sodium, Dietary; Vasopressins; Water-Electrolyte Balance

In diabetes mellitus (DM), the high urine flow rate suggests that urinary concentrating capacity is impaired. However, several studies have shown that vasopressin is elevated in DM and the consequences of this elevation have not yet been characterized. This study reevaluated renal function and water handling in male Wistar rats with Streptozotocin-induced DM, and in control rats. During five weeks after induction of DM, urine was collected in metabolic cages and a blood sample was drawn during the third week. Control rats (CONT) were studied in parallel. On week 3, urine flow rate was tenfold higher in DM than in CONT rats and urinary osmolality was reduced by half along with a markedly higher osmolar excretion (DM/CONT = 5.87), due for a large part to glucose but also to urea (DM/CONT = 2.49). Glucose represented 52% of total osmoles (90.3 +/- 6.5 mmol/d out of 172 +/- 14 mosm/d). Free water reabsorption was markedly higher in DM rats compared to CONT (326 +/- 24 vs 81 +/- 5 ml/d). In other rats treated in the same way, urinary excretion of vasopressin was found to be markedly elevated (15.1 +/- 4.1 vs 1.44 +/- 0.23 ng/d). In DM rats, glucose concentration in urine was 17 fold higher than in plasma, and urea concentration 14 fold higher. Both urine flow rate and free water reabsorption were positively correlated with the sum of glucose and urea excretions (r = 0.967 and 0.653, respectively) thus demonstrating that the urinary concentrating activity of the kidney increased in proportion to the increased load of these two organic solutes. These results suggest that vasopressin elevation in DM contributes to increase urinary concentrating activity and thus to limit water requirements induced by the metabolic derangements of DM. The possible deleterious consequences of sustained high level of vasopressin in DM are discussed.

Topics: Animals; Blood Glucose; Body Weight; Creatinine; Diabetes Mellitus, Experimental; Diuresis; Drinking Behavior; Glucagon; Glycosuria; Kidney Concentrating Ability; Male; Potassium; Rats; Rats, Wistar; Sodium; Urea; Vasopressins

We have previously shown that a chronic reduction in plasma vasopressin level slowed the progression of chronic renal failure (CRF) in Sprague Dawley rats. The aim of the present study was to determine the respective contribution of pressor (V1) and antidiuretic (V2) effects of vasopressin on progression. Male homozygous Brattleboro rats with hereditary central diabetes insipidus were submitted to 5/6 nephrectomy. They were divided into three groups, two of which received chronic i.p. infusion of AVP (V1 + V2 effects) or dDAVP (V2 effects). The third group served as control (CONT). The doses of AVP and dDAVP were chosen so as to produce urine osmolality similar to that observed in 5/6 Nx Sprague Dawley rats. All rats ate the same amount of food and drank water ad libitum. Renal function was studied for 13 weeks. All three groups showed a marked hypertension. Rats infused with dDAVP, but not those infused with AVP, had a higher creatininemia, anemia and urinary protein excretion than CONT rats. In the dDAVP but not the AVP group, fractional excretion of urea was markedly decreased and plasma urea concentration rose much more than that of creatinine. These results show that V2 but not V1 effects play a major role in the deleterious influence of vasopressin on progression, at least in Brattleboro rats. The more severe progression seen in dDAVP rats could indirectly result from the V2-mediated effects on the collecting duct resulting in a decreased efficiency of urea excretion, an increased intrarenal urea recycling, and a rise in plasma urea concentration. Both the toxic effects of urea and the recently demonstrated V2-mediated increase in glomerular hemodynamics might be involved in the deleterious influence of V2 agonism.

Topics: Animals; Arginine Vasopressin; Blood Pressure; Body Weight; Creatinine; Diabetes Insipidus; Disease Models, Animal; Disease Progression; Kidney; Kidney Failure, Chronic; Male; Proteinuria; Rats; Rats, Brattleboro; Rats, Sprague-Dawley; Uremia; Vasopressins

Responses of pituitary concentrations of vasopressin (AVP) and oxytocin (OT) during spaceflight have been variable, possibly due to differences in flight conditions or in age and strain of flight animals.. We reviewed findings of three space-flights of varying flight and recovery durations in which rats of different ages and strains were used. Male rats ranging in weight from 248-396 g were flown in space for 7-14 d. Flight animals were then compared with vivarium controls and synchronous controls. Parallel ground-based studies (hypergravity and simulated hypogravity) were conducted.. Pituitary content of AVP was significantly (p < or = 0.05) decreased by spaceflight (6.3 +/- 0.3 micrograms.mg-1 protein in flight vs. 8.3 +/- 0.5 micrograms.mg-1 protein in vivarium). OT content was also reduced during spaceflight (4.3 +/- 0.2 micrograms.mg-1 protein in flight vs. 6.1 +/- 0.3 micrograms.mg-1 protein in vivarium). Vivarium and synchronous control rats showed no difference in pituitary contents. Flight duration or recovery times did not appear to influence pituitary hormone contents. Strain of rat had an effect on content but not on responses to spaceflight. Age of animals confounded the response to spaceflight: pituitary contents of AVP and OT were not altered in young animals (< or = 60 d old). Hindlimb suspended animals showed no difference in AVP but OT content was decreased. Ground-based exposure to hypergravity (2 G) did not alter content of AVP or OT in young animals.. Decreases in pituitary content of AVP and OT with spaceflight may be due to a variety of factors unique to the microgravity environment. Differences between studies may be due in part to differences in size and age of rats used.

Topics: Age Factors; Animals; Body Mass Index; Body Weight; Confounding Factors, Epidemiologic; Hindlimb Suspension; Hypergravity; Hypogravity; Male; Oxytocin; Pituitary Gland; Random Allocation; Rats; Rats, Sprague-Dawley; Rats, Wistar; Space Flight; Time Factors; Vasopressins

It has been shown that vasopressin receptors are upregulated in the brain and that the central vasopressin pathway is involved in the development of deoxycorticosterone acetate (DOCA)-salt hypertension. However, it is unclear whether central vasopressin, in itself, is essential for this type of hypertension. To clarify this issue, the effect of centrally administered vasopressin on the development of DOCA-salt hypertension was studied in homozygous Brattleboro rats which genetically lack vasopressin. In homozygous Brattleboro rats, treatment with intracerebroventricular infusion of vasopressin (1 ng/h) alone or DOCA-salt (weekly subcutaneous injection of 30 mg/kg deoxycorticosterone acetate and 0.3% NaCl to drink) alone had no effect on systolic blood pressure (SBP). On the other hand, hypertension was partially restored in homozygous Brattleboro rats treated with intracerebroventricular infusion of vasopressin and DOCA-salt (SBP: 175 +/- 4 mmHg), although the magnitude of elevation of SBP was one-third of that in Long Evans rats treated with DOCA-salt (278 +/- 15 mmHg). These hypertensive homozygous Brattleboro rats showed an increase in fluid intake and urinary sodium excretion, as observed in DOCA-salt hypertensive Long Evans rats. These results suggest that central vasopressin is required for the complete development of DOCA-salt hypertension and the mechanism is, in part, due to enhanced sodium intake through the additive effect of central vasopressin and DOCA-salt.

Topics: Animals; Blood Pressure; Body Weight; Desoxycorticosterone; Diabetes Insipidus; Disease Models, Animal; Hypertension; Male; Rats; Vasopressins

Our goal was to study the water balance in healthy breast-fed infants (n = 139) during their first 5 days, by cross-sectional measurements of body weight, serum sodium, serum osmolality, and hematocrit. We also investigated infants' capacity to conserve body water by increased secretion of vasopressin, the main antidiuretic hormone in human beings.. The maximal body weight reduction was 5.7% +/- 1.7% (mean +/- SD) of birth weight and most infants started to gain weight when they were 3 days old. The serum sodium level at 16 +/- 4 hours (on day of birth) was 142 mmol/L; the level increased after 1 day (p < 0.01) and remained constantly high for the following 2 days (p < 0.05). The serum osmolality was increased at 1 day (p < 0.01) and 2 days (p < 0.05) compared with the value on the day of birth (296 mOsm/kg). The plasma vasopressin level was constant up to 24 hours (1 day), but decreased during the next 2 days (p < 0.01). Infants with body weight reduction exceeding 10% (n = 15) had a further elevation of the serum sodium level (p < 0.0001) and serum osmolality (p < 0.0001), and the plasma vasopressin level was twofold higher (p < 0.0001) compared with corresponding levels in infants with less weight reduction. These infants also had a reduced interval between two subsequent feedings (p < 0.001). The hematocrit remained unchanged irrespective of the degree of weight reduction.. When the reduction of body weight exceeds 10%, the newborn infant releases vasopressin in response to fluid hypertonicity. This state also affects feeding behavior, perhaps as an expression of thirst. It is likely that hormone release is also stimulated in parallel with a weight reduction of less than 10%, because it is also accompanied by a hyperosmotic state.

Topics: Body Weight; Cross-Sectional Studies; Dehydration; Female; Hematocrit; Humans; Infant, Newborn; Male; Osmolar Concentration; Plasma; Sodium; Thirst; Vasopressins; Water-Electrolyte Balance; Weight Loss

The question of whether the coronary vasospasm induced by intravenous administration of vasopressin produces any remodeling of the capillary network in the left ventricle was investigated. To this end, cardiac tissues obtained from vasopressin-injected rats were stained to allow capillary counting and for basic fibroblast growth factor (bFGF).. Nine male Donryu rats were divided into three groups that received, respectively, 0.25 ml of saline containing 0, 0.5, or 1.0 U/kg vasopressin injected into the tail vein once daily for 4 days. Rats were killed 30 days after the last injection. Two additional rats each received a single intravenous injection of 1.0 U/kg vasopressin and were killed 24 hours later. The left ventricles were removed and 16- or 10-micron frozen sections were cut for differential staining and distribution of bFGF, respectively. Differential staining was used to classify the capillary portions, and bFGF was identified by immunohistological staining.. Compared with the control group, total capillary density was increased in both vasopressin-treated groups, capillary to myocyte ratio was increased, and the capillary domain areas decreased in the three capillary portions. Arteriolar and intermediate capillary portions increased, while the venular capillary portion decreased. In rats killed 24 hours after vasopressin injection, a considerable amount of bFGF could be demonstrated immunohistochemically in the ventricular tissues, and the punctate distribution of bFGF was still found in rats killed 30 days after treatment.. A remodeling of capillary network which would increase the oxygen transport capacity to cardiac tissues was produced in left ventricular tissues by intravenous injection of vasopressin. bFGF located around capillaries and in the interstitial space may have been involved in the capillary remodeling.

Topics: Animals; Body Weight; Capillaries; Coronary Circulation; Coronary Vasospasm; Drug Administration Schedule; Heart Ventricles; Injections, Intravenous; Male; Organ Size; Rats; Rats, Inbred Strains; Vasopressins; Ventricular Function

Water intake following dehydration was studied in pregnant (N = 5), lactating (N = 4) and nonpregnant, nonlactating (N = 5) Swedish domestic goats (Capra hircus) to investigate if reproductive period affected drinking. Plasma cortisol concentration and the hematocrit value were measured to evaluate stress. The goats were water deprived from 9.00 h until 15.05 h the next day. They were fed at 7.00 and 15.20 h. On the second day, ambient temperature was increased from 20 degrees C to 38-39.5 degrees C for 5.15 h to accelerate water losses. Water temperature during rehydration was 35 +/- 1 degree C. Plasma Na concentration and osmolality increased most in dehydrated and heat-stressed pregnant and lactating goats. Pregnant goats lost 2.2 kg of their body weight. They drank 3.5 l immediately, followed by 2.5 l during afternoon eating. Lactating goats lost 4.9 kg and drank 6.3 l at once, and 3.9 l during feeding. Nonpregnant, nonlactating goats lost 1.7 kg and drank 2.6 l followed by 0.6 l. The large water consumption in pregnant and lactating goats caused hyponatremia and hemodilution, but they continued to drink during the night (0.5 +/- 0.2 l and 0.8 +/- 0.5 l, respectively). Renal free water clearance increased in all periods, with a long-lasting water diuresis during pregnancy. Plasma cortisol concentrations and the hematocrit values rose in connection with water intake. These results imply that the thirst center became less sensitive to inhibitory signals from the oropharyngeal tract and the diluted blood plasma during pregnancy and lactation. Catching sight of water was the most exciting procedure during these experiments.

Topics: Animals; Blood Proteins; Body Temperature; Body Weight; Dehydration; Drinking; Female; Goats; Hematocrit; Hot Temperature; Hydrocortisone; Lactation; Pregnancy; Reproduction; Respiration; Sodium; Urination; Vasopressins

The effect of orally available, nonpeptide vasopressin V1 and V2 receptor antagonists on chronic progressive glomerular disease was investigated in Wistar rats with Adriamycin-induced nephropathy. At weeks 0 and 3, Adriamycin was injected twice, and at week 3 drugs started to be given as follows: groups 2 and 3 were treated with V1 and V2 antagonists, respectively, while the untreated group 1 served as control. To block the effects of vasopressin totally, both V1 and V2 antagonists were simultaneously administered (group 4). At weeks 8 and 10, V1 and V2 antagonists given either alone or combined significantly reduced the urinary protein excretion to the same levels. Urinary volume increased in groups 3 and 4 from week 4. Systolic blood pressure did not significantly increase in all groups during the study. Histological alterations in the kidney of groups 2, 3 and 4 were significantly attenuated compared to the control. These results suggest that both vasopressin V1 and V2 agonism plays a role in the pathophysiology of Adriamycin-induced nephropathy despite plasma levels of vasopressin within the normal range. These findings also lead to the notion that in some types of nephrotic patients these orally available V1 and/or V2 receptor antagonists may be effective for reduction of proteinuria and for retardation of progression of renal failure.

Topics: Animals; Antibiotics, Antineoplastic; Blood Pressure; Body Weight; Doxorubicin; Eating; Kidney; Kidney Diseases; Male; Proteinuria; Rats; Rats, Wistar; Receptors, Vasopressin; Vasopressins

To determine the effect of hindlimb suspension on body fluid volume, salt and water balance, and relevant hormones, two series of experiments were performed in an experimental protocol including periods of isolation (7 days), horizontal attachment (7 days), and suspension (14 days). 1) During the first experiment, water and electrolyte balance, arginine vasopressin (AVP), and guanosine 3',5'- cyclic monophosphate (cGMP) were determined in urine, atrial natriuretic peptide in plasma and atria, and renin concentration and AVP in plasma in 30 rats. 2) During the second experiment, blood volume and extracellular fluid volume were measured by a dilution technique (Evans blue and sodium thiocyanate) in another 30 rats. We observed a pronounced and early effect of horizontal attachment on the renal variables. After 48 h, diuresis (49%), natriuresis (44%), kaliuresis (36%), osmotic load (39%), creatinine (28%), and AVP excretion (155%) were significantly increased in attached rats (P < 0.05). There was no short-term (24-h) effect of suspension on urine flow and Na+, K+, creatinine, and AVP excretion, but the urine cGMP decreased significantly (45%; P < 0.05). Significant decreases in natriuresis, kaliuresis, urine creatinine, and osmotic load occurred in the suspension group 7 days after suspension. After the 14-day tail suspension, plasma volume and extracellular fluid volume measured in suspended rats were not different from isolated rat values, whereas plasma volume increased by 15% (P < 0.05) in the attached rats. Plasma immunoreactive plasma atrial natriuretic levels of suspended rats were significantly reduced by 35% vs. isolated rats (P < 0.001) and by 18% vs. attached rats (P < 0.05). By using this experimental protocol, the physiological alterations revealed that suspension produced some acute and long-term effects, but the fixation to the suspension device, restraint, and confinement have their own influence on fluid distribution and renal function.

Topics: Animals; Atrial Natriuretic Factor; Body Water; Body Weight; Electrolytes; Hindlimb; Male; Rats; Rats, Wistar; Vasopressins

Pneumadin (PNM) is a biologically active decapeptide, originally isolated from mammalian lungs, that has been previously found to acutely stimulate pituitary-adrenocortical axis in rats. The effects of 2-day PNM administration on the atrophic adrenal cortices of rats treated for 8 days with dexamethasone (DX) were investigated. PNM significantly raised adrenal weight and the average volume of adrenocortical cells. The decapeptide strikingly increased ACTH plasma concentration; however, the blood levels of aldosterone and corticosterone, as well as steroid output by adrenal quarters were not apparently affected. In light of these findings the following conclusions can be drawn: (i) PNM enhances the growth of adrenal cortex in DX-administered rats by a mechanism involving the stimulation of ACTH release; and (ii) PNM treatment is probably too short to allow DX-atrophied adrenocortical cells to re-acquire all their differentiated secretory capacities.

Topics: Adrenal Cortex; Adrenocorticotropic Hormone; Animals; Anti-Inflammatory Agents; Body Weight; Dexamethasone; Female; Neutrophils; Oligopeptides; Organ Size; Paraffin Embedding; Rats; Rats, Wistar; Stimulation, Chemical; Vasopressins

Factors related to atrial natriuretic peptide (alpha-ANP) regulation and its potential impact on excretory transplant function were examined in a prospective cohort study of 20 patients with end-stage renal disease over 21 days after allogenic kidney transplantation. Depending on posttransplant graft function, patients were separated into those with primary renal function (PF group, n = 10) and posttransplant acute renal failure (ARF group, n = 10). ANP concentrations were markedly elevated in both PF and ARF immediately after renal transplantation, even when compared with the pretransplant dialysis phase (PF group: 939 +/- 467 pg/ml; ARF group: 648 +/- 306 pg/ml, on 3rd postoperative day; "normals': 72 +/- 35 pg/ml). Whilst ANP levels were persistently elevated in patients with acute renal failure, there was a steady decrease in plasma concentrations in patients with primary renal function (PF: 270 +/- 122 pg/ml on 21st day). ANP concentration correlated with endogenous creatinine clearance (rz = 0.56, p < 0.01, PF group). Moreover, there was a greater correlation between ANP levels and postoperative hydration status, measured as central venous pressure or the difference from predialysis dry weight (rz = 0.79 and rz = 0.74, p < 0.01, PF group). Systolic blood pressure was also positively correlated with ANP concentrations. Together, these factors accounted for a total correlation coefficient of r = 0.87 (p < 0.001) in multiple regression analysis. No significant relation was found between plasma ANP levels and total or fractional sodium excretion or free water clearance. With the restoration of renal function most vasoactive hormones (renin-aldosterone system, catecholamines, vasopressin) decreased towards normal values, whilst ANP plasma concentrations remained elevated.

Topics: Adult; Atrial Natriuretic Factor; Blood Pressure; Body Weight; Catecholamines; Central Venous Pressure; Cohort Studies; Creatinine; Cyclic GMP; Female; Humans; Kidney; Kidney Failure, Chronic; Kidney Transplantation; Male; Middle Aged; Postoperative Period; Prospective Studies; Renin; Transplantation, Homologous; Vasopressins

We describe a case of diabetes insipidus (DI) due to a pituitary tumor in a 33-year-old pregnant woman who developed a sudden onset of polyuria (over 8 l/day) and polydipsia at 30 weeks of gestation. Her plasma concentration of vasopressin (AVP) was low compared with high serum osmolality (298 mOsm/kg), and her urine output was well controlled by treatment with desmopressin acetate (DDAVP). Cranial magnetic resonance imaging (MRI) demonstrated a 1.8 x 1.2-cm pituitary tumor, but she did not have any disturbance in the release of anterior pituitary hormones. The serum concentration of cystine aminopeptidase (CAP) was within the normal range for a woman at 34 weeks of gestation. After an uncomplicated delivery of a healthy girl, her polyuria gradually resolved. The size of the pituitary tumor gradually decreased in parallel to a reduction in her urine output, but a silent hemorrhage was detected in her pituitary gland 4 weeks after the delivery. Although pregnancy is sometimes associated with central DI, the occurrence of DI due to pituitary tumor under pregnancy is rare. The basal AVP recovered to within the normal range, but the low response of AVP secretion to high osmolality persisted. In this case, pregnancy may affect the manifestation of subclinical DI. This case may therefore enhance our understanding of the mechanisms of DI during pregnancy.

Topics: Adenoma; Adult; Body Weight; Deamino Arginine Vasopressin; Diabetes Insipidus; Female; Humans; Hypoglycemic Agents; Magnetic Resonance Imaging; Osmolar Concentration; Pituitary Function Tests; Pituitary Gland, Anterior; Pituitary Neoplasms; Pregnancy; Pregnancy Complications; Pregnancy Complications, Neoplastic; Pregnancy Trimester, Third; Time Factors; Urine; Vasopressins

The purpose of this study was to characterize the hormonal responses to a restraining system in four adult male rhesus monkeys (Macaca mulatta) in preparation for a spaceflight project. After the monkeys were accustomed to food and water (Phase I), blood-volume-regulating hormones were measured during three phases: 10 days in a metabolic cage (Phase II), 16 days sitting in a restrained position in a specially designed metabolism chair (Phase III) and 10 days in metabolic cage (Phase IV). An increase of active renin (30%) and vasopressin (25%) was observed at the end of Phase III. A decrease of atrial natriuretic peptide (ANP), urodilatin, and sodium excretion occurred during the first days of Phase III. Catecholamines were unchanged. A dramatic increase (tenfold) in urinary excretion of growth hormone occurred during all of Phase III and at the beginning of Phase IV. These findings are similar to those found in man during isolation inactivity and during confinement stress.

Topics: Aldosterone; Animals; Arginine Vasopressin; Atrial Natriuretic Factor; Body Weight; Catecholamines; Creatinine; Growth Hormone; Heart Rate; Hormones; Humans; Hydrocortisone; Macaca mulatta; Male; Peptide Fragments; Renin; Restraint, Physical; Social Isolation; Sodium; Stress, Psychological; Time Factors; Urea; Vasopressins

10 patients with renovascular hypertension (HRV) and 12 healthy persons were examined under water immersion (WI) conditions without and after blockade of opioid receptors with 2 mg of naloxone. Blood pressure, body mass, change of plasma volume, plasma molality, PRA, and serum values of AVP, aldosterone and catecholamines were evaluated. There were no significant changes between the two examined groups before and after WI. It seems that the drop in blood pressure induced by WI is not only the result of diminished activation of RAAS. The role of opioid receptors in controlling blood pressure and other evaluated parameters is likely in both examined groups.

Topics: Adult; Aldosterone; Body Height; Body Weight; Case-Control Studies; Catecholamines; Female; Humans; Hypertension, Renovascular; Immersion; Male; Naloxone; Narcotic Antagonists; Osmolar Concentration; Plasma Volume; Renin-Angiotensin System; Vasopressins

To understand the secretion and synthesis of atrial natriuretic peptide we measured immunoreactive atrial natriuretic peptide from plasma, heart tissues and brain areas, and ANP mRNA was determined from heart auricles and ventricles of vasopressin-deficient Brattleboro rats (DI) and from desmopressin treated Brattleboro rats (DI+DDAVP). Long-Evans rats (LE) served as controls. DI+DDAVP rats were given for 3 days sc. injections of 0.5 micrograms 1-desamino-8-D-arginine vasopressin in 1 mL saline twice a day. The rats were housed in single metabolic cages and urinary output and water intake were measured daily. All the body and organ weight parameters were similar in the three groups when the rats were killed. No change was seen in the plasma ANP level between the groups. The right ventricle of DI+DDAVP rats had significantly (P < 0.05) higher concentration of ANP than LE rats (15.8 +/- 4.4 vs. 3.4 +/- 0.6 ng mg-1 tissue). The left ventricle of DI and DI+DDAVP had significantly (P < 0.05) lower amounts of ANP mRNA than LE rats (0.5 +/- 0.2 vs. 1.3 +/- 0.2 and 0.5 +/- 0.1 vs. 1.3 +/- 0.2 arbitrary units). In the hypothalamus, the ANP concentration was significantly (P < 0.05) lower both in DI and in DI+DDAVP rats than in LE rats (9.3 +/- 1.3 vs. 14.5 +/- 1.6 and 6.1 +/- 0.6 vs. 14.5 +/- 1.6 pg mg-1 tissue). To conclude, although the water intake and urinary output of DI rats were changed towards normal with desmopressin treatment, the heart ventricular and hypothalamic ANP did not parallel the change.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Atrial Natriuretic Factor; Body Weight; Brain; Deamino Arginine Vasopressin; Diabetes Insipidus; Drinking; Heart Atria; Heart Ventricles; Hypoglycemic Agents; Male; Myocardium; Organ Size; Rats; Rats, Brattleboro; RNA, Messenger; Urination; Vasopressins; Water-Electrolyte Balance

Hemorrhage induces a rapid redistribution of protein from extravascular spaces into the blood. We studied the effects of acute, nontraumatic hemorrhage on tracer-albumin clearances into individual tissues of rats to determine if reduced protein extravasation could account for intravascular protein gain. Three groups were studied: 1) HEM animals were anesthetized with pentobarbital sodium and bled to a mean arterial pressure of 50 mmHg for 90 min; 2) HEM-RS animals were treated identical to group 1 and then resuscitated with 5% bovine serum albumin (BSA) until baseline arterial pressures were regained; 3) SHAM animals served as time controls. Hemodynamic variables were measured periodically throughout hemorrhage and clearance periods, and plasma samples were collected prior to death for protein and hormone analysis. Plasma clearance of 131I-BSA into individual tissues was measured over the final 30 min of each protocol with a terminal injection of 125I-BSA used to correct for intravascular volume. Reduction of blood volume by 35% in HEM-treated animals resulted in a marked decrease in albumin transport relative to the SHAM group (p < or = .05) in the following tissues: skeletal muscle (-65%), skin (-49%), ileum (-75%), cecum (-66%), colon (-67%), heart (-67%), and lung (-71%). Significant changes were not observed in the remaining tissues sampled: pancreas, kidney, and cerebrum. Albumin clearances in the HEM-RS group were slightly but not significantly lower than SHAM animals except for skeletal muscle, where transport remained depressed following resuscitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Acute Disease; Animals; Atrial Natriuretic Factor; Biological Transport; Blood Glucose; Blood Volume; Body Water; Body Weight; Brain; Colon; Coronary Vessels; Disease Models, Animal; Extravascular Lung Water; Hematocrit; Hemodynamics; Hemorrhage; Ileum; Lung; Male; Osmolar Concentration; Plasma Volume; Rats; Rats, Wistar; Resuscitation; Serum Albumin; Skin; Tissue Distribution; Vasopressins

The effect of prednisolone, given as a 4-day oral treatment, on 24-h ambulatory blood pressure rhythm, vasoactive hormones and correlation between blood pressure and vasoactive hormones were studied in 11 healthy men. Blood pressure was monitored at intervals of 15 min during the day and of 30 min during the night. Plasma concentrations of angiotensin II, aldosterone, atrial natriuretic peptide (ANP) and arginine vasopressin and serum concentration of insulin were measured in the morning during basal conditions. The 24-h systolic, diastolic and mean blood pressures were significantly higher after prednisolone treatment. Waking blood pressure was not significantly changed, but sleeping systolic and mean blood pressures were significantly elevated after treatment. The nocturnal systolic blood pressure fall was less pronounced after treatment (before 22%, and after 16%, p<0.01), whereas the nocturnal, mean and diastolic dips were preserved. ANP was significantly increased by prednisolone treatment, from 10.1 to 14.6 pmol l-1, p<0.005. The changes in concentration of ANP were significantly correlated to the changes in 24-h diastolic blood pressure (r = -0.63, p<0.05), 24-h mean blood pressure (r = -0.68, p<0.05), waking diastolic blood pressure (r = 0.83, p<0.01) and waking mean blood pressure (r = -0.67, p<0.01). We found that short-term prednisolone treatment elevated the overall 24-h blood pressure, reduced systolic blood pressure fall during sleep, and increased plasma concentration of ANP, and that the increase in ANP was inversely correlated to the increase in blood pressure. We suggest that the increase in ANP is a secondary and compensatory phenomenon which at least to some extent counteracts the hypertensive and sodium retaining effect of prednisolone.

Topics: Adult; Aldosterone; Angiotensin II; Atrial Natriuretic Factor; Blood Glucose; Blood Pressure; Body Weight; Circadian Rhythm; Heart Rate; Humans; Insulin; Male; Middle Aged; Potassium; Prednisolone; Sodium; Vasopressins

Insulin-like growth factor I (IGF-I) and IGF binding protein 1 (IGFBP-1) mRNAs are colocalized in the medullary thick ascending limb (MTAL) of the rat nephron, a segment that undergoes selective growth in response to elevated dietary protein. In the present study, rats were fed isocaloric diets containing variable protein content (6-40%) for 1-7 days, and changes in fractional renal weight, MTAL length, and regional DNA synthesis were assayed and compared with local changes in IGF-I/IGFBP-1 mRNAs, as determined by quantitative in situ hybridization. Rats switched to high-protein diets demonstrated increased IGF-I and decreased IGFBP-1 mRNA levels in MTALs, whereas those switched to low protein showed inverse changes. The increase in renal IGF-I mRNA was maximal at 2 days and was closely paralleled by significant increases in fractional renal weight, DNA synthesis, and MTAL length. Similar changes were seen in vasopressin-deficient Brattleboro and growth hormone (GH)-deficient dwarf rats in response to high-protein diets, suggesting that the effects of dietary protein in this model are not mediated by vasopressin or GH. The close spatial and temporal correlation between changes in renal IGF-I expression and changes in regional growth parameters strongly supports a role for locally produced IGF-I in the induction of protein-induced renal growth.

Topics: Animals; Body Weight; Carrier Proteins; Dietary Proteins; Gene Expression; Growth Hormone; Hyperplasia; Insulin-Like Growth Factor Binding Protein 1; Insulin-Like Growth Factor I; Kidney; Organ Size; Rats; Rats, Brattleboro; Rats, Mutant Strains; Rats, Sprague-Dawley; RNA, Messenger; Somatomedins; Vasopressins

The performance of a passive avoidance task (measured for two trials based upon number of complete step-downs and latency to respond) and blood glucose levels were examined in five groups of animals. The groups included vasopressin-deficient (DI) and vasopressin-containing (LE) rats under ad lib (AL) and food-restricted (FR) conditions, as well as DI-FR animals provided with access to an 8% sucrose solution (SUC). In the AL condition, no significant differences were found between DI and LE animals in either step-down occurrences or blood glucose levels. However, the DI animals were significantly slower in latency to respond in trial 1. With FR, the LE animals resembled the LE-AL animals in both passive avoidance behavior and blood glucose levels. The DI-FR animals that were not provided with SUC showed an impairment in passive avoidance behavior and low blood glucose levels, whereas DI-FR animals provided with SUC showed an amelioration of passive avoidance deficiencies and had blood glucose levels comparable to AL animals and LE-FR animals. On trial 2, a significant negative correlation was found between number of step-down occurrences and blood glucose levels, and a significant positive correlation was found between latency to respond and blood glucose levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Analysis of Variance; Animals; Avoidance Learning; Blood Glucose; Body Weight; Drinking Behavior; Feeding Behavior; Food Deprivation; Male; Rats; Reaction Time; Reference Values; Sucrose; Vasopressins

Xeric-adaptation was studied during 28 days of total water deprivation (TWD) in Notomys alexis. Beyond 7 days, the initial reductions in body weight and increases in haematocrit, plasma renin and juxtaglomerular (JG) cell morphological activity returned to normal. Mus musculus showed similar changes at 7 days but could not be maintained thereafter. TWD decreased the blood pressure of Notomys but endogenous angiotensin and vasopressin did not support pressure to a greater extent than controls, as revealed by selective antagonists. The normal morphology of the JG apparatus in Notomys was similar to other rodents. Fluid volume and blood pressure maintenance during TWD in Notomys do not depend upon enhanced activities of the renin-angiotensin and antidiuretic hormonal systems.

Topics: Adaptation, Physiological; Animals; Arginine Vasopressin; Blood Pressure; Body Weight; Enalaprilat; Hematocrit; Juxtaglomerular Apparatus; Male; Mice; Mice, Inbred BALB C; Renin; Rodentia; Saralasin; Vasopressins; Water Deprivation

The present study was undertaken to determine whether a non-peptide arginine vasopressin (AVP) antagonist [5-dimethylamino-1-(4-(2-methylbenzoylamino)benzoyl]-2,3,4,5-tetra hydro-1H- benzazepine] (OPC-31260) improves the impaired water excretion in rats with experimental liver cirrhosis. Male Wistar rats weighing 200 to 250 g were injected in an equal volume (4 ml/kg) of carbon tetrachloride and olive oil at an interval of seven days for three months, causing liver cirrhosis with ascites. Control rats were injected with only olive oil. Body weight (body wt) and hematocrit (Hct) were lower in the cirrhotic rats than the control rats (body wt 360.7 vs. 238.5 g, P < 0.01; Hct 46.3 vs. 39.2%, P < 0.01). A water loading test (30 ml/kg) was carried out and 20-minute urine collections were made for three hours. The percent of water load excreted was 62.5% in the cirrhotic rats, a value significantly less than that of 102.1% in the control rats. However, its percent increased to 215.1% after the oral administration of 5 mg/kg OPC-31260 (P < 0.01). Minimal urinary osmolality (UOsm) was 185.5 mOsm/kg H2O in the cirrhotic rats receiving the vehicle, a value greater than the control rats of 125.5 mOsm/kg H2O (P < 0.01). The oral administration of 5 mg/kg OPC-31260 reduced minimal UOsm to 85.2 mOsm/kg H2O in the cirrhotic rats (P < 0.01). Urinary excretion of sodium was lower in the cirrhotic rats than the control rats (87.1 vs. 312.4 microEq/3 hr, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Arginine Vasopressin; Benzazepines; Blood Pressure; Body Weight; Diuresis; Glomerular Filtration Rate; Liver Cirrhosis, Experimental; Male; Osmolar Concentration; Rats; Rats, Wistar; Vasopressins; Water-Electrolyte Balance

Alpha-fluoromethylhistidine (FMH), a histamine synthesis inhibitor, was infused into the lateral cerebral ventricle of male Long-Evans rats for 7 days at a dose of 60 mcg/day. During this period animals were housed in metabolic cages; water and food consumption were measured and urine samples were collected. FMH-treated rats ate significantly more than controls and had a significantly greater weight increase. Concomitantly, sodium and potassium excretion increased. On the seventh day, rats were injected i.p. with 6.67 ml/kg of either 5.8% NaCl or physiological saline. Animals were decapitated 1 h after injection and plasma vasopressin, corticosterone and posterior pituitary vasopressin levels were determined by radioimmunoassay. NaCl loading significantly increased plasma vasopressin in control rats but not in rats pretreated with FMH. FMH alone had no effect. There were no significant changes in pituitary vasopressin or plasma corticosterone. These results clearly suggest an inhibitory role for the histaminergic system in the regulation of food intake. They also agree with, although not proving, the stimulatory control of vasopressin release by the histaminergic system in rat brain.

Topics: Animals; Body Fluids; Body Weight; Brain; Corticosterone; Dose-Response Relationship, Drug; Drinking; Eating; Histamine; Injections, Intravenous; Male; Methylhistidines; Pituitary Gland, Posterior; Rats; Sodium Chloride; Vasopressins; Water

Neuroendocrine disturbances are among the significant problems associated with animal and human seizures. To investigate the mechanisms for these disturbances, we examined changes in the expression of vasopressin (VP) mRNA in the hypothalamic magnocellular neuroendocrine cells of rats after amygdala kindled seizures, a model for temporal lobe epilepsy. A prominent increase in VP mRNA was found in the supraoptic nucleus of kindled animals by one week after the last seizure which persisted for at least 4 months. The increase occurred bilaterally in the SON and remained unchanged despite the absence of further stimulation, seizures or change in body fluid homeostasis. Since the VP mRNA change after kindling correlated with the duration of afterdischarge but not the number of amygdala stimuli the change appears to be an effect of the seizure. This chronic increase in VP mRNA appears to reflect a change in neuroendocrine gene expression and may identify an important new mechanism of plasticity that contributes to the neuroendocrine disturbances accompanying epilepsy.

Topics: Amygdala; Animals; Body Weight; Electric Stimulation; Electroencephalography; Gene Expression; In Situ Hybridization; Kindling, Neurologic; Male; Rats; Rats, Sprague-Dawley; RNA, Messenger; Seizures; Vasopressins

In an earlier study, we reported that chronic intravenous administration of the V1 agonist [Phe2,Ile3,Orn8]vasopressin (V1AG) results in sustained hypertension. The present study was designed to determine whether V1-induced hypertension may be related specifically to intrarenal actions of this peptide. Chronic infusion of the V1 agonist into the medullary interstitial space of a single remaining kidney of normal, conscious Sprague-Dawley rats at the rate of 2 ng.kg-1.min-1 for 14 days resulted in a sustained rise of 18 mmHg of mean arterial pressure (MAP). After withdrawal of V1AG, MAP returned to the baseline level. During the first day of V1AG infusion, there was a net loss of body sodium and no evidence of fluid retention throughout the period of hypertension. Plasma osmolality, sodium and potassium concentration, and water intake and body weight were not significantly affected by medullary interstitial infusion of V1AG. Renal medullary interstitial infusion of an equimolar amount of arginine vasopressin (AVP) did not affect MAP. Chronic medullary interstitial infusion of the selective V1 antagonist d(CH2)5[Tyr(Me)2,Ala-NH(2)9]AVP in equimolar amounts (2.5 ng.kg-1.min-1) prevented the MAP increase elicited by intravenous V1AG. However, intravenous administration of the V1 antagonist at the same rate together with V1AG (n = 7) failed to prevent hypertension. The results indicate that hypertension can be elicited by chronic stimulation of renal medullary V1 vasopressin receptors. They also suggest that some V2 agonistic properties of AVP may restrict the hypertensive action of this hormone. The mechanism for the rise of arterial pressure remains to be determined.

Topics: Animals; Arginine Vasopressin; Blood Pressure; Body Weight; Diuresis; Drug Administration Schedule; Heart Rate; Hypertension; Infusions, Parenteral; Kidney Medulla; Male; Ornipressin; Rats; Rats, Sprague-Dawley; Receptors, Vasopressin; Time Factors; Vasopressins

The mechanisms whereby the continuous administration of initially subpressor doses of angiotensin II (ANG II) leads to pressor hyperresponsiveness and gradual development of hypertension were investigated. Male Sprague-Dawley rats (350 to 400 g) were given ANG II intraperitoneally, 200 ng/kg/min, for 24 h, 7 to 10 days, or 6 weeks. Vehicle-infused rats were controls. Pressor responses to incremental doses of ANG II, norepinephrine (NE), and serotonin were measured in chloralose-anesthetized rats, before and after neurohumoral blockade, and the main findings were confirmed in awake, free-moving rats with implanted catheters. Pressure responses to ANG II and NE were also measured in the isolated, pump-perfused mesenteric circulation of rats after 7 to 10 days of ANG II or sham infusion. Compared with control rats, there were no hemodynamic changes in ANG II-treated rats at 24 h. After 7 to 10 days of ANG II treatment, tail systolic blood pressure rose by 13 mm Hg (P < .01) and pressor responses to ANG II (P < .01) but not to NE or serotonin were increased. Pressor hyperresponsiveness was due in part to potentiation of vascular responses because pressure responses to ANG II (P < .002) but not to NE were also increased in the mesenteric circulation of ANG II-treated rats. By 6 weeks, mild hypertension was well established in ANG II-treated rats and pressor responses were increased to both ANG II (P < .05) and NE (P < .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Amino Acid Sequence; Anesthesia; Angiotensin II; Animals; Blood Pressure; Body Weight; Chloralose; Heart Rate; Hypertension; Injections, Intraperitoneal; Male; Molecular Sequence Data; Norepinephrine; Rats; Rats, Sprague-Dawley; Renin; Serotonin; Splanchnic Circulation; Vasopressins

The lasting effects of a 9-day neonatal exposure to vasopressin and oxytocin were examined in the rat to discover if peptide administration results in organizational effects. When tested in young adulthood, brain growth, not body growth, appeared to be impaired. Basal and challenge tests of urine production, carried out to see the development of the hormonal antidiuretic function of vasopressin, revealed no lasting changes, and therefore did not confirm earlier findings of an induced mild polyurea. Behavioral testing of learning by making use of a one-trail step-through paradigm with a 24-h retention trial--a test that is sensitive to vasopressin--did not show impairments. Open field tests, however, showed enhanced emotionality in the vasopressin-treated females, as well as an initially increased ambulation in the males, and increased grooming in both sexes, the latter also having been reported to be induced by vasopressin administration in the septal areas. Oxytocin treatment did not produce lasting changes. Our conclusion, therefore, is that peripherally circulating vasopressin can affect the organizational development of the rat brain. It remains to be established whether this is an effect obtained through changes in the general peripheral physiology or a reflection of plasticity phenomena at the level of central vasopressin neurotransmission.

Topics: Animals; Animals, Newborn; Behavior, Animal; Body Weight; Brain; Eye; Female; Learning; Male; Oxytocin; Rats; Rats, Wistar; Retention, Psychology; Sex Characteristics; Urine; Vasopressins

The effect of dextroamphetamine sulfate (Dexedrine) on plasma opioid peptides, hormones, and other metabolites was studied in eight female subjects with idiopathic (orthostatic) edema and five healthy females. All subjects were given 20 mg of dextroamphetamine sulfate, a drug widely used in the treatment of this disorder, and blood samples were collected before and 30, 60, and 90 minutes after treatment. Patients with idiopathic (orthostatic) edema had significantly lower plasma sodium levels but higher blood urea nitrogen, aldosterone, and renin levels. D-amphetamine decreased aldosterone and renin levels in both groups. Plasma adrenocorticotropin levels were lower whereas met-enkephalin levels were higher in idiopathic (orthostatic) edema subjects compared to control subjects. D-amphetamine had no significant effect on plasma beta-endorphin, adrenocorticotrophic hormone, or enkephalins. Our data indicate that opioid peptides, especially enkephalins, and adrenocorticotrophic hormone may be involved in the pathogenesis of idiopathic (orthostatic) edema syndrome, but they seem uninvolved in the aldosterone- and renin-lowering action of amphetamine. It is possible that amphetamine is acting further down the chain, either directly on the adrenal and kidney or the microvasculature, rather than at hypothalamus-pituitary axis.

Topics: Adrenocorticotropic Hormone; Adult; Aldosterone; beta-Endorphin; Blood Urea Nitrogen; Body Weight; Dextroamphetamine; Dopamine; Edema; Endorphins; Enkephalin, Leucine; Enkephalin, Methionine; Female; Humans; Hypotension, Orthostatic; Middle Aged; Renin; Sodium; Spironolactone; Syndrome; Vasopressins

Despite the well-recognized vasoconstrictor and fluid-retaining actions of vasopressin, prolonged administration of arginine vasopressin (AVP) to normal animals or humans fails to produce sustained hypertension. The present study was performed to elucidate the role of the V1 receptor in determining the ability of AVP to produce sustained hypertension. Conscious Sprague-Dawley rats with implanted catheters were infused with the selective V1 agonist, [Phe2,Ile3,Orn8]vasopressin (2 ng.kg-1.min-1), for 14 days in amounts that were acutely nonpressor. Blood pressure (MAP), heart rate (HR), body weight, and water intake (WI) were determined daily. Plasma AVP, plasma catecholamines norepinephrine and epinephrine, plasma osmolality, and electrolyte concentration were determined before and on days 1 and 7 of infusion. MAP increased significantly by 10.4 +/- 4.5 mmHg on day 1 and rose to 22 +/- 5 mmHg above control by day 14 (transient decrease on days 6-9) and then fell to control levels after the infusion was stopped. HR did not change significantly. Plasma AVP immunoreactivity increased from 2.5 +/- 0.3 to 10.9 +/- 2.1 pg/ml, whereas norepinephrine tended to fall only on day 1, with epinephrine only slightly elevated on day 7. No evidence of fluid retention was found, and rats lost sodium only on the first day of V1 agonist infusion. Body weight increased throughout the study but was unrelated to the changes of MAP. We conclude that chronic stimulation of V1 receptors results in sustained hypertension in rats.

Topics: Animals; Arginine Vasopressin; Blood Pressure; Body Weight; Diuresis; Heart Rate; Hormones; Hypertension; Injections, Intravenous; Male; Natriuresis; Ornipressin; Rats; Rats, Sprague-Dawley; Time Factors; Vasopressins

Prolonged use of glucocorticoids (GCs) can cause prolonged suppression of the hypothalamus-pituitary-adrenal (HPA) axis. This study examined the possibility that corticotropin or its secretagogues such as vasopressin, corticotropin-releasing hormone (CRH), or insulin accelerate recovery of the HPA axis after prolonged treatment with dexamethasone (DEX). Suppression of the HPA axis was induced in rats by DEX at a dosage of 250 micrograms/100 g body weight (BW)/d for 14 days, after which rats were administered saline, corticotropin (Cortrosyn 0.1 mg), ovine CRH (oCRH 6 micrograms), vasopressin (2 U), or insulin (2 U) each morning. Adrenal weight (AW), BW, plasma corticosterone, and corticotropin, as well as pituitary corticotropin content, decreased significantly after DEX treatment. The plasma corticotropin level was significantly elevated 7 days after discontinuation of DEX treatment (day 8) and remained so until day 11, whereas the pituitary corticotropin content had returned to normal on day 8. Plasma corticosterone was suppressed until day 8, but was not significantly different from normal on day 11. The AW was also decreased until day 4, but was not different from normal on day 8 or day 11. The BW of experimental rats remained subnormal during the study period. Treatment of DEX-suppressed rats with exogenous corticotropin induced adrenal hyperplasia, but suppressed the plasma corticotropin level and delayed the normalization of plasma corticosterone until day 11. The insulin-treated group differed in no respect from the saline-treated group. Treatment with oCRH or vasopressin for 8 days normalized plasma and pituitary corticotropin, as well as plasma corticosterone. Hypothalamic immunoreactive CRH (iCRH) did not differ among any treatment groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adrenal Glands; Animals; Body Weight; Corticosterone; Corticotropin-Releasing Hormone; Dexamethasone; Hypothalamo-Hypophyseal System; Hypothalamus; Insulin; Male; Organ Size; Pituitary Gland; Pituitary-Adrenal System; Rats; Rats, Wistar; Vasopressins

Tail-suspension of rats has been employed for the study of disuse atrophy of hindlimb muscles and bones. From our study, it is suggested that stress exacerbates muscle and bone atrophy; however, the determination of stress hormones has been inappropriately performed. For assessing the effect of tail suspension on stress hormone secretion, suspension was performed for 7 days in a metabolic cage. Urinary excretions of corticosterone, catecholamines and antidiuretic hormone were determined during the 7-day suspension. Urine volume was unchanged during the suspension period, whereas water consumption was decreased during suspension. Urinary excretion of corticosterone and catecholamines increased significantly during the initial 3 days of suspension. The excretion of antidiuretic hormone increased throughout the suspension period. Our results demonstrated that the determination of urinary excretion of these hormones is useful for evaluating the stress reaction.

Topics: Adrenal Glands; Animals; Body Weight; Corticosterone; Epinephrine; Hindlimb Suspension; Male; Muscular Atrophy; Norepinephrine; Organ Size; Rats; Rats, Wistar; Stress, Physiological; Thymus Gland; Urine; Vasopressins

Anorexia nervosa is associated with vasopressin, oxytocin and serotonin abnormalities. Because of the relationship between exercise and anorexia nervosa, we explored the weight-loss syndrome produced by wheel running in food-deprived rats. Its effects on regional vasopressin and oxytocin concentrations were determined under basal conditions and following systemic fluoxetine. Weight-matched, exercised and unexercised rats served as controls. Fluoxetine caused abnormalities in suprachiasmatic vasopressin and dynorphin A content and in thymus oxytocin content that did not occur in weight-matched or exercised controls. No syndrome-specific anomalies occurred in the hypothalamo-neurohypophysial system or dorsal vagal complex (DVC). However, weight reduction and fluoxetine increased circulating vasopressin; moderate exercise caused fluoxetine-induced elevations in posterior pituitary vasopressin and oxytocin; and, unlike the other groups, fluoxetine increased DVC oxytocin in freely fed unexercised rats. It was concluded that syndrome-specific vasopressin and oxytocin abnormalities occur that are not secondary to weight loss or moderate exercise; that weight loss or fluoxetine increases circulating vasopressin; that moderate exercise alters neurohypophysial vasopressin and oxytocin content; and that weight loss or exercise inhibits a fluoxetine-stimulated increase in DVC oxytocin. Finally, it was argued that the fluoxetine abnormalities indicate possible serotonin dysfunction in the syndrome.

Topics: Animals; Anorexia Nervosa; Behavior, Animal; Body Weight; Dynorphins; Eating; Fluoxetine; Male; Oxytocin; Physical Conditioning, Animal; Rats; Rats, Sprague-Dawley; Suprachiasmatic Nucleus; Supraoptic Nucleus; Vagus Nerve; Vasopressins

Topics: Animals; Body Weight; Lung; Male; Obesity; Organ Size; Physical Exertion; Radioimmunoassay; Rats; Rats, Sprague-Dawley; Rats, Zucker; Vasopressins

1. The present study was undertaken to test whether insulin acts as a pressor agent and causes hypertension in rats. 2. Insulin at doses of 10 or 100 units day-1 kg-1 was administered daily by subcutaneous injection to normal rats for 6 weeks. As it has been suggested that sodium retention plays a major role in the putative hypertensive activity of this hormone, insulin was also administered to saline- (1% NaCl) drinking rats according to the same protocol. Water- and saline-drinking rats served as controls. 3. After 6 weeks of insulin treatment, the mean arterial blood pressure did not increase in any of the insulin-treated or the insulin-salt-treated groups. However, in both insulin-salt-treated groups, absolute and relative ventricular and renal hypertrophy with increased ventricular water content as well as increased urine output with reduced osmolality were observed. 4. All insulin-treated groups showed increased plasma levels of glucose, insulin and antidiuretic hormone when compared with their respective controls. 5. These results demonstrate that chronic insulin treatment did not increase blood pressure in rats, even when drinking water was supplemented with NaCl, and suggest that a polyuria-polydipsia syndrome was present in both insulin-salt-treated groups. Moreover, increased plasma levels of antidiuretic hormone were observed in all insulin-treated groups.

Topics: Animals; Blood Glucose; Body Weight; Electrolytes; Hypertension; Insulin; Kidney; Male; Organ Size; Rats; Rats, Wistar; Sodium Chloride; Vasopressins

The neurons of the supraoptic nucleus in the rat hypothalamus are reported not to possess receptors for gonadal steroids and sexual dimorphism has not previously been described in this nucleus. We have analysed this nucleus in groups of Sprague-Dawley rats (six males or six females per group), one, two, six, 12 and 18 months after birth. Body and brain weights were recorded, the volume of the nucleus was determined from the right hemisphere and all other quantitative parameters were determined from the left nucleus. In addition, different groups of four male and four female rats aged two and 18 months were analysed after immunocytochemical staining to distinguish between vasopressin and oxytocin neurons. The total number of neurons was constant in all groups studied, despite which the volume of the supraoptic nucleus increased progressively with age in both males and females. The cross-sectional areas and volumes of supraoptic neurons also increased with age. The volume density of the neuropil remained constant in all groups and there was a progressive decrease with age in the numerical density of neurons. Immunocytochemistry revealed that the age-dependent increases in the size of the neurons involved primarily the vasopressin neurons. The age-related changes were much greater in males than in females, resulting in significant differences between the sexes at two, six, 12 and 18 months with respect to the volume of the supraoptic nucleus, the cross-sectional areas of neuronal somata and nuclei, and the volume of supraoptic neurons. Thus the supraoptic nucleus and its vasopressin neurons are larger in adult males than in age-matched females. Since we have also shown that body weight is very closely correlated with changes in the size of supraoptic neurons, and adult male rats are heavier than females of the same age, we suggest that these size changes reflect adaptation of the vasopressin neurons of the supraoptic nucleus to increasing functional demands associated with the regulation of water balance in bodies of increasing size.

Topics: Aging; Analysis of Variance; Animals; Body Weight; Female; Immunohistochemistry; Male; Neurons; Organ Size; Oxytocin; Rats; Rats, Sprague-Dawley; Sex Characteristics; Supraoptic Nucleus; Vasopressins

To determine whether thirst mechanisms are altered in nondiabetic patients with chronic renal failure on hemodialysis, 4 patients with an average weight gain between dialysis sessions of more than 5% of dry body weight (group I), 5 patients with less than 3% weight gain (group II), and a group of 6 healthy subjects (group III) were submitted to infusion of hypertonic saline. After infusion the subjects had free access to water. Thirst was evaluated by visual analogue rating scales. Despite similar increments of effective plasma osmolality during saline infusion, patients of group I were thirstier than groups II and III (p less than 0.005 and p less than 0.01, respectively). Changes in thirst ratings were similar in groups II and III. Osmotic thresholds for thirst onset were similar in groups II and III (288.9 +/- 8.5 and 289.8 +/- 3.4 mosm/kg, respectively), but lower in group I (277.6 +/- 7.6 mosm/kg). Nevertheless, great variations were observed in the latter group. Thus, 2 patients showed thresholds for thirst within the normal range, whereas the others had low osmolar thresholds for thirst and baseline plasma osmolalities and high basal thirst scores. During the drinking period, the patients of group I drank more (14.2 +/- 2.8 ml/kg) than those of groups II (5.3 +/- 1.6 ml/kg; p less than 0.02) and III (10.2 +/- 1.6 ml/kg; n.s.) The plasma levels of angiotensin II in uremic patients were higher than in healthy subjects, although there were no differences between groups I and II and no correlation between basal angiotensin II levels and the interdialytic weight gain.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aged; Angiotensin II; Body Weight; Female; Humans; Kidney Failure, Chronic; Male; Middle Aged; Osmolar Concentration; Renal Dialysis; Saline Solution, Hypertonic; Thirst; Vasopressins; Water-Electrolyte Balance

Effects of dehydration on vasopressin-secreting cells (VP cells) of the supraoptic nucleus (SON) and the paraventricular nucleus (PVN) in the Mongolian gerbils were studied immunocytochemically and morphometrically. The plasma osmolality was measured at the time of sacrifice of individual animals and the body weight was measured every day during dehydration. The plasma osmolality increased significantly on day 3 of dehydration, followed by a gradual increase to reach nearly its equibilium state on day 10. The body weight decreased rapidly until day 10, followed by a gradual decrease thereafter. The area of VP cells increased significantly in both the SON and PVN on day 1 of dehydration, the level being nearly the same until days 3 to 5 and going up on day 7 to reach the plateau after day 15. These findings seem to reflect a compensation mechanism between the volume of body fluid and the plasma osmolality and to reflect responses of VP cells to the osmotic stimuli. Electron microscopic observation revealed that, at the beginning and late stages of dehydration, the increase in the area of VP cells was in parallel with the expansion of the Golgi area and with the distension of cisternae of the rough endoplasmic reticulum.

Topics: Animals; Body Weight; Dehydration; Gerbillinae; Immunohistochemistry; Male; Microscopy, Electron; Osmolar Concentration; Paraventricular Hypothalamic Nucleus; Rodent Diseases; Supraoptic Nucleus; Vasopressins

The renal effects of acyclovir (100 mg/kg body weight i.p. for 7 days) were studied in rats. All animals became polyuric and presented an increase in blood urea nitrogen and fractional excretion of sodium and potassium. During hypotonic saline infusion, the acyclovir-treated rats showed higher distal fractional delivery compared to normal rats (27.8 +/- 4.7 vs. 11.3 +/- 0.9%, p less than 0.01) and a lower ratio of free-water clearance to distal sodium delivery (33.5 +/- 7.8 vs. 57.2 +/- 3.9%, p less than 0.02). Following hypertonic saline infusion, the ratio of osmolar to inulin clearance was higher in acyclovir rats (47.8 +/- 7.4%) than in normal rats (27.0 +/- 4.8%), whereas the ratio of free-water reabsorption to osmolar clearance was lower in the acyclovir rats (13.6 +/- 4.6 vs. 38.2 +/- 3.2%, p less than 0.01). These findings suggest an effect of acyclovir on the proximal tubule, thick ascending limb and/or inner medullary collecting duct (IMCD). In vitro measurements of 3H2O permeability of perfused IMCD of normal rats showed that vasopressin (50 microU/ml) added to the bath increased the diffusional water permeability (43.4 +/- 4.8 vs. 105.6 +/- 9.1 x 10(-5) cm/s), while in acyclovir rats, the control value (58.8 +/- 9.1 x 10(-5) cm/s) did not increase significantly in the presence of vasopressin (71.3 +/- 13.6 x 10(-5) cm/s). These results suggest that high doses of acyclovir produce azotemia and an abnormal function of the proximal tubule and thick ascending limb associated with resistance to vasopressin of the IMCD.

Topics: Acyclovir; Animals; Blood Urea Nitrogen; Body Weight; Dose-Response Relationship, Drug; Kidney; Male; Perfusion; Potassium; Rats; Rats, Wistar; Sodium; Vasopressins

Our previous study revealed major ion transport alterations that resulted in a pronounced elevation of red cell Na+ content in DOCA-salt treated homozygous vasopressin-deficient (DI) Brattleboro rats in which only a moderate increase of systolic blood pressure occurred. In contrast, no changes of red cell Na+ content were observed in heterozygous vasopressin-secreting (non-DI) Brattleboro rats with a severe DOCA-salt hypertension. Using a chronic supplementation of DI rats with an antidiuretic agonist dDAVP (1-desamino-8-D-arginine vasopressin) we did not demonstrate any significant changes of red cell ion transport in dDAVP-treated DI rats with a fully developed DOCA-salt hypertension. The absence of ion transport alterations seems to be mainly due to dDAVP-induced correction of altered K+ metabolism seen in DOCA-salt treated DI animals. It can be concluded that DOCA-salt hypertension can develop even without red cell ion transport alterations which are usually caused by cell K+ depletion.

Topics: Animals; Blood Pressure; Body Weight; Deamino Arginine Vasopressin; Desoxycorticosterone; Erythrocytes; Female; Hypertension, Renovascular; Ion Transport; Osmolar Concentration; Potassium; Rats; Rats, Brattleboro; Sodium; Vasopressins

1. The mechanism of the antihypertensive effects of n-3 fatty acids were examined in spontaneously hypertensive rats (SHR) by feeding 'Max EPA' fish oil or hydrogenated coconut oil and determining the responses of perfused mesenteric resistance vessels to various contractile agents and peri-arterial nerve stimulation. 2. Fish oil feeding for 4 weeks caused a decrease in the responses to exogenous noradrenaline and electrical nerve stimulations but had no significant effect on vasopressin and KCl (80 mmol/L) induced contractions. 3. These results provide direct evidence for specific attenuation of vascular responses to sympatho-adrenal stimulation in resistance vessels following fish oil feeding and may account for the antihypertensive effects seen in humans and in some forms of hypertension in rats.

Topics: Animals; Body Weight; Dietary Fats, Unsaturated; Electric Stimulation; Fish Oils; Hypertension; Male; Mesenteric Arteries; Muscle Contraction; Muscle, Smooth, Vascular; Norepinephrine; Perfusion; Rats; Rats, Inbred SHR; Vascular Resistance; Vasopressins

To observe the mechanism of alcoholic testicular damage, in a previous experiment we used weanling male SD rats aged 45 days, weighing about 200 g, and fed a liquid diet (Lieber's) containing 5% ethanol. The latter accounted for 36% of total caloric intake for 7 weeks, but did not result in testicular atrophy. In a later experiment, we used a liquid diet in which ethanol accounted for 46% of the total calorie count. It provided a high-fat, low-protein content which simulated the nutritional background of patients with alcoholic liver diseases. This diet resulted in testicular atrophy. Histological and biochemical changes accompanying this experimental testicular atrophy included the following: 1) The testes of alcohol-fed animals contained smaller seminiferous tubules with reduced numbers of total cells, but no degeneration was seen in the spermatids. 2) In the peritubular wall of the seminiferous tubules, we observed curvature, irregularities, infolding of the basement membrane, and lamellation of the lamina densa, as well as hyperplasia of collagen fibers in the tunica propria. 3) In the cytoplasm of the Sertoli cells, deposits of gigantic fat droplets and stratification of the mitochondria were observed. The permeability of the Sertoli cell tight junction was confirmed using the Lanthanum method. 4) Testosterone levels in both the serum and testes declined. 5) Lactate dehydrogenase-X (LDH-X) activity in the testes declined. 6) Low Km alcohol dehydrogenase (ADH) activity localized in the testicular interstitial tissue was increased. These results indicate that the composition of three major nutritional elements as well as alcohol concentration are important in the mechanism of alcoholic testicular damage, and this damage affects both the testicular interstitial cell and the seminiferous tubules, particularly the Sertoli cells and peritubular wall of the latter. In addition, the findings suggest that ADH is involved in alcohol metabolism in the interstitial cells of the testes.

Topics: Alcoholism; Animals; Body Weight; Ethanol; Male; Rats; Rats, Inbred Strains; Seminiferous Tubules; Spermatogenesis; Testicular Diseases; Testis; Vasopressins

Topics: Bed Rest; Body Weight; Calcium; Drinking; Female; Humans; Urodynamics; Vasopressins

To determine whether the paraventricular nucleus (PVN) contributes to the development of hypertension in spontaneously hypertensive rats (SHR), we compared cardiovascular responses to ganglionic blockade with hexamethonium or vasopressin antagonism with dPVAVP in sham-operated or PVN lesioned SHR and Wistar-Kyoto rats (WKY). Lesions were produced electrolytically when the rats were 5 weeks old. During the next 3 weeks, tail-cuff measurements showed that the development of hypertension in SHR was inhibited, while systolic pressure in WKY was unaffected. Mean pressures recorded directly from the femoral artery at 8 weeks of age were lower in lesioned than in sham-operated SHR (141 +/- 5 vs 110 +/- 3 mm Hg, P less than 0.05), but did not differ in corresponding WKY groups (110 +/- 4 vs 112 +/- 5 mm Hg). Depressor responses to ganglionic blockade induced by i.v. injection of hexamethonium (25 mg/kg) were significantly larger in sham-operated than in lesioned SHR (-41 +/- 4% vs -28 +/- 3%, P less than 0.05). By contrast, vasopressin antagonism with dPVAVP did not alter blood pressure in all rat groups. In 24-h urine samples, excretion of vasopressin was unaffected, but that of norepinephrine was significantly reduced in lesioned SHR. These findings suggest that the PVN contributes to the development of spontaneous hypertension by sympathetic activation without increasing vasopressin secretion.

Topics: Animals; Blood Pressure; Body Weight; Catecholamines; Deamino Arginine Vasopressin; Drinking; Ganglionic Blockers; Heart Rate; Hexamethonium Compounds; Hypertension; Male; Paraventricular Hypothalamic Nucleus; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Sympathetic Nervous System; Vasopressins

The influence of mild dehydration on plasma levels of atrial natriuretic peptide (ANP) was studied in both young (aged 18 to 25 years) and elderly (aged 72 to 86 years) subjects. We expected that dehydration would lower ANP concentrations due to the ensuing volume contraction. A different response of the ANP hormonal system in the elderly might help to explain the observation that elderly subjects are more predisposed to dehydration as compared to young subjects. Dehydration was induced by restriction of fluid intake to 25% of normal for one day. During the study, urinary osmolality increased while osmolar clearance and body weight decreased. Basal ANP concentrations were higher in the elderly subjects. However, these levels did not change during the dehydration study neither in the young nor in the elderly subjects. This may be explained by the activation of counter-regulatory systems preventing a decrease in central blood volume and hence a decrease in ANP concentration.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Aging; Atrial Natriuretic Factor; Body Weight; Dehydration; Female; Humans; Male; Osmolar Concentration; Vasopressins

To study selected cardiovascular, thermoregulatory, and hormonal responses to the consumption of glycerol solutions during exercise, nine subjects cycled for 90 min at 50% peak O2 uptake in a 30 degree C, 45% relative humidity environment. Beverages tested included a 10% glycerol solution (G), a 6% carbohydrate-electrolyte beverage (CE), the 6% carbohydrate-electrolyte beverage plus 4% glycerol (CEG), and a water placebo (WP) ingested at regular intervals during the first 60 min of exercise. The beverages were administered in counterbalanced order with subjects serving as their own controls. Ingestion of the glycerol solutions resulted in an increase in plasma osmolality and attenuation of the decrease in plasma volume associated with the WP treatment (P less than 0.05). Plasma renin activity was highest with WP (P less than 0.05), and G was associated with increased antidiuretic hormone levels (P less than 0.05). Ratings of perceived thirst were lowest for CEG and G, and the frequency of gastrointestinal distress was greatest for G (P less than 0.05). However, no differences among beverage treatments were observed for heart rate, esophageal temperature, sweat rate, ratings of perceived exertion, or changes in cortisol and aldosterone levels. These data indicate that there are no substantial metabolic, hormonal, cardiovascular, or thermoregulatory advantages to the consumption of solutions containing 4 or 10% glycerol during exercise.

Topics: Adult; Aldosterone; Blood Glucose; Body Temperature Regulation; Body Weight; Esophagus; Exercise; Fatty Acids, Nonesterified; Female; Glycerol; Hemodynamics; Hormones; Humans; Male; Osmolar Concentration; Renin; Sweating; Vasopressins

Heat-stressed pregnant ewes deliver intrauterine growth-retarded lambs. Selected maternal and fetal changes were investigated during acute heat stress in order to elucidate the mechanism for this growth retardation. Uterine blood flow decreased 20 to 30% in pregnant ewes during 1 degree C increases in core temperature. The decreases were accompanied by 60 and 100% increases in serum oxytocin and antidiuretic hormone, respectively. These effects were mimicked by salt loading or injections of antidiuretic hormone or oxytocin, suggesting a role for either or both hormones in regulating uterine blood flow during pregnancy. Chronically heat-stressed pregnant ewes were delivered by Caesarean section. Their fetuses were approximately 20% smaller than thermoneutral controls. Within each pair of heat-stressed twins, one fetus weighted one-third less than its litter mate. No difference in weights were observed within the control twins. The livers and brains of the heat-stressed fetuses were disproportionate in size. The livers from the small heat-stressed twins contained only one-half the protein of the controls and one-fourth the protein of their litter mates. Muscle protein was decreased in the heat-stressed fetuses, and liver and muscle glycogen were elevated as were liver arginase, glutamate-pyruvate transaminase and muscle creatinine. These results are consistent with the following hypothesis: heat stress stimulates the release of maternal antidiuretic hormone or oxytocin, which reduces uterine blood flow and causes a shift in fetal metabolism from anabolic to catabolic pathways; one fetus of heat-stressed twins is more severely affected than its litter mate.

Topics: Animals; Body Weight; Female; Fetal Growth Retardation; Hot Temperature; Litter Size; Myocardium; Organ Size; Oxytocin; Pregnancy; Pregnancy Complications; Regional Blood Flow; Sheep; Sheep Diseases; Stress, Physiological; Uterus; Vasopressins

Maternal diabetes during pregnancy may cause lasting effects on the psychoneurological development in the offspring. The aim of the present study was to investigate possible effects of an intrauterine or neonatal exposure to a diabetic environment on behavior during infancy and adulthood. On days 4 and 6 of age, offspring of streptozotocin-diabetic rats emitted higher numbers of ultrasound calls compared to control offspring. Neonatally streptozotocin-treated rats explored their environment by diminished sniffing and rearing intensity compared to control rats. However, in adult life neither of these rat groups displayed behavioral differences compared to their respective control group. The results suggest that development of basic behavioral patterns in the rat proceed almost normally despite exposure to a diabetic environment in the early embryonic period or in early infancy.

Topics: Animals; Animals, Newborn; Behavior, Animal; Blood Glucose; Body Weight; Brain Chemistry; Diabetes Mellitus, Experimental; Female; gamma-Aminobutyric Acid; Male; Maternal-Fetal Exchange; Nerve Growth Factors; Pregnancy; Pregnancy in Diabetics; Rats; Rats, Inbred Strains; Vasopressins

Frequency-responses curves for nerve stimulation and dose-response curve for norepinephrine, 5-hydroxytryptamine potassium chloride, vasopressin and acetylcholine (ACh) were determined in isolated, perfused mesenteric vascular beds from young (approximately 5 weeks) spontanelouly hypertensive (SHR) and Wistar Kyoto rats. Although mean systolic blood pressure (measured by tail cuff plethysmography) was slightly higher in the SHR, this difference was not significant. Slopes and maximum responses were increased significantly for nerve stimulation and all agonists. The basal perfusion pressure was also significantly elevated in the SHR. These differences are consistent with existing evidence that structural changes occur in blood vessels of SHR at an early stage and probably precede development of hypertension. Such structural changes could therefore contribute to development of the hypertension. Cocaine (1 microM) markedly increased responses to nerve stimulation and bolus injections of norepinephrine in preparations from SHR with little or no effect on such responses in Wistar Kyoto preparations, a result consistent with the known greater density of noradrenergic nerves in SHR vasculature. In the presence of cocaine, there was unmasked a selective super-sensitivity (significantly lower ED50) to norepinephrine in the SHR. Thus SHR mesenteric vessels may possess an alteration in adrenoreceptors or their coupling to other cellular mechanisms. Responses to ACh revealed no indication of a deficient endothelial mediated relaxation. An altered media:lumen ratio of small arteries, hypernoradrenergic innervation and supersensitivity to the transmitter may contribute to development of hypertension.

Topics: Animals; Animals, Suckling; Blood Pressure; Body Weight; Dose-Response Relationship, Drug; Male; Norepinephrine; Potassium Chloride; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Serotonin; Species Specificity; Splanchnic Circulation; Vasopressins

Adaptations to the effects of clonidine (CL) and rilmenidine (R) were studied during a 12-week training program (swimming) in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. Systolic blood pressure (SBP) was regularly measured during this period. Body weight (BW) was determined at the beginning and at the 12th week. Plasma parameters, cardiac determinations, vasopressin (pAVP), and plasma renin activity (PRA) were measured only at the end of the experiment. Both SBP and ponderal benefit were reduced by CL, R, and training. Contrary to beta-adrenoceptor blocking agents, we found no inhibition of the beneficial effect on SBP of training in combination with CL or R. Plasma and hypothalamic vasopressin were reduced by both drugs but only CL increased plasma renin activity (PRA) although its mechanisms of action are still not clearly understood. Our results suggest that CL and R as well as swim training can be considered as an effective countermeasure in SHR. Moreover, the heterogeneity of action of CL and R on some of the parameters tested is in favor of different pharmacological properties for these drugs.

Topics: Adrenergic alpha-Agonists; Animals; Blood Pressure; Body Weight; Clonidine; Electrolytes; Heart; Male; Organ Size; Oxazoles; Physical Conditioning, Animal; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Renin; Rilmenidine; Swimming; Vasopressins

No study has, to our knowledge, evaluated the acute effects of low immunosuppressive doses of cyclosporin (CsA) on renal function. To establish whether a relationship exists between the dosage of CsA and the onset of nephrotoxicity, 28 rats were studied by renal clearances before (control) and after i.v. administration of different doses of CsA: 3 mg/kg b.w. (group 1); 7 mg/kg b.w. (group 2); 11 mg/kg b.w. (group 3); 15 mg/kg b.w. (group 4). No change in renal function was observed between control and the post-CsA period in groups 1 and 2. GFR (inulin clearance) was decreased vs the control period in group 3 and group 4 (-22% and -37%, respectively, P less than 0.001); the difference between these two groups was statistically significant (P less than 0.01). Effective renal plasma flow (PAH clearance) was similarly decreased in groups 3 and 4 vs their control periods (-21% and -28%, respectively, P less than 0.001) due to the increase of total renal vascular resistance (+41% and +42%, respectively, P less than 0.001). Filtration fraction was significantly decreased by CsA in group 4 (P less than 0.01 vs the control period). PAH renal extraction, urinary volume, and sodium and potassium excretion were similar in all groups before and after CsA. PRA and ADH were significantly increased only in group 4 (P less than 0.01) vs the baseline values. A high and significant relationship was detected between CsA dosage and the decrease of GFR (r = 0.81, P less than 0.001) and RPF (r = 0.612, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Acute Disease; Animals; Blood Pressure; Body Weight; Cyclosporins; Glomerular Filtration Rate; Hematocrit; Kidney Diseases; Male; Potassium; Rats; Rats, Inbred Strains; Renal Circulation; Sodium; Vasopressins

In order to resolve conflicting reports in the literature on the effect of aging on the hypothalamo neurohypophyseal system (HNS) in rats, multiple parameters associated with the HNS were evaluated in young (4 months), fully mature (14 months), and old (25 months) Fischer 344 rats under basal and stimulated conditions. The hypothalamic hormones oxytocin and vasopressin were compared in radioimmunoassay of serum, urine, brain and pituitary. Information on body weight, water intake, urine output, serum hematocrit and plasma osmolality was also obtained from the same subjects and analyzed together with these data. Finally, semi quantitative histofluorescence assessment of the noradrenergic innervation of the mediobasal hypothalamus from the same animals was performed to determine the extent of central afferent input to the HNS with advancing age. The circulating levels of vasopressin and oxytocin did not significantly differ in the three age groups under basal conditions. Serum vasopressin concentration was increased following water deprivation, and the increase was comparable in all age groups. Serum oxytocin was also increased following water deprivation in all groups, but the increase was greater in the 25-month-old rats relative to the 4-month-old rats. Urinary excretion of vasopressin was used as an index of daily vasopressin secretion. The urinary concentration of vasopressin was less in aged rats relative to young controls, though an increased urine volume in the mature and old animals meant that total vasopressin excretion in the urine was comparable at all ages studied. The increased urine volume in the mature and aged rats does not appear to reflect a decrease in renal sensitivity to vasopressin, since all age groups demonstrated a comparable reduction in urine volume during water deprivation, at comparable concentrations of circulating vasopressin. These data suggest that the increase in urine volume observed in the 14- and 25-month-old rats may be a function of increased fluid intake rather than hyperactivity in the HNS. The concentrations of both peptides were reduced in the posterior pituitary of aged rats, though again, the total amount of peptide in the gland did not change. Only oxytocin showed an age-related change in the hypothalamus, decreasing in the oldest subjects. These data indicate that the ability to secrete adequate quantities of vasopressin in response to dehydration is not compromised in Fisher 344 rats up to 25 months of age.

Topics: Aging; Animals; Body Weight; Catecholamines; Drinking; Hematocrit; Male; Microscopy, Fluorescence; Osmolar Concentration; Oxytocin; Paraventricular Hypothalamic Nucleus; Pituitary Gland, Posterior; Radioimmunoassay; Rats; Rats, Inbred F344; Supraoptic Nucleus; Vasopressins

Plasma immunoreactive human atrial natriuretic peptide (hANP) levels were measured in 9 patients with chronic renal failure treated with maintenance hemodialysis in order to evaluate the effects of fluid removal and osmotic pressure. Under hemodialysis without fluid removal plasma hANP levels remained unchanged, but the levels were significantly decreased during extra-corporeal ultrafiltration (p less than 0.01). The present study provided strong evidence that the fall in plasma hANP levels in hemodialysis patients is mainly due to the reduction in circulating plasma volume.

Topics: Adult; Aged; Atrial Natriuretic Factor; Body Weight; Extracorporeal Circulation; Female; Humans; Kidney Failure, Chronic; Male; Middle Aged; Renal Dialysis; Ultrafiltration; Vasopressins

1. Partial (5/6) renal ablation was performed in Long Evans rats treated with vehicle or a vasopressin V1-receptor antagonist, in control Long Evans rats, and in homozygous Brattleboro rats which lack endogenous vasopressin. 2. In control and vasopressin-blocked Long Evans rats, 3 weeks following partial renal ablation, systolic blood pressure was 215 +/- 5 and 199 +/- 9 mmHg and, urinary protein excretion was 54 +/- 4 and 50 +/- 3 mg day-1, respectively. 3. The pressor response to exogenous vasopressin was significantly (P less than 0.05) reduced in rats treated with the V1-receptor antagonist (ED50 mmHg 5.0 +/- 1.6 vs. 0.09 +/- 0.01 micrograms kg-1). 4. In control Long Evans and in Brattleboro rats, 3 weeks following renal ablation, systolic blood pressure was 204 +/- 10 and 191 +/- 7 mmHg, and urinary protein excretion was 97 +/- 27 and 71 +/- 5 mg day-1, respectively. 5. Histological examination of the remaining kidney tissue demonstrated significant glomerular hyalinization following renal ablation but no differences between any of the groups. 6. The data indicate that neither vasopressin nor the urinary concentrating mechanism is likely to be involved in the hypertension and proteinuria associated with partial renal ablation.

Topics: Animals; Blood Pressure; Body Weight; Hypertension, Renal; Kidney; Kidney Failure, Chronic; Kidney Glomerulus; Male; Osmolar Concentration; Proteinuria; Rats; Rats, Brattleboro; Urodynamics; Vasopressins

To assess the roles of vascular prostaglandins in the hypertension of chronic renal failure, the release of prostacyclin and thromboxane (TX) from aorta was evaluated in male Sprague-Dawley rats, the renal mass of which was reduced by removing one kidney and two-thirds of the contralateral kidney ("5/6 nephrectomy"). Five-sixths nephrectomy was followed by significant rises in serum creatinine to 0.55 +/- 0.03 mg/dl and urea nitrogen to 42.9 +/- 3.8 mg/dl, with a concomitant rise in mean blood pressure from 121.6 +/- 1.6 mmHg to 155.3 +/- 8.4 mmHg. In 5/6 nephrectomized rats, the release of TX A2 from aorta, as measured by its stable metabolite TX B2, increased by 60% (p less than 0.01) and prostacyclin, as measured by its stable metabolite 6-keto-prostaglandin, F1 alpha (6-keto-PG F1 alpha) increased by 51% (p less than 0.05). The amounts of both TX B2 and 6-keto-PG F1 alpha released from aorta were closely related to the height of mean blood pressure. These results suggest that the enhanced vasoconstrictor TX production in the vascular walls may be relevant to hypertension in rats with subtotal renal ablation. The adaptive increase in prostacyclin production in the vascular walls may compensate for the elevation of blood pressure due to chronic renal failure in this animal model.

Topics: Animals; Aorta; Blood Pressure; Body Weight; Epoprostenol; Hypertension, Renal; Kidney; Male; Nephrectomy; Rats; Rats, Inbred Strains; Thromboxanes; Vasoconstrictor Agents; Vasopressins

To evaluate the role of vasopressin in the regulation of atrial natriuretic peptide (ANP) secretion, the plasma, atrial, ventricular, and hypothalamic levels of ANP were measured in Long-Evans (LE) and vasopressin-deficient Brattleboro (DI) rats. Total atrial immunoreactive ANP (IR-ANP) as well as right auricular IR-ANP concentration were higher in the DI than in the LE rats, whereas no significant difference was noted in left auricular IR-ANP concentration. In the left ventricle of DI rats, the IR-ANP concentration was 82% greater than that in the LE rats, while no substantial difference was found in the right ventricular IR-ANP concentration between the strains. Normal LE rats had low levels of left ventricular ANP mRNA and barely detectable ANP mRNA in the right ventricle, DI rats showed a 3-fold greater ANP mRNA concentration in the left ventricle than age-matched LE controls, and ANP mRNA levels were also increased in the left auricle of DI rats. The hypothalamic IR-ANP content, but not the concentration, was significantly increased in the DI compared to the LE rats. Despite increased cardiac IR-ANP and ANP mRNA levels, plasma IR-ANP concentrations were similar in the conscious DI rats (97 +/- 9 pg/ml; n = 13) and the LE rats (95 +/- 8 pg/ml; n = 15). Volume expansion (1.1 ml/100 g BW of 0.9% saline, iv) increased right atrial pressure and caused a significant rise in plasma IR-ANP in both strains (P less than 0.01). Elevations of plasma IR-ANP concentrations caused by volume loading were comparable in LE and DI rats in either the absence or presence of exogenous vasopressin (5 ng/kg.min, iv), which, when infused alone, did not significantly influence the plasma IR-ANP concentration. However, the relation between the change in IR-ANP concentration and the change in right atrial pressure shifted to the left, and thus, for a given increase in right atrial pressure, a greater amount of IR-ANP was released in the vasopressin-treated rats than in the control animals. These results demonstrate that although acute volume expansion does not necessarily require endogenous vasopressin for the ANP secretory response, vasopressin increased the ability of volume expansion to induce ANP release, thus modulating the direct mechanical stimulus-induced ANP secretion. The increased left ventricular levels of immunoreactive ANP and augmentation of ANP mRNA levels in Brattleboro rats despite normal left ventricular weight to body weight ratio show that increased ANP gen

Topics: Animals; Atrial Natriuretic Factor; Body Weight; Heart Atria; Heart Ventricles; Hemodynamics; Hypothalamus; Male; Myocardium; Organ Size; Plasma Substitutes; Radioimmunoassay; Rats; Rats, Brattleboro; Rats, Inbred Strains; Rats, Mutant Strains; RNA, Messenger; Vasopressins

Previous experiments in Brattleboro rats with hereditary diabetes insipidus revealed that absence of ADH led to several alterations in kidney anatomy, which could be reversed by chronic ADH treatment. Present experiments were undertaken to determine if similar alterations were observable in normal Wistar rats when endogenous ADH level was varied by manipulating water intake or when exogenous ADH was infused. Water intake was increased by giving food with a high water content ad libitum and offering 5% glucose solution to drink (HWI rats), or decreased by reducing water intake to 1/3 of spontaneous intake (RWI rats). An additional group received chronic ADH infusion with Alzet osmotic minipumps (ADH rats). Results were compared to those obtained in control rats (CON) drinking ad libitum. RWI, CON, and ADH rats ate dry pellets ad libitum. After 6 weeks on these regimens kidneys were perfusion fixed and serial sections were cut for morphometric measurements by light microscopy. Results in the four groups showed that kidney weight relative to body weight was influenced by the operation of urinary concentrating mechanism, with HWI less than CON less than RWI less than ADH. The increase in kidney weight in rats with high urine concentration was not homogeneously distributed throughout the different kidney zones and the different nephron segments. The inner stripe of the outer medulla (IS) increased more in relative height and volume than other kidney zones and, within this zone, the volume of epithelium of thick ascending limb of Henle's loops (TAL) increased more than expected from the whole kidney weight increase. In outer stripe of outer medulla (OS) and in cortex (C), TAL hypertrophy was equal to or lower than expected from whole kidney weight increase. Collecting duct epithelium in C, OS, and IS increased in proportion to whole kidney weight. The MTAL hypertrophy in IS was due to an increase in size of preexisting cells, except in the ADH group where an increase in cell number was also observed. Internephron heterogeneity with regard to glomerular size was greater in RWI and ADH than in CON and HWI rats. The marked hypertrophy of the deep TAL in the IS of rats in which urine concentration was stimulated could be related to an increase in salt transport in this nephron segment, triggered both by a direct stimulation by ADH, and by an increased salt recycling. The elongation of the inner stripe provides a greater length for the operation of the countercurren

Topics: Animals; Body Weight; Drinking; Female; Kidney; Kidney Concentrating Ability; Kidney Glomerulus; Organ Size; Rats; Rats, Inbred Strains; Vasopressins

Changes in osmoregulation during normal menstrual cycle were examined in 15 healthy women. In 10 women, studied repetitively during two consecutive menstrual cycles, basal plasma osmolality, sodium, and urea decreased by 4 mosmol/kg, 2 meq/l, and 0.5 mM, respectively (all P less than 0.02) from the follicular to luteal phase. Plasma vasopressin, protein, hematocrit, mean arterial pressure, and body weight did not change. In five other women, diluting capacity and osmotic control of thirst and vasopressin release were assessed in follicular, ovulatory, and luteal phases. Responses of thirst and/or plasma vasopressin, urine osmolality, osmolal and free water clearance to water loading, and infusion of hypertonic saline were normal and similar in the three phases. However, the plasma osmolality at which plasma vasopressin and urine osmolality were maximally suppressed as well as calculated osmotic thresholds for thirst and vasopressin release were lower by 5 mosmol/kg in the luteal than in the follicular phase. This lowering of osmotic thresholds for thirst and vasopressin release, which occurs in the luteal phase, is qualitatively similar to that observed in pregnancy and should be taken into account when studying water balance and regulation of vasopressin secretion in healthy cycling women.

Topics: Adult; Blood Pressure; Blood Proteins; Body Weight; Estrogens; Female; Hematocrit; Humans; Luteinizing Hormone; Menstrual Cycle; Progesterone; Reference Values; Sodium; Thirst; Urea; Vasopressins; Water-Electrolyte Balance

Plasma concentrations of thyrotrophin (TSH), thyroxine (T4), and triiodothyronine (T3), and pituitary TSH concentrations were determined at weekly intervals during the first 42 days following birth in Brattleboro homozygous (DI), Brattleboro heterozygous (HZ), and Long-Evans (LE) rats. Offspring from matings of Brattleboro rats were divided into DI and HZ animal subgroups on the basis of hypothalamic vasopressin content. In control LE rats, circulating levels of TSH, T4, and T3, and pituitary TSH concentrations increased during the early postnatal period to reach relatively stable levels between 28 and 42 days of age. In DI and HZ rats, the thyroid axis developed in parallel to that of LE rats during initial postnatal weeks. However, by 42 days of age, pituitary TSH concentrations were clearly elevated in Brattleboro rats relative to levels in age-matched LE animals. These data indicate that differences in thyroid axis function between Brattleboro and LE rats occur only after the attainment of a degree of maturity.

Topics: Animals; Body Weight; Female; Heterozygote; Homozygote; Hypothalamus; Male; Pituitary Gland; Radioimmunoassay; Rats; Rats, Brattleboro; Rats, Mutant Strains; Sex Factors; Thyroid Gland; Thyrotropin; Thyroxine; Triiodothyronine; Vasopressins

Vasopressin has been studied intensively in DOCA-salt rats and seems to play an important role in this model of hypertension. In the present study we investigated plasma vasopressin in seven normotensive young volunteers during the early phase of mineralocorticoid-induced hypertension. We administered 0.8 mg/day fludrocortisone for 1 week. Body weight, blood pressure, plasma vasopressin, plasma osmolality and electrolytes, as well as plasma renin activity, were evaluated on days 0, 3 and 7. Blood pressure increased significantly from 117/67 to 121/76 mmHg (P less than 0.05) within 1 week, while plasma osmolality remained unaltered at 284 +/- 3 mOsmol/l. Plasma vasopressin (0.45 +/- 0.1 pg/ml) was increased after 3 days (0.68 +/- 0.5 pg/ml) and rose further to 1.53 +/- 0.27 pg/ml after 1 week (P less than 0.05). Changes in plasma vasopressin concentration were not correlated with alterations in blood pressure. Our results show an increase in plasma vasopressin in the early phase of mineralocorticoid-induced hypertension in man. However, the observed increase is moderate and does not seem to explain the increase in blood pressure alone, but could contribute to the blood pressure increase during mineralocorticoid treatment.

Topics: Adult; Body Weight; Fludrocortisone; Humans; Hypertension; Male; Osmolar Concentration; Renin; Sodium; Vasopressins

Vasopressin (AVP) in acute experiments has been shown to influence cardiovascular reflexes, but the effect of a more prolonged administration of AVP on the sympathetic nervous system has not been investigated. Long-Evans rats were treated for 7 days with AVP (Pitressin tannate in oil, with single daily doses of 100 or 500 mU.100 g-1, s.c.) to determine whether AVP alters norepinephrine (NE) turnover in kidney, intestine, or skeletal muscle. Control rats were given equal doses of peanut oil daily. NE turnover was determined by measuring the decline in tissue levels of NE for 8 h after inhibition of tyrosine hydroxylase with alpha-methyl-p-tyrosine (300 mg.kg-1, i.p. every 4 h). Measurements of water intake, urine output, and urine osmolality showed that chronic administration of the high dose, but not the low dose, of AVP produced maintained increases in urine osmolality and decreases in water intake and urine output. Body weight, plasma osmolality, plasma electrolytes, and hematocrit were not significantly altered by AVP treatment, but mean arterial pressure was elevated significantly (control, 105 +/- 3 mmHg versus AVP, 119 +/- 4 mmHg, p less than 0.05) (1 mmHg = 133.3 Pa) in the high dose group. Plasma renin activity was decreased slightly, but significantly in rats treated with the high dose of AVP. Compared with results in control animals, there were no statistically significant changes in NE turnover after chronic administration of either the low or the high dose of AVP. The results indicate that administration of AVP for 7 days to rats in normal fluid balance does not result in a decrease in NE turnover in peripheral organs.

Topics: Animals; Blood Pressure; Body Fluids; Body Weight; Drinking; Female; Heart Rate; Norepinephrine; Rats; Vasopressins

We describe three patients who have polydipsia and polyuria due to an abnormality in the osmoregulation of thirst. The clinical manifestations of the syndrome are similar to those of neurogenic diabetes insipidus. Thus, under basal conditions the patients have thirst, normal to high normal levels of plasma osmolality, and low levels of plasma vasopressin. Moreover, antidiuretic therapy greatly reduces thirst and polydipsia as well as polyuria. The only clinically distinguishing feature of the response is that thirst and water intake decrease less rapidly than water excretion. As a consequence, the patients with this syndrome develop variable degrees of dilutional hyponatremia and hypoosmolemia during treatment. The plasma vasopressin response to osmotic stimulation is relatively normal. In most of the patients, the osmotic threshold for vasopressin release is at the upper limit of normal, but this finding only explains their modest elevation in basal plasma osmolality. Thirst and water intake also change as a function of plasma osmolality. However, the threshold or "set" of the thirst osmostat appears to be abnormally low. The degree of downward resetting varies from patient to patient, but is always sufficient to stimulate thirst and water intake at levels of plasma osmolality below the normal range. This abnormality can account not only for the thirst and polyuria under basal conditions but also for the overhydration that occurs during antidiuretic therapy. The pathogenesis of the osmoregulatory abnormality is unknown but may be due to disruption of one or more of the afferent pathways that regulate the "set" of the thirst and vasopressin osmostats.

Topics: Adult; Body Weight; Deamino Arginine Vasopressin; Diabetes Insipidus; Drinking; Female; Humans; Male; Syndrome; Thirst; Urine; Vasopressins; Water-Electrolyte Balance

In the European hamster (Cricetus cricetus,L.) pinealectomy as well as a constant high level of either circulating melatonin or 5-methoxytryptamine induced marked changes in the immunocytochemically demonstrable central vasopressinergic innervation. When compared to control animals, a drastic decrease of AVP-immunoreaction was observed in the diagonal band of Broca, the lateral septum, the medial amygdala and the ventral hypothalamus. The results obtained suggest that part of the central vasopressinergic innervation is involved in pineal dependent seasonal functioning of the animal.

Topics: 5-Methoxytryptamine; Animals; Body Weight; Brain; Cricetinae; Male; Melatonin; Organ Size; Pineal Gland; Testis; Tryptamines; Vasopressins

The Brattleboro rat has severe diabetes insipidus due to an autosomal recessive trait resulting in the inability to synthesize detectable amounts of hypothalamic vasopressin. To determine whether this abnormality is due to a regulatory defect in the Brattleboro rat's vasopressin gene, we studied changes in the hypothalamic content of vasopressin mRNA in normal Long-Evans and homozygous Brattleboro rats subjected to osmotic stress and correlated these changes with systemic responses to water deprivation. We report that the Brattleboro rat does have a marked defect in the regulation of vasopressin gene expression consisting of an inability to increase hypothalamic vasopressin mRNA content in response to severe osmotic stress.

Topics: Animals; Body Weight; Gene Expression Regulation; Hypothalamus; Osmolar Concentration; Oxytocin; Rats; Rats, Brattleboro; Rats, Inbred Strains; Rats, Mutant Strains; RNA, Messenger; Vasopressins; Water Deprivation

Accurel polypropylene/collodion controlled drug-delivery devices containing 22 micrograms [3H]vasopressin (VP) were implanted s.c. in VP-deficient Brattleboro rats. This caused a decrease in their urine production for at least 50 days, at which time the Accurel device was removed. Release of VP was followed by measurements of tritium radioactivity and by radioimmunoassay of VP in the urine. These parameters showed a constant pattern during the whole period. After re-implantation of the Accurel devices in another group of Brattleboro rats, release of VP continued to give the same level of urine production as during the last period of the first implantation. It is concluded that release of VP in-vivo is not influenced by encapsulation of the Accurel polymer by connective tissue, or that adaptation of the kidney adds to the maintenance of the urine production at this low level. In-vivo release rate is calculated to be about 1% of the original load each day. The in-vitro release in a flow cell system appeared to produce the same release rate which indicates that these data have a predictive value for the in-vivo situation.

Topics: Animals; Body Weight; Collodion; Drug Implants; Male; Polymers; Rats; Rats, Brattleboro; Vasopressins

Enkephalins are found in the posterior pituitary, can alter vasopressin secretion, and have greater pressor effects in spontaneously hypertensive rats (SHR) than in Wistar-Kyoto (WKY) rats. Measurement of the plasma methionine-enkephalin concentration (PMet-Enk) has provided equivocal results in humans and has not been reported in rats. We have developed a highly specific and sensitive Met-Enk radioimmunoassay and determined that Met-Enk circulates in rats but that PMet-Enk is no different between SHR and WKY rats (7.6 +/- 0.8 and 9.2 +/- 0.8 pg/ml, respectively). Water deprivation for 48 h increased the plasma vasopressin concentration (PADH) and 24-h urinary vasopressin excretion (UADHV) in SHR and WKY rats, but PMet-Enk was not altered. There were no differences in PADH and UADHV between SHR and WKY rats in either the euhydrated or dehydrated state. These results suggest that it is unlikely that circulating Met-Enk contributes importantly to the maintenance of hypertension in SHR. There was also no evidence for a greater secretion of vasopressin in SHR than in WKY rats, in contrast to previous reports.

Topics: Animals; Blood Pressure; Body Weight; Dehydration; Diuresis; Enkephalin, Methionine; Heart Rate; Hypertension; Male; Osmolar Concentration; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Sodium; Vasopressins

Although the steps involved in biosynthesis and secretion of the neuropeptide vasopressin (AVP) have been extensively studied, the factors which regulate AVP gene expression remain unknown. Therefore, we sought to determine the dynamics of AVP mRNA accumulation in response to a strong stimulus for AVP release, i.e. during salt imbibition and the ensuing period of rehydration. AVP mRNA levels were determined in terms of absolute amounts by a novel quantitative densitometric hybridization assay, using in vitro synthesized sense-strand RNA as a quantitative standard and complementary anti-sense RNA as a specific probe. The template used for RNA transcription consisted of a 196-base pair genomic DNA fragment corresponding to exon C of the rat AVP gene. Determination of basal hypothalamic AVP mRNA levels yielded 12.5 +/- 2.7 fmol/hypothalamus. Salt imbibition, which induced a 6% rise in blood osmolality and an 82% loss of pituitary AVP, resulted in a 3-fold increase of AVP mRNA to 35 +/- 5 fmol/hypothalamus. Following rehydration, plasma osmolality returned to control levels by day 2, pituitary AVP by day 6, and hypothalamic AVP by day 14. By contrast, AVP mRNA levels remained significantly elevated throughout the 30-day rehydration period. Furthermore, pituitary AVP reached a level of 177% of control by day 14 of rehydration. These data show that osmotic stimulation results in a long-lasting elevation of hypothalamic AVP mRNA; during rehydration, these elevated mRNA levels direct AVP biosynthesis at a rate which surpasses secretory demands; AVP mRNA accumulation does not appear to be directly regulated by either pituitary or hypothalamic AVP. Therefore, either an unusually long half-life of greater than or equal to 7 days must be assumed for AVP mRNA or, alternatively, a continued stimulation of AVP gene transcription must occur, even in the absence of a secretory stimulus and following complete repletion of cellular AVP stores.

Topics: Animals; Body Weight; Gene Expression Regulation; Hypothalamus; Male; Neurons; Osmolar Concentration; Osmosis; Pituitary Gland; Rats; Rats, Inbred Strains; RNA, Messenger; Vasopressins

This study was designed to investigate relationships between dietary potassium and the renal prostaglandin system in rats. The potassium content of the diet was 0.162 mmol/g during the control period and 0.004, 0.162, 1.351, or 2.702 mmol/g during the experimental period. Relative to control data in rats fed a 0.162 mmol/g potassium diet, the urinary excretion of 6-keto-PGF1 alpha was not affected by high potassium intake but increased (P less than 0.05) by 25% in rats fed a low potassium diet for 13 days and was associated with reduction of plasma potassium and with elevation of both plasma renin and net release of 6-keto-PGF1 alpha from renal inner medulla slices incubated in Krebs solution. The excretion of PGF2 alpha was not affected by low potassium intake but increased (P less than 0.05) by about twofold in rats fed a potassium-rich diet (1.351 and 2.702 mmol/g) for 13 days and was associated with elevation of plasma potassium concentration, renal prostaglandin 9-keto-reductase activity, and urinary excretion of kallikrein and vasopressin. The urinary excretion of PGE2 was not altered in rats fed either low or high potassium diets. Altogether, these results indicate selective influence of dietary potassium on the urinary excretion of prostaglandins in the rat.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Body Weight; Diet; Dinoprost; Dinoprostone; Hydroxyprostaglandin Dehydrogenases; Kallikreins; Kidney; Male; Potassium; Prostaglandins E; Prostaglandins F; Rats; Rats, Inbred Strains; Renin; Vasopressins; Water-Electrolyte Balance

To elucidate the effect of bed rest used as an adjunct to increased diuretic treatment, twelve patients with chronic congestive heart failure (CHF) had a 50% increase in loop diuretic dosage and were allocated to either continuous bed rest or bed rest during nights only. The 24-hour bed rest group reduced their weight significantly (mean +/- SEM: 2.00 +/- 0.79 kg, P less than 0.001), whereas the night bed rest group had no significant weight reduction (1.10 +/- 0.37 kg, 0.1 less than P less than 0.2) during three days of observation. Furthermore, the 24-hour bed rest group had a significantly increased diuresis (P less than 0.05) during the first day of the study and a tendency towards increased natriuresis. The cumulated diuresis for the two groups (24-hour bed rest versus night bed rest) during the three days of study were 7773 +/- 700 ml and 5861 +/- 909 ml (0.05 less than P less than 0.1), respectively. Plasma concentrations of adrenaline, noradrenaline, renin and aldosterone were increased, as measured in the supine position. No significant differences were found between the two groups. Plasma concentrations of antidiuretic hormone were within normal limits. In conclusion, continuous bed rest is a reasonable adjunct to diuretic treatment in patients with CHF.

Topics: Adult; Aged; Aldosterone; Bed Rest; Body Weight; Chronic Disease; Combined Modality Therapy; Diuretics; Epinephrine; Female; Heart Failure; Humans; Male; Middle Aged; Natriuresis; Norepinephrine; Posture; Prospective Studies; Renin; Vasopressins

We examined renal function and Na+ balance in a patient with congestive heart failure who was treated with demeclocycline (DMC) on three separate occasions under strict metabolic balance conditions. Natriuresis and reversible renal insufficiency, which could not be explained solely on the basis of negative Na+ balance, developed on each occasion. In contrast to reports of an association between elevated serum DMC levels and renal insufficiency in patients with cirrhotic edema, the renal insufficiency in this patient with cardiac edema occurred in the absence of high DMC levels. Consequently, markedly elevated serum DMC levels do not appear to be a prerequisite for the development of natriuresis or renal insufficiency in edematous patients receiving this drug. In an attempt to clarify the mechanism of the natriuresis, we also examined the effects of DMC on Na+ transport in an in-vitro model system, the toad urinary bladder. DMC inhibited aldosterone-stimulated Na+ transport, but had no effect on Na+ transport when the latter was jointly stimulated by ADH and theophylline. Despite this selective inhibition of the natriferic effect of aldosterone in vitro, it is unlikely that such a mechanism completely accounts for the natriuresis observed in-vivo since the natriuresis is generally of large magnitude and is usually accompanied by some degree of kaliuresis, and DMC had no consistent effect on urinary aldosterone excretion. Consequently, other mechanisms must be sought to explain the natriuretic effect of DMC in edematous patients. Likewise, mechanisms other than negative Na+ balance (perhaps primary alterations in renal hemodynamics) must underly the development of renal insufficiency in such individuals.

Topics: Administration, Oral; Aldosterone; Animals; Anura; Biological Transport; Blood Urea Nitrogen; Body Weight; Demeclocycline; Glomerular Filtration Rate; Heart Failure; Humans; In Vitro Techniques; Kidney Failure, Chronic; Male; Middle Aged; Natriuresis; Nephrons; Potassium; Sodium; Theophylline; Vasopressins

Age-related changes in the intake of food and water, and the output of faeces and urine were investigated in C57BL/Icrfat mice of 6 and 24 months of age. Animals were singly housed in a metabolic cage for a period of 30 days. 14 days were allowed for acclimatization before the animals were dehydrated for 24 hours. 10 days of rehydration were allowed prior to a hyperosmotic challenge with 3% sodium chloride in the drinking water. The animals were then observed for 5 more days of rehydration. Urine was collected and analysed with regard to sodium, potassium, urea and vasopressin output/24 hours (/100g body weight), and the osmotic pressure of the urine was determined. Data were analysed by a 2 factor analysis of variance with repeated measures on one factor. Significant changes were detected in the control of body weight, potassium, sodium and urea outputs. No age-differences were detected in the intake of food or water, the output of faeces or urine, the urine osmotic pressure or the excretion of vasopressin. However, significant changes in these variables were detected in both age groups on the days of physiological challenge. The conclusion drawn is that in the mouse strain studied, and for the period of the lifespan investigated, there is no age related defect in the secretion of vasopressin. However, there are trends in the data suggesting a decreased responsiveness of the kidney with age.

Topics: Age Factors; Animals; Body Water; Body Weight; Drinking; Eating; Feces; Hypertonic Solutions; Kidney; Male; Mice; Mice, Inbred C57BL; Osmotic Pressure; Potassium; Sodium; Urea; Vasopressins; Water Deprivation; Water-Electrolyte Balance

Topics: Adult; Aged; Body Weight; Diagnosis, Differential; Extracellular Space; Female; Glucose; Glycogen; Humans; Hypernatremia; Intracellular Fluid; Kidney Concentrating Ability; Male; Middle Aged; Vasopressins; Water Loss, Insensible

Somatomedin serum levels of congenitally vasopressin-deficient Brattleboro rats were determined postnatally between day 1 and 55, and compared with heterozygous control values. Assays were performed with a radioimmunoassay of insulin-like growth factor 1 (IGF-1). A transient enhancement of immunoreactive IGF-1 levels between day 8 and 21 of age and a reduction in adulthood was found. This observation shows that the early growth impairments of the Brattleboro mutant are not due to a deficiency of IGF-1.

Topics: Animals; Body Weight; Female; Growth Disorders; Male; Radioimmunoassay; Rats; Rats, Brattleboro; Somatomedins; Vasopressins; Weaning

The origin of endogenous opioid peptides that inhibit release of vasopressin (VP) and oxytocin (OT) into the bloodstream after tail electroshock was investigated. We hypothesized that endogenous opioid peptides derived from the anterior pituitary reduced secretion of VP and OT during this stimulus. To test this hypothesis, dexamethasone (DEX) was used to preferentially suppress release of endorphins with ACTH from the anterior pituitary. We evaluated the effects of an opiate receptor antagonist, naltrexone, on the rise in plasma [VP] and [OT] after tail electroshock in male Sprague-Dawley rats given DEX either chronically or acutely before the shock. In the chronic study rats were injected SC daily with saline (3.2 ml/kg) or DEX (0.2 mg/kg) for 17 days. In the short term study, rats were injected IP with saline (5 ml/kg) or DEX (0.5 mg/kg) the day before and again 105 min prior to tail electroshock. Thirty min (chronic study) or 90 min (acute study) after saline or DEX was given on the last day, rats were injected SC with saline (1 ml/kg) or naltrexone (1 mg/kg). Fifteen min later, animals received tail electroshock (41 V, 30 sec) and were decapitated 15 sec after shock was completed. Control animals were treated similarly but not shocked. Amounts of VP and OT in plasma and the neurointermediate lobe were quantified by RIA. [VP] and [OT] were elevated in plasma of all rats given tail electroshock. Greater increases (p less than 0.05) in hormone concentrations were measured in plasma of shocked rats treated with DEX.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Body Weight; Dexamethasone; Electroshock; Hematocrit; Male; Naltrexone; Oxytocin; Pituitary Gland; Rats; Rats, Inbred Strains; Tail; Time Factors; Vasopressins

Water deprivation in gerbils and rats for 5 and 3 days respectively resulted in the same degree of dehydration of the animals and similar depletion of the neurohypophyseal vasopressin stores. Following access to drinking water, the vasopressin stores were replenished in the gerbil and rat in 2 and 6 days respectively. It was suggested that the quicker restoration of the store in the gerbil was due to the greater ability to synthesize vasopressin and to continuing high activity of the neurosecretory cells until the stores were replete.

Topics: Animals; Body Weight; Female; Gerbillinae; Hypothalamo-Hypophyseal System; Male; Rats; Species Specificity; Time Factors; Vasopressins; Water Deprivation

Arginine-vasopressin (AVP), the antidiuretic hormone, not only regulates water balance but may also exert direct and indirect effects on blood pressure by influencing systemic vascular resistance and body fluid volumes. Recently, specific competitive antagonists of AVP at its vascular and tubular receptors have been described. We used d(CH2)5Tyr(Me) AVP, a vascular (V1) antagonist, and d(CH2)5-D-Tyr(Et) VAVP, a vascular and tubular (V1V2) antagonist, for studies on the role of AVP in deoxycorticosterone acetate (DOCA)-salt hypertension. The antagonists were infused intravenously via osmotic minipumps in unilaterally nephrectomized rats for 6 weeks after the beginning of the DOCA-salt treatment. At the end of the experiment, blood pressure was 15 mm Hg lower in the rats receiving the V1 antagonist than in those in which the vehicle was infused. In the rats receiving the V1V2 antagonist, blood pressure was reduced by 38 mm Hg. However, these rats were in poor general condition and gained no body weight. Their plasma sodium concentration was markedly increased throughout the duration of the experiment. These results suggest that AVP contributes to the development of DOCA-salt hypertension not only through its vascular but also through its renal tubular effects. Thus AVP may act as an impormediator of volume changes associated with alterations in sodium intake or excretion and thereby affect blood pressure.

Topics: Animals; Body Water; Body Weight; Desoxycorticosterone; Endocrine Glands; Hematocrit; Hypertension; Male; Rats; Rats, Inbred Strains; Sodium; Vasopressins

The regulation of sodium metabolism and the renin-angiotensin-aldosterone system was evaluated during 24 h of water, but not food, deprivation and during rehydration in the dog. Dehydration caused increases in plasma concentrations of sodium (6.0 +/- 0.7 meq/l), protein (0.8 +/- 0.1 g/dl), vasopressin (5.3 +/- 0.9 pg/ml), and renin activity (3.5 +/- 1.1 ng AI X ml-1 X 3 h-1). Plasma aldosterone was unchanged and plasma potassium fell slightly (0.2 +/- 0.1 meq/l). During dehydration, food, and thus sodium intake fell by more than 10% in 12 of 19 dogs, but urinary sodium excretion increased significantly, leading to a negative sodium balance (1.9 +/- 0.2 meq/kg). Sodium retention was observed after rehydration and sodium balance; plasma electrolytes, vasopressin, and plasma renin activity (PRA) returned turned to control levels after the 1st day of recovery. However, plasma aldosterone was slightly elevated at this time, returning to control after the 2nd day of recovery. The dehydration-induced natriuresis could not be accounted for by a fall in plasma aldosterone. However, sodium retention following rehydration could be aldosterone dependent, because additional studies showed a threefold rise in plasma levels of the hormone 1 h after drinking. The acute rise in aldosterone correlated closely (r = 0.82) with the fall in plasma sodium after drinking but not with changes in adrenocorticotrophic hormone, PRA, or plasma potassium. It is concluded that natriuresis is a homeostatic response to dehydration as a means of ameliorating the rise in body fluid osmolality.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aldosterone; Animals; Body Fluids; Body Weight; Dehydration; Dogs; Female; Homeostasis; Male; Natriuresis; Osmolar Concentration; Potassium; Renin; Renin-Angiotensin System; Sodium; Vasopressins; Water Deprivation

Intact female rats implanted subcutaneously with Silastic tubes containing estradiol benzoate (EB) (28.7 micrograms X kg-1 X day-1) for 28 wk had a significantly greater daily intake of water, a higher water-to-food intake ratio, and a greater urine output than untreated control rats. Ovariectomized (OVX) rats also implanted for 14 wk with EB tubes (15 and 36 micrograms X kg-1 X day-1) showed identical results. Dipsogenic responses of the EB-treated rats to isoproterenol (25 micrograms/kg sc), angiotensin II (200 micrograms/kg ip), and hypertonic saline (1 M, 1% of body wt ip) were significantly attenuated. Both intact and OVX rats were subjected to a 24-h dehydration to assess renal concentrating ability. EB-treated rats lost significantly more weight and excreted significantly more urine of lower osmolality than controls. Administration of vasopressin to volume-loaded, EB-treated rats revealed no abnormalities in the ability to concentrate urine to the level of controls. Thus, in spite of a reduced responsiveness to several dipsogenic stimuli, EB-treated rats have an increased daily water turnover apparently related to an inability to concentrate their urine. This in turn may be related to abnormalities in either synthesis or release of antidiuretic hormone or both.

Topics: Angiotensin II; Animals; Body Weight; Castration; Diuresis; Drinking; Eating; Estradiol; Female; Isoproterenol; Kidney Concentrating Ability; Osmolar Concentration; Ovary; Rats; Rats, Inbred Strains; Saline Solution, Hypertonic; Time Factors; Vasopressins; Water Deprivation; Water-Electrolyte Balance

This study was designed to determine if vascular dysfunction and enhanced norepinephrine sensitivity occurring in early experimental juvenile diabetes (S. M. Mueller, T. M. Mueller, and P. J. Ertel, 1982, Amer. J. Physiol. 243, H139-H144) persist, improve, or worsen in adulthood. Alloxan was administered to rats at 4 weeks of age and they were studied 14 weeks later. After Seconal anesthesia, the hindquarters of diabetic and control rats were perfused at a constant flow rate per 100 g through the abdominal aorta with oxygenated Tyrode solution containing dextran. Efflux was from the ligated and severed inferior vena cava. In order to test the effect of a strong sympathetic stimulus producing reflex peripheral vasoconstriction, the cephalad portions of the rats were rapidly hemorrhaged. The time to the maximal increase was significantly longer in the diabetics (122 +/- 6 sec, P less than 0.05) than in the controls (102 +/- 5 sec) and the increase in perfusion pressure was markedly less in the diabetics (D) (48 +/- 9 mm Hg, P less than 0.01) than in the age-matched controls (C) (88 +/- 10 mm Hg). The threshold to norepinephrine in the perfusate was determined. The threshold was significantly lower in D than in age-matched C [0.112 +/- 0.026 (P less than 0.05) vs 0.265 +/- 0.057 micrograms/ml, respectively]. The maximum vasoconstrictor capacity of the vasculature was tested with supramaximal doses of vasopressin and was significantly lower in D than in C [190 +/- 10 (P less than 0.001) vs 284 +/- 15 mm Hg, respectively]. These data suggest that both vasculopathy and enhanced norepinephrine sensitivity persist in chronic uncontrolled experimental diabetes mellitus. However, when the severity of the abnormalities was compared to early experimental diabetes mellitus, mild improvement had occurred--an apparent adaptation to the diabetic state as the animal grew.

Topics: Aging; Animals; Blood Glucose; Blood Pressure; Body Weight; Diabetes Mellitus, Experimental; Fatty Acids, Nonesterified; Hemorrhage; Male; Norepinephrine; Rats; Rats, Inbred Strains; Vascular Resistance; Vasoconstriction; Vasodilation; Vasopressins

Adverse renal reaction during prolonged indomethacin therapy (1 week) was studied in 15 preterm infants with persistent ductus arteriosus (PDA), which was associated with an ineffective circulatory volume. Following the medication a decrease in diuresis and creatinine clearances together with an increase in urinary osmolality and body weight was observed. Determinations of selected vasoactive hormones, such as plasma renin activity (PRA), antidiuretic hormone (ADH), and renal and systemic prostaglandins, indicated a complex pathophysiological condition of renal hypoperfusion and antidiuretic excess. During the treatment with indomethacin an effective circulatory volume had been restored by closing the ductus, which was followed by hormonal normalization. Subsequently kidney function was recovering despite continued indomethacin therapy. Based on these observations, one may assume that prolonged indomethacin therapy for prevention of PDA relapses is probably of no further harm to kidney function once the ductus has been closed successfully.

Topics: Blood Volume; Body Weight; Ductus Arteriosus, Patent; Humans; Indomethacin; Infant, Newborn; Infant, Premature, Diseases; Kidney; Kidney Function Tests; Oliguria; Osmolar Concentration; Prostaglandins; Renin; Time Factors; Vasopressins

A case of tuberculous Addison's disease presenting with psychosis, profound hyponatraemia, and detectable plasma antidiuretic hormone is reported. Clinical and biochemical improvement after corticosteroid replacement was followed by relapse with further psychosis and inappropriate antidiuretic hormone secretion: both were promptly reversed by demethylchlortetracycline. The association of psychological symptoms with Addison's disease, the role of anti-diuretic hormone secretion in Addison's disease, and the inter-relationship between Addison's disease, psychosis and anti-diuretic hormone secretion are discussed.

Topics: Addison Disease; Body Weight; Demeclocycline; Fludrocortisone; Humans; Hydrocortisone; Inappropriate ADH Syndrome; Male; Middle Aged; Psychotic Disorders; Vasopressins; Water Intoxication

The absence of hydrostatic forces, which results in body fluid shifts, and the absence of deformation forces on normally load-bearing tissues, appear to cause the principal disturbances found during and after space flight in the cardiovascular, fluid and electrolyte, erythropoietic, musculoskeletal, and metabolic systems. These alterations produce reduced body fluid volume, reduced musculoskeletal mass, and alterations in basal metabolism, resulting in the following consistent findings of space flight: weight loss, altered body composition, decreased orthostatic tolerance, and a compromised ability to deal with physical activity after returning from a space-flight environment. Specific changes include alterations in hydration status, resulting in a relative dehydration, loss of body calcium stores with a concomitant increase in urinary hydroxyproline, skeletal muscular atrophy, and a negative energy balance after prolonged space flight. Numerous endocrine changes have been determined during space flight, but more sensitive assay developed recently will allow careful determination of other hormone levels, and measurement of some of the primary changes that occur during the first hours of space flight. These results will be integrated into a working systems model of the physiologic response to weightlessness.

Topics: Atrophy; Body Weight; Calcium; Energy Metabolism; Glomerular Filtration Rate; Humans; Kidney; Muscles; Posture; Space Flight; Vasopressins; Vitamin D; Water-Electrolyte Balance; Weightlessness

Magnocellular neurons in the supraoptic and paraventricular nuclei synthesize and release vasopressin and oxytocin in response to dehydration. Pinealectomy has been observed to decrease the distribution in the supraoptic nuclei of thiamine diphosphate-phosphohydrolase, an enzyme specific for the Golgi apparatus that correlates positively with neurosecretory activity. Based upon these studies we postulated that pinealectomy would alter the concentration of neurohypohysial hormones in plasma elevated by 48 hr of water deprivation. In addition, we investigated the possibility that pinealectomy would affect vasopressin concentration in another circumventricular organ, the subfornical organ (SFO) and in a adjacent fiber tract of the limbic system, the hippocampal commissure-fornix (HC-F). Adult, male, Sprague-Dawley rats exposed to a 12 hr light/dark cycle were either unoperated (controls; C), sham-operated (Sham; S) or pinealectomized (PX) three weeks prior to testing. Food and water consumption and urinary excretion of Na and K were measured for 7 days. On the fifth day, half of the animals in each treatment group (C, S, PX) were deprived of water for 48 hr. Animals were decapitated on day 8. Vasopressin and oxytocin in plasma were extracted using bentonite and acetone-ether, respectively, then quantified by radioimmunoassay. The SFO and HC-F were microdissected from each brain. Like tissues from 4 rats were pooled, homogenized in 0.1 N HCl, and centrifuged. The supernatant was neutralized and vasopressin was quantified by radioimmunoassay. Dehydration resulted in antidiuresis, increased urine concentrations of Na and K, a decreased ratio of Na:K in urine, and reduced food consumption of similar magnitudes in all groups (C, S, PX; p greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Body Weight; Dehydration; Eating; Hematocrit; Hippocampus; Light; Male; Neurosecretory Systems; Oxytocin; Pineal Gland; Rats; Rats, Inbred Strains; Subfornical Organ; Time Factors; Vasopressins

1. The effects of isolation on systolic blood pressure, heart rate and fluid and electrolyte balances were studied in rats with a congenital inability to synthesize vasopressin (Brattleboro strain) and in the normal parent strain (Long Evans). 2. There was no significant difference between the systolic blood pressures of Brattleboro rats and Long Evans rats while the animals were housed in groups, although the heart rates of the Brattleboro rats were significantly higher. 3. After 5 days of isolation in metabolism cages, systolic blood pressure was significantly increased in the Long Evans rats, but not in the Brattleboro rats. 4. Since there were no significant differences between the fluid and electrolyte balances of the two groups after 5 days of isolation, it is unlikely that the hypertension in the Long Evans rats was attributable to a renal action of vasopressin. 5. It is possible that vasopressin was involved in the development of isolation-induced hypertension by virtue of its pressor effects. Alternatively, the failure of Brattleboro rats to develop hypertension may have been due to some abnormality in these animals other than the lack of vasopressin.

Topics: Animals; Blood Pressure; Body Weight; Heart Rate; Male; Rats; Rats, Brattleboro; Social Isolation; Sodium; Time Factors; Vasopressins; Water; Water-Electrolyte Balance

Male and female Long Evan rats and Brattleboro rats with ADH-deficient diabetes insipidus were treated with lithium administered in the diet for 12 weeks. The plasma lithium level was about 1 mmol/l in all groups. Lithium caused polydipsia and polyuria and lowering of renal concentrating ability in normal rats. In rats with ADH deficiency lithium tended to increase water intake, but did not influence spontaneous urine osmolality or maximal urine osmolality during water deprivation. The results indicate that the renal concentrating defect caused by lithium in rats can be explained by ADH-blockade as the only mechanism. However, there is circumstantial evidence that lithium in addition may stimulate thirst mechanisms by an ADH-independent action.

Topics: Animals; Body Weight; Diabetes Insipidus; Drinking; Female; Kidney Concentrating Ability; Lithium; Male; Rats; Rats, Brattleboro; Rats, Inbred Strains; Vasopressins

Topics: Body Weight; Cardiotonic Agents; Humans; Vasopressins

Topics: Acute Disease; Adenoma; Adult; Body Weight; Diabetes Insipidus; Female; Humans; Male; Middle Aged; Pituitary Neoplasms; Postoperative Complications; Solubility; Vasopressins

In the rat, angiotensin II (AII), following specific interaction with sensitive central nervous system (CNS) receptors promotes release of vasopressin (ADH). We have examined the integrity of this chain of events by comparing the concentration, Bmax, and dissociation constant, Kd, in the CNS of Brattleboro rats (BB), a strain incapable of synthesizing ADH, with Long Evans (LE) control rats that can synthesize ADH. AII binding properties in the hypothalamic-thalamic-septal-midbrain (HTSM) area from young and old BB and LE, as well as systolic blood pressure, were determined. There was a reduction in the HTSM-AII receptor concentration of young BB when compared with young LE rats. Young BB had lower pressure than age and sex matched LE controls. Neither Bmax nor pressure was significantly different between older BB and LE. A decline in HTSM-AII receptor concentration with age observed with LE is consistent with observations in SHR and WKY rats. Parallel Scatchard plots obtained indicated the presence of a single class of CNS AII receptors. These data suggest that ADH synthesis and AII receptor concentration are partially interdependent and that the CNS AII-ADH system is redundant in the maintenance of blood pressure.

Topics: Aging; Animals; Body Weight; Brain; Diabetes Insipidus; Female; Kinetics; Male; Rats; Receptors, Angiotensin; Receptors, Cell Surface; Species Specificity; Vasopressins

The Brattleboro homozygous diabetes insipidus (HOM-DI) mutant rat, incapable of synthesizing the neuropeptide vasopressin, has an impaired body growth of which the severity depends upon the conditions of reproduction. The comparison of homogeneously genotyped litters of HOM-DI and heterozygous (HET-DI) control pups, delivered and nursed by HOM-DI females, was regarded to be the only experimental design that practically excludes other influences on growth differences than the mutation itself. In this breeding scheme the postnatal growth of the HOM-DI brain is impaired, and the weight deficit persists into adulthood. Regionally, the neonatal development of cerebellum and medulla oblongata is most affected, and only slightly that of the cerebral cortex. The other separately isolated parts of the the brain seem to be unaffected (olfactory bulbs, hypothalamus, hippocampus, colliculi and thalamus plus basal ganglia). Cerebellum appeared to be the most consistently affected brain area of the HOM-DI Brattleboro rat since, unlike in the case of cerebral cortex and medulla oblongata, the weight deficit persisted throughout life. Olfactory bulb growth, on the other hand, appeared to continue after the first month of life, resulting in an increased weight at day 180. Water content of cerebral cortex and cerebellum of HOM-DI adults appeared slightly higher and might be explained by the generation of different brain water regulation systems for HET- and HOM-DI Brattleboro rats. Protein and DNA estimations of cerebral cortex, cerebellum and olfactory bulbs of male brains during development and in adulthood reflect the differences as found for weight, indicating no obvious changes in cell densities. It is concluded after comparison with other types of brain growth malformations, that the HOM-DI Brattleboro brain has its own particular etiology. The possible involvement of the action of vasopressin is postulated and discussed.

Topics: Aging; Animals; Body Weight; Brain; Diabetes Insipidus; Female; Homozygote; Male; Organ Size; Organ Specificity; Rats; Rats, Mutant Strains; Sex Factors; Vasopressins

Eleven healthy subjects aged 18--26 years underwent intermittent heat stress in a sauna bath. Blood samples were taken immediately before, during and at various intervals after heat exposure for the measurement of antidiuretic hormone, osmolality and percentage change of plasma volume. Antidiuretic hormone was increased during, immediately after and 90 min after heat stress. Three hours after the heat stress period antidiuretic hormone returned to control values in spite of a significant increase in osmolality and a significant decrease in plasma volume. These results imply that other factors than ADH are responsible for the long-term homeostasis of water balance and plasma volume.

Topics: Adolescent; Adult; Blood Volume; Body Weight; Hot Temperature; Humans; Osmolar Concentration; Stress, Physiological; Time Factors; Vasopressins

Plasma vasopressin was measured in seven insulin-treated diabetics during 24 h of insulin withdrawal to determine: 1) if abnormalities of the neurohypophysial-renal axis contribute to the dehydration of uncontrolled diabetes mellitus; and 2) the factors causing elevated levels of vasopressin in diabetic ketoacidosis. During the 24 h period of insulin withdrawal, blood glucose rose from 6.7 +/- 1.0 to 20.7 +/- 2.4 mmol/l, whereas plasma vasopressin was 3.6 +/- 0.5 pg/ml initially and in four patients showed little change. Markedly elevated levels of plasma vasopressin (17.8, 19.8 and 26.6 pg/ml) were observed in three patients following the onset of hypovolaemia, nausea and/or vomiting which are known to stimulate vasopressin release. Free water clearance was negative throughout the study in all patients. Thirst was not noted despite marked hyperglycaemia (16.9 +/- 2.5 mmol/l) until a significant fall in body weight of 0.9 +/- 0.2 kg had occurred (p less than 0.005). We concluded that marked elevation of vasopressin results from non-osmotic stimulation and that the mechanisms of body water conservation are overridden by the glycosuric diuresis.

Topics: Adult; Blood Glucose; Blood Pressure; Body Weight; Diabetes Mellitus; Female; Humans; Insulin; Male; Osmolar Concentration; Sodium; Vasopressins; Water-Electrolyte Imbalance

The role of vasopressin in the pathogenesis of partial nephrectomy (PN)-salt hypertension was examined in the rat. Hypertension was produced by reducing renal mass 70% and substituting 1% saline for drinking water 2 to 4 days after surgery. PN alone resulted in an increase in systolic blood pressure. Subsequent salt loading led to a further large increase in arterial pressure. On the second to third day after substitution of saline for drinking water, urinary vasopressin excretion (UADHV) was increased six-fold and the plasma vasopressin concentration was increased two and one-half-fold. UADHV then fell to a level that was three-fold greater than control values 5 days later. Although there was a marked stimulation of vasopressin release during the period of salt loading, a vasopressin pressor antagonist had only a small effect on arterial pressure. This suggests vasopressin is not a major pressor agent in PN-salt hypertension.

Topics: Animals; Blood Pressure; Body Weight; Disease Models, Animal; Hypertension; Male; Nephrectomy; Rats; Sodium Chloride; Vasopressins

In three experiments, the initial body weight losses after estrogenization were maintained or lagged the weight gains of the controls by the same amount over 61, 138, and 336 days, respectively. The mean serum corticosterone level of the controls was 56% that of the estrogenized rats 341 days after estrogenization. Water consumption (mg/kg b.w.) approximated 150% that of the controls several weeks following estrogenization, remaining elevated until the end of the experiment. Estrogen treatment produced a higher level of water intake in a few rats similar to that previously observed for mice. During the experimental period for water measurement, food consumption (g/kg b.w.) approximated 115% that of the controls. Gnawing and food-spilling behavior was observed in some of the estrogenized rats. Following vasopressin administration, food intake was lowered the first and second days in one estrogenized group; water intake was lowered the first day in the three control and estrogenized groups. In contrast to studies with Marsh mice, estrogenization did not produce bladder damage in Evans rats, but two showed tubular calcification in the kidneys.

Topics: Adrenal Glands; Animals; Body Weight; Corticosterone; Drinking; Eating; Estrogens; Housing, Animal; Lung; Male; Organ Size; Rats; Species Specificity; Temperature; Testis; Vasopressins

To examine the weight loss of hyperbaric helium-oxygen habitation, we measured the exchange of liquids and calories in six men who lived in this atmosphere for 32 d. The maximum pressure was 49.5 ATA. The men lost 3.7-10.1 kg, in spite of warm ambient (31-32 degrees C) temperatures and adequate calories (2,737 kcal/d) provided for the sedentary ways of chamber living. Weight loss and a calculated fluid deficit were accompanied by significant hemoconcentration, shown by increases in serum proteins. These changes were followed by a rise in urinary aldosterone and vasopressin, but not thirst. Weight loss in hyperbaric atmospheres is probably multifactorial, but our data suggests an uncoupling of normal osmoregulation may have occurred in the present set of subjects. This may have been due to altered lung mechanics, increased catecholamines, or effects of high pressure on cellular responses to vasopressin.

Topics: Aldosterone; Atmospheric Pressure; Body Weight; Carbon Dioxide; Decompression; Diving; Extraterrestrial Environment; Humans; Oxygen Consumption; Time Factors; Vasopressins; Water-Electrolyte Imbalance

Both dehydration to 87% of original body weight (Wo) and arginine vasotocin (AVT: 20 mU/g) elicited rapid weight gains (ca. 9% of Wo in the 1st h) when terrestrial-phase T. torosa were given access to water. In each case, net weight gain resulted from increased integumental osmosis and antidiuresis. Mesotocin (0.001 -- 0.1 micrograms/g) elicited modest but significant weight gains (ca. 1%/h) caused solely by increased integumental osmosis. Integumental water uptake from wet moss was 66% that of totally immersed animals. Water movement from ventral to dorsal body surface occurred along channels on the skin. Urinary bladder storage capacities in excess of 50% of Wo were observed. Following AVT administration, bladder water resorption increased significantly, while glomerular filtration rate dropped to 16% of control values. The structural and physiological adaptations for water balance in T. torosa are comparable to those found in some terrestrial anurans.

Topics: Animals; Body Water; Body Weight; Dehydration; Glomerular Filtration Rate; Kidney; Prolactin; Salamandridae; Urinary Bladder; Urodela; Vasopressins; Water-Electrolyte Balance

Topics: Adult; Age Factors; Aged; Aging; Aldosterone; Blood Volume; Body Weight; Female; Humans; Kidney; Male; Middle Aged; Potassium; Sex Factors; Vasopressins; Water-Electrolyte Balance

Angiotensin II (AII) was infused into the lateral cerebral ventricle of rats given water, isotonic saline, or hypertonic saline ad libitum, or 40 ml water/day. Fluid intake, change in body weight, plasma [Na+], and plasma and pituitary arginine vasopressin (AVP) levels were measure. Isotonic saline or AII (1 micrograms/microliter saline) was infused at 1 microliter/h for 5 days using osmotic minipumps. AII increased fluid intake of rats given isotonic saline to drink; they consumed an average of 269 +/- 25 ml/day on day 5. AII infusions in rat given water or isotonic saline to drink decreased plasma [Na+] with no changes in plasma or pituitary AVP. However, in rats given hypertonic saline, plasma [Na+] remained at control levels while plasma AVP increased. In water-restricted rats, the effects of AII were intermediate: a small decrease in plasma [Na+] and a small increase in plasma AVP. From these results, it is suggested that although acute AII administration elicits AVP release, this effect diminishes during chronic AII infusion, coincident with reduced plasma [Na+].

Topics: Angiotensin II; Animals; Arginine Vasopressin; Body Weight; Drinking; Male; Pituitary Gland; Rats; Saline Solution, Hypertonic; Sodium; Sodium Chloride; Vasopressins

Body temperatures of exercising humans who have been denied water are elevated when compared to hydrated controls. The simplest "explanation" for the elevated temperature is a decrease in sensitivity of the sweating mechanism. This and similar "explanations" do not direct attention to basic causes but only the result(s) of more fundamental aspects of regulatory physiology. Among the items considered in this speculative presentation are influences of changes in osmolarity, specific ions, peptide hormones, fluid shifts, and muscular contractions during exercise. A hypothesis is offered for consideration in explaining elevations of body temperature in exercise with and without water replacement. In general, the hypothesis relates changes in hypothalamic osmotic pressure and/or ionic constituents with fluid and ionic events in muscle during exercise. The fluid and ionic shifts are probably proportional to the amount of lean body mass engaged in dynamic exercise. Since blood volume has also been shown to be related to lean body mass, similar relative work loads should lead to similar changes in the osmotic and/or ionic environment of the hypothalamus, thus resulting in similar increases in body temperature during exercise. Hypohydration is superimposed on this basic response. Increases in body temperature of resting hypohydrated subjects appear to be due to increases in osmotic pressure and/or specific ion concentrations. During exercise, these changes are added to those induced by muscle contraction. The focal point of all such ionic and osmotic changes is thought to be neural processes within the hypothalamus.

Topics: Body Temperature Regulation; Body Weight; Central Nervous System; Humans; Hypothalamus; Muscle Contraction; Physical Exertion; Prolactin; Sweating; Vasopressins; Water Deprivation; Water Loss, Insensible; Water-Electrolyte Balance

Eighteen healthy male subjects, were investigated under normal sodium intake and after 5 days of high and low sodium intake. Under normal sodium intake, the following mean values were observed -- plasma osmolality (Posm): 294 +/- 5 mOsm/kg -- plasma volume (Vp): 33.9 +/- 4,3 ml/kg -- urinary sodium output (UNa.V): 173 +/- 73 mEq/24 h -- urinary antidiuretic hormone (A.D.H.): 68.8 +/- 35.6 ng/24 h. Under low sodium intake these values decreased to -- Posm: 289 +/- 4 m Osm/kg -- Vp: 32.7 +/- 3.2 ml/kg -- UNa.V: 12 +/- 9 mEq/24 h -- A.D.H.: 40.9 +/- 16.3 ng/24 h. Under high sodium intake these values increased to -- Posm: 298 +/- 5 m Osm/kg -- Vp: 36.3 +/- 4.1 ml/kg -- UNa.V: 325 +/- 67 mEq/24 h -- A.D.H.: 118.2 +/- 45.5 NG/24 H. Highly significant correlations are found between Posm and A.D.H. and between the Posm or A.D.H. and UNa.V. Interest is focused on UNa.V since the correlation between A.D.H. and UNa.V (r = 0.78) is more significant than that between A.D.H. and Posm (r = 0.47). Overriding of Posm on Vp in the regulation of A.D.H. secretion is again demonstrated. Plasma renin activity decrease when A.D.H. increase.

Topics: Adult; Blood Pressure; Body Weight; Creatinine; Humans; Male; Osmolar Concentration; Plasma Volume; Pulse; Renin; Sodium; Vasopressins; Water

Topics: Animals; Body Weight; Brain Mapping; Diuresis; Male; Pituitary Gland, Posterior; Rats; Septal Nuclei; Sodium Chloride; Vasopressins; Water-Electrolyte Balance

Topics: Animals; Antigen-Antibody Reactions; Blood Pressure; Body Weight; Hematocrit; Hypertension; Hypertension, Malignant; Rats; Vasopressins; Water-Electrolyte Balance

A midline stereotaxic lesion in rats destroying the periventricular tissue (lamina terminalis and preoptic-anterior hypothalamic periventricular stratum) surrounding the anteroventral third ventricle (AV3V) produces adipsia without other marked behavioral changes. Although food consumption is reduced in animals rendered adipsic by the lesion, feeding continued and intake is comparable to that of water-deprived-sham-lesioned animals. About half the rats recover drinking after a period of adipsia, but the others never resume water intake and become moribund. An analysis of urinary output indicates that adipsic animals fail to reduce urine volume and continue to elaborate an inappropriately dilute urine. The periventricular lesion-induced adipsia without compensating antidiuresis produces a significant rise in plasma protein, sodium, osmolality, and urea nitrogen which if untreated often results in acute encephalopathy leading to death. These data suggest that preoptic-anterior hypothalamic periventricular tissue houses vital neural elements which function in the modulation of water ingestive and conservation mechanisms directed at the maintenance of body fluid homeostasis.

Topics: Animals; Behavior, Animal; Body Weight; Brain; Cerebral Ventricles; Drinking Behavior; Eating; Hypothalamus; Kidney; Male; Osmolar Concentration; Preoptic Area; Rats; Thirst; Urine; Vasopressins

The reasons for the decrease of intraocular pressure after drinking of alcohol were examined. The dose of alcohol was 2 ml 38% Weinbrand per kg body weight, which corresponds to 53 ml pure alcohol for a person of 70 kg body weight. The tonographic data gave no correlation between the blood-alcohol level and the changes of intraocular pressure. The antidiuretic hormon also had no correlation to the intraocular pressure changes. Tonometry with the same frequency as in this study but without alcohol showed no alteration of intraocular pressure. It is suggested that alcohol acts probably by a decrease of secretion of aqueous humour by central actions.

Topics: Alcohol Drinking; Aqueous Humor; Body Weight; Ethanol; Humans; Intraocular Pressure; Tonometry, Ocular; Vasopressins

Because vasopressin is one of the most potent naturally occurring pressor agents, and because of its importance in the regulation of blood volume and composition, we have undertaken a study of the role of vasopressin in the pathogenesis of the hypertension in the Okamoto-Aoki spontaneously hypertension (SH) rat. In SH rats, systolic blood pressure increased from 135 +/- 3 (SE) mmHg at age 33 days to 184 +/- 3 mmHg at age 75 days (P less than 0.01). In the Wistar-Kyoto (WKY) control rats, blood pressure increased from 100 +/- 2 to 120 +/- 2 mmHg (P less than 0.01). The differences in blood pressure between the SH and WKY rats at all ages were significant (P less than 0.01). During the age period 33-75 days, the 24-h urinary excretion of vasopressin in the SH rat was consistently more than twofold greater (P less than 0.01) than in the WKY rat. Plasma vasopressin concentration and pituitary vasopressin content were also elevated in the SH rat (P less than 0.01 and P less than 0.02, respectively). Changes in systolic blood pressure in the SH rat, however, were not paralleled by changes in the urinary excretion of vasopressin. The data indicate that the secretion of vasopressin is elevated in the SH rat. However, the magnitude of this elevation, in and of itself, may not be sufficient to account for the rising blood pressure in the young SH rat.

Topics: Animals; Body Weight; Hypertension; Male; Pituitary Gland, Posterior; Radioimmunoassay; Rats; Time Factors; Vasopressins

In the present study, the effect of selective glucocorticoid deficiency on renal water excretion was investigated in conscious, trained, adrenalectomized dogs. The animals were studied before and after a water load while on replacement therapy of desoxycorticosterone acetate, 5 mg/day, and dexamethasone, 0.8 mg/day (group I), and while off dexamethasone for 5-9 days (group II). Before the water load the weight, inulin space, cardiac output, blood pressure, glomerular filtration rate, renal blood flow, plasma osmolality, and plasma antidiuretic hormone measured by radioimmunoassay were similar in both groups I and II. However, after a 40 ml/kg water load a marked impairment in renal water excretion in the glucocorticoid deficient dogs became apparent. Maximal free water clearance was -0.046+/-0.16 vs. 6.51+/-0.72 ml/min (P < 0.001) and minimal urinary osmolality was 425+/-56 vs. 82+/-3.5 mosmol/kg H(2)O (P < 0.001) in group II as compared to group I. Plasma antidiuretic hormone was maximally suppressed during the water load in group I to 0.34+/-0.08 pg/ml but remained elevated at 9.18+/-1.79 pg/ml (P < 0.005) in group II. This nonsuppressibility of plasma antidiuretic hormone during water loading in group II was associated with a significant tachycardia of 145+/-6 vs. 87+/-6 beats/min (P < 0.001) in group I and a significantly lower stroke volume of 27+/-0 vs. 59+/-0.5 ml/beat (P < 0.001). In conclusion, our results implicate a persistent secretion of antidiuretic hormone as an important factor in the impaired water excretion of glucocorticoid deficiency. A deleterious effect of glucocorticoid deficiency on cardiac function was observed and this hemodynamic alteration could be involved in initiating a nonosmolar, baroreceptor-mediated release of vasopressin.

Topics: Adrenalectomy; Animals; Blood Pressure; Body Weight; Cardiac Output; Dogs; Glomerular Filtration Rate; Glucocorticoids; Kidney; Osmolar Concentration; Vascular Resistance; Vasopressins; Water Intoxication; Water-Electrolyte Balance

The stimulating effect of different pituitary hormones on longitudinal bone growth was determined with tetracycline as intravital marker in hypophysectomized rats. Growth hormone was found to be the most effective growth stimulating pituitary hormone. At considerably higher doses, thyrotrophic hormone (TSH) and prolactin also showed growth stimulating pituitary hormone. At considerably higher doses, thyrotrophic hormone (TSH) and prolactin also showed growth stimulating activity. TSH exerts its effect via the production of thyroxine, whereas the growth stimulation by prolactin seems to be a direct effect of this hormone, similar to the effect of growth hormone. The LH, FSH, ACTH, MSH, vasopressin and oxytocin preparations did not stimulate longitudinal bone growth.

Topics: Adrenocorticotropic Hormone; Animals; Body Weight; Bone Development; Cartilage; Drug Synergism; Female; Follicle Stimulating Hormone; Growth Hormone; Hypophysectomy; Luteinizing Hormone; Melanocyte-Stimulating Hormones; Oxytocin; Pituitary Hormones; Prolactin; Rats; Stimulation, Chemical; Thyrotropin; Thyroxine; Tibia; Vasopressins

The rate of cutaneous water uptake after dehydration was significantly depressed in functionally neurohypophysectomized toads (Bufo marinus), which consequently regained weight much more slowly than intact toads when returned to water. Toads bearing hypothalamic lesions were able to develop an antidiuresis when removed from water to a saturated atmosphere, but the antidiuresis was solely glmerular in origin and was established more slowly than in intact animals. The fractional reabsorption of filtrate increased significantly and the relative free water clearance decreased significantly in intact toads after removal from water. These changes in tubular function, which were not seen in lesioned toads, were responsible for the development of a more rapid and effective antidiuresis in intact animals. Injections of iso-osmotic saline, oxytocin (250 mu./100 g) and vasopressin (50 mu./100 g) had no significant effect on rates of cutaneous water uptake in both intact and lesioned toads. Injections of hyperosmotic saline, however, significantly increased rates of water uptake in both groups of toads, but to a much greater extent in the intact animals. Fluid retention arising from a marked antidiuresis occurred after the injection of vasopressin and hyperosmotic saline, and there was some evidence of an antidiuretic effect of oxytocin with the doses used here. These results and their bearing on the question of the functional significance of the neurohypophysis in anuran amphibians are discussed.

Topics: Animals; Body Water; Body Weight; Bufo marinus; Desiccation; Diuresis; Hypothalamus; Inulin; Kidney; Vasopressins

1 The effect of a combination of chloropropamide and chlorothiazide in Brattleboro rats with hereditary hypothalamic diabetes insipidus (DI) treated with low doses of vasopressin (Pitressin tannate in oil) was investigated with particular reference to the time course of response from the initiation of treatment. 2 Analysis of the relationship between water intake and body weight indicated no real correlation and body weight accounted for only 4.4% of the variation in water intake. It was therefore decided to use whole body responses as the index in preference to the response per unit body weight. 3 The daily administration of 5 mg chlorpropamide combined with chlorothiazide in the drinking water (4 mg/1) to Pitressin-treated DI rats potentiated the response to small doses of vasopressin (25 and 50 mu Pitressin/24 hours). Water intake was reduced by the drug combination by an average of 12.35 ml/24 h, but only on the second day of treatment was the decrease of any real magnitude (30 ml/24 h but otherwise 9 ml/24 h or less). Analysis of urine volume measurements gave similar results to those obtained for water intake and the potency ratio measured in terms of free water clearance was 1.26 (agreeing closely with the ratio for water intake which was 1.24). 4 A reduction in the solute excretion was observed only in those DI rats treated with the higher dose of Pitressin (50 mu/24 h) combined with the two drugs. 5 Possible reasons for the discrepancy between the effect of the combination of chlorpropamide and chlorathiazide on water metabolism in the DI rat and the DI patient are discussed.

Topics: Animals; Body Weight; Chlorothiazide; Chlorpropamide; Diabetes Insipidus; Drinking; Female; Hypothalamus; Kinetics; Osmolar Concentration; Rats; Urine; Vasopressins

During the onset of malignant hypertension (MH) in rats treated with deoxycorticosterone trimethylacetate (DOC), plasma arginine vasopressin (AVP) concentrations increase tenfold as a consequence of hypovolemia and hyperosmolality. In benign hypertensive (BH) rats, plasma AVP is increased threefold in comparison with control animals. Plasma renin is markedly suppressed in both BH and MH animals. In MH rats, biologically active AVP antiserum lowers blood pressure (BP) transiently to normal or subnormal levels; in BH rats, a small BP-lowering effect of the AVP antiserum is seen. (Biologically active angiotensin II antiserum does not lower BP in MH rats.) The relationship between the height of BP and plasma AVP concentration in DOC hypertensive rats indicates, when compared with that relationship in diabetes insipidus rats infused with AVP, a marked enhancement of the vasopressor effect of AVP. These findings and the earlier observation of vasopressin-induced vascular damage by Byrom (F. B. Byrom, The Hypertensive Vascular Crisis. London: Heinemann, 1969) strongly suggest that ADH is involved as a vasopressor hormone in the pathogenesis of malignant DOC hypertension.

Topics: Angiotensin II; Animals; Antibodies; Arginine Vasopressin; Blood Pressure; Body Weight; Desoxycorticosterone; Diabetes Insipidus; Hypertension; Hypertension, Malignant; Immune Sera; Male; Nephrectomy; Osmolar Concentration; Rats; Renin; Sodium; Urea; Vasomotor System; Vasopressins

Topics: Animals; Arginine Vasopressin; Body Weight; Dehydration; Glomerular Filtration Rate; Inulin; Kinetics; Osmolar Concentration; Pituitary Gland, Posterior; Salamandridae; Skin; Skin Physiological Phenomena; Sodium Chloride; Sucrose; Urinary Bladder; Urodela; Vasopressins; Water-Electrolyte Balance

Rats homozygous for the mutant gene for diabetes insipidus (Brattleboro strain) are stunted in growth compared to rats heterozygous for the mutant gene and normal rats without the mutant gene. The hypothesis was tested that normal growth depends upon the presence of vasopressin. It was expected that replacement therapy of vasopressin rats homozygous for diabetes insipidus would make possible a normal growth rate similar to that of rats heterozygous for diabetes insipidus. Rats heterozygous and homozygous for diabetes insipidus were treated with 0.25 U (Days 0-9) and 0.5 U (Days 10-29) of vasopressin during the first month of life. During the treatment period, vasopressin significantly increased the urine osmolatities of the homozygous rats demonstrating the renal effectiveness of the vasopressin. The results showed that remedial vasopressin administration could not produce normal growth rates in homozygous rats and may be detrimental. Six weeks following vasopressin treatment, homozygous, diabetes insipidus rats which had received vasopressin had increased 24 hr water intakes and decreased urine osmolalities compared to control, homozygous rats, Heterozygous rats also had decreased urine osmolalities resulting from vasopressin six weeks after the cessation of vasopressin treatment.

Topics: Aging; Animals; Body Height; Body Weight; Diabetes Insipidus; Drinking; Female; Genotype; Growth; Hypothalamus; Male; Osmolar Concentration; Rats; Vasopressins; Water

Topics: Blood Volume; Body Weight; Cystic Fibrosis; Humans; Hyponatremia; Vasopressins

Plasma vasopressin (VP) was determined in 28 patients with chronic renal failure undergoing hemodialysis. Plasma VP levels were significantly higher in the patients than in the normal subjects. It was also observed that plasma VP levels did not fall significantly despite a marked decrease of effective plasma osmolality following hemodialysis, and that no correlation was obtained between the plasma VP levels and effective plasma osmolality, both before and after hemodialysis. By analyzing the changes in blood volume and blood pressure in addition to plasma osmolality in each case, a dysfunction of VP release in response to osmotic stimulus was found in 5 out of 28 patients.

Topics: Adolescent; Adult; Blood Pressure; Blood Volume; Body Weight; Female; Humans; Kidney Failure, Chronic; Male; Middle Aged; Osmolar Concentration; Renal Dialysis; Vasopressins

Negative sodium balance was produced in 10 human volunteers. Body weight, plasma sodium, osmolality, hematocrit, renin activity (PRA), and antidiuretic hormone (ADH) concentrations were determined before, during, and after sodium restriction. Body weight declined and PRA rose during the period of low sodium intake. Plasma sodium concentration and osmolality did not change. A statistically significant change in ADH was not observed. It is suggested that a decrease in ADH was prevented by a rising titer of renin and contraction of the extracellular space.

Topics: Body Weight; Diet; Extracellular Space; Female; Hematocrit; Humans; Male; Renin; Sodium Chloride; Vasopressins

Topics: Adrenalectomy; Animals; Body Weight; Calcium; Chlorides; Diabetes Insipidus; Drinking Behavior; Magnesium; Male; Potassium; Rats; Sodium; Urea; Vasopressins; Water-Electrolyte Imbalance

Topics: Anesthetics; Animals; Biological Transport; Biological Transport, Active; Blood; Body Water; Body Weight; Rana pipiens; Regression Analysis; Sodium Chloride; Urinary Bladder; Vasopressins

Rats with unilateral nephrectomy were offered 1% sodium chloride as drinking fluid and were injected with desoxycorticosterone trimethylacetate (D.O.C.-T.M.A.) at weekly intervals. During the fourth to seventh week after the start of the experiment, malignant hypertension developed in most of the animals: body weight fell, reflecting volume depletion; serum osmolality and serum sodium and urea concentrations increased; in the kidneys malignant nephrosclerosis occurred. In such animals, plasma concentrations of arginine-vasopressin were increased ten-fold in comparison with control animals; intravenous injection of a specific vasopressin antibody resulted in a transient fall of blood-pressure (B.P.) to normal or subnormal levels, while the injection of an angiotensin-I or angiotensin-II antibody did not affect B.P. In control animals none of the antibodies had an effect on B.P. It is concluded that in the pathogenesis of malignant D.O.C. hypertension vasopressin plays a role similar to that of renin-angiotensin in malignant renal hypertension.

Topics: Angiotensin II; Animals; Antibodies; Arginine Vasopressin; Blood Pressure; Body Weight; Desoxycorticosterone; Eating; Hypertension, Malignant; Male; Osmolar Concentration; Rats; Rats, Inbred Strains; Sodium; Urea; Vasopressins

This study conducted on the crewmembers of Skylab 3 was designed to evaluate the endocrinological adaption resulting from extend exposure to a space flight environment by identifying changes in hormonal and associated fluid and electrolyte parameters. The three men served as their own controls and were on a constant dietary intake. Complete metabolic collections were performed beginning 21 d before the flight, continuing throughout the flight, for 18 d postflight. Changes in fluid and electrolyte balance have been correlated with weight loss, changes in the excretion of aldosterone, vasopressin, and fluid compartments. Inter-individual variability was demonstrated in most experimental indices measured; however, statistically significant patterns have emerged which include: decreases in body weight and ADH, increases in plasma renin activity, and elevations in urinary catecholamines, aldosterone and cortisol concentrations. Urinary sodium was increased in flight but potassium was only slightly changed. Total body exchangeable K was slightly decreased in all three of the crewmen. Total body water and extracellular fluid were decreased postflight in almost all cases. The measured changes are consistent with the prediction that a relative increase in thoracic blood volume upon transiton to the zero gravity environment is interpretated as a true volume expasion resulting in a net fluid loss. This, in association with other factors, ultimately results in a reduction in intravascular volume leading to an increase in renin and a secondary aldosteronism. Once these compensatory mechanisms are effective in reestablishing positive water balance, the crewemn are considered to be essentially adapted to the space environment. Although the physiological cost of this adaptation must reflect the electrolyte deficit and perhaps other factors, it is assumed that the compensated state is adequate for the demands of the environment; however, this new homeostatic set is not believed to be without physiological cost and could, except with proper precautions, reduce the functional reserve of exposed individuals.

Topics: Adrenocorticotropic Hormone; Adult; Aldosterone; Blood Volume; Body Water; Body Weight; Catecholamines; Endocrine Glands; Humans; Hydrocortisone; Male; Potassium; Renin; Sodium; Space Flight; Vasopressins; Water-Electrolyte Balance; Weightlessness

Lyophilized bovine, porcine, and human choroid plexuses contain .02-.09 U of antidiuretic activity per milligram. The antidiuretic factor in bovine choroid plexus was concentrated 100 times by extraction with acetic acid, fractional precipitation with acetone and ethyl ether, gel filtration, and paper chromatography. Resulting choroid plexus fraction IIgammaB2 was eluted from Sephadex G-25 in position corresponding to molecular weight between 750 and 3,500; its antidiuretic activity was destroyed by trypsin, performic acid, and thioglycollic acid, but was not affected by leucine aminopeptidase, carboxypeptidase A or B, or cyanogen bromide. HgammaB2 possesses antidiuretic, pressor, and oxytocic potencies (measured in anesthetized-hydrated rat, anesthetized rat, and isolated rat uterus, respectively) of 1.9, 0.5, and 0.1 U/mg, respectively.

Topics: Aminopeptidases; Animals; Biological Assay; Body Weight; Bufo marinus; Carboxypeptidases; Cattle; Choroid Plexus; Cyanogen Bromide; Dogs; Formates; Haplorhini; Humans; Lipid Metabolism; Oxytocin; Pituitary Gland; Rats; Swine; Thioglycolates; Trypsin; Vasopressins

Topics: Analgesia; Animals; Arginine Vasopressin; Body Temperature; Body Weight; Drug Synergism; Female; Humans; Morphine Dependence; Naloxone; Oligopeptides; Oxytocin; Rats; Structure-Activity Relationship; Vasopressins

Topics: Aged; Body Weight; Diuretics; Humans; Hypertension; Hyponatremia; Polythiazide; Potassium; Potassium Chloride; Potassium Deficiency; Sodium; Vasopressins; Water-Electrolyte Balance

Oral carbamazepine has been shown to have antidiuretic activity in seven out of nine patients with neurohypophyseal diabetes insipidus. At the doses used side-effects were not a major problem. In the eighth patient a carbamazepine and clofibrate combination was effective but in the ninth carbamazepine was without effect. It is suggested that carbamazepine should be used initially in neurohypophyseal diabetes insipidus if oral therapy is indicated, but the mode of its antidiuretic action is as yet unclear.

Topics: Adolescent; Adult; Arginine Vasopressin; Body Water; Body Weight; Carbamazepine; Diabetes Insipidus; Diuresis; Drinking; Drug Synergism; Drug Therapy, Combination; Female; Humans; Male; Middle Aged; Osmolar Concentration; Vasopressins

Lithium (Li+) chloride, 2 to 3 mEq. per kilogram of body weight, was administered intraperitoneally to normal Wistar rats daily for 4 to 66 days. This resulted in a marked reduction in urine osmolality (Uosm.) and increase in the excretion of water, Na+, K+, uric acid, and phosphate. The excretion of uric acid and potassium was a direct function of UNaV. The magnitude of depression in urine osmolality was significantly related to the rate of excretion of lithium in the urine, suggesting that the change in water reabsorption is dependent on the presence of the ion in the luminal side of the tubule. During 2 per cent saline diuresis, Li+-treated rats achieved less fractional free water reabsorption (TcH2O/GFR times 100) at any level of fractional osmolar clearance (Cosm./GFR times 100) than normal rats. On the other hand, during 0.225 per cent saline diuresis, fractional free water clearance (CH2O/GFR times 100) was normal over a wide range of fractional urine flow (V/GFR times 100), indicating intact function of the ascending limb of the loop of Henle. The intravenous infusion of vasopressin (VP) or dibutyryl cyclic-adenosine monophosphate (dcAMP) to Li+-treated rats resulted in a modest rise in Uosm. and a reduction in V/GFR times 100 and CH2O/GFR times 100. Although the response to VP appeared earlier than that to dibutyryl cyclic-AMP, the magnitude of the changes in Uosm., V/GFR times 100, and CH2O/GFR times 100 was eventually the same with both substances. Comparison between normal and Li+-treated rats revealed that the response to both VP and dibutyryl cyclic-AMP was blunted, albeit to a greater extent in the former. Inhibition by Li+ of adenylate cyclase will only partially explain the present data. Impairment in the release of endogenous VP or a block distal to the formation of cyclic-AMP must have played a role. In view of a normal diluting capacity and the increase in the excretion of phosphate and uric acid, it is suggested that Li+, when administered chronically in the present doses, inhibits proximal tubular reabsorption.

Topics: Animals; Body Weight; Bucladesine; Dehydration; Female; Kidney; Kidney Concentrating Ability; Kidney Tubules, Distal; Kidney Tubules, Proximal; Lithium; Male; Phosphates; Potassium; Rats; Sodium; Uric Acid; Vasopressins; Water-Electrolyte Balance

The renal tubular responsiveness to antidiuretic hormone was assessed in seven obese patients during starvation and feeding by an overnight dehydration test followed by exogenous vasopressin. All seven subjects showed a mean reduction of one-third in their maximum urinary osmolality on day 4 of starvation. Thes- data show that the renal tubule is partially insensitive to antidiuretic hormone at a time when it is also insensitive to mineralocorticoids.?Author

Topics: Adult; Body Weight; Dehydration; Diet; Fasting; Humans; Kidney Tubules; Middle Aged; Mineralocorticoids; Nutritional Physiological Phenomena; Obesity; Osmolar Concentration; Time Factors; Urination; Urine; Vasopressins

Topics: Animals; Avoidance Learning; Body Weight; Conditioning, Operant; Corticosterone; Diabetes Insipidus; Electroshock; Exploratory Behavior; Heterozygote; Homozygote; Male; Memory; Motor Activity; Organ Size; Pituitary-Adrenal System; Rats; Testis; Vasopressins

Since previous studies from this laboratory have demonstrated that the redistribution of blood volume and concomitant relative central hypervolemia induced by water immersion to the neck causes a profound natriuresis and a suppression of the renin-aldosterone system, it was of interest to assess whether the diuresis induced by immersion was mediated by an analogous inhibition of ADH. The effects of water immersion on renal water handling and urinary ADH excretion were assessed in 10 normal male subjects studied following 14 h of overnight dehydration on two occasions, control and immersion. The conditions of seated posture and time of day were identical. During control ADH persisted at or above prestudy values. Immersion resulted in a progressive decrease in ADH excretion from 80.1 plus or minus 7 (SEM) to 37.3 plus or minus 6.3 muU/min (P smaller than 0.025). Cessation of immersion was associated with a marked increase in ADH from 37.3 +/- 6.3 muU/min to 176.6 +/- 72.6 muU/min during the recovery hour (P smaller than 0.05). Concomitant with these changes urine osmolality decreased significantly beginning as early as the initial hour of immersion from 1044 +/- 36 to 542 +/- 66 mosmol/kg H2O during the final hour of immersion (P smaller than 0.001). Recovery was associated with a significant mean increase in Uosm of 190 +/- 40 mosmol/kg H2O over the final hour of immersion (P smaller than 0.001). The suppression of ADH occurred without concomitant changes in plasma tonicity. These studies are consistent with the suggestion that in hydrated subjects undergoing immersion suppression of ADH release contributes to the enhanced free water clearance, which has been previously documented.

Topics: Adult; Blood Volume; Body Weight; Creatinine; Dehydration; Diuresis; Humans; Immersion; Male; Osmolar Concentration; Potassium; Sodium; Time Factors; Urine; Vasopressins

A patient with Ewing's sarcoma presented with the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) (1). Plasma values for vasopressin were found to be over four times the normal values expected for the plasma osmolality. At postmortem examination, the arginine vasopressin concentration in the tumor tissue was ten times that of the plasma. These data suggest that Ewing's sarcoma may cause SIADH.

Topics: Adolescent; Arginine Vasopressin; Blood; Body Weight; Humans; Male; Osmolar Concentration; Pituitary Diseases; Pituitary Gland, Posterior; Sarcoma, Ewing; Urine; Vasopressins

1. In order to study the effect of overhydration on body potassium, experiments were performed on pair-fed rabbits, one of which was maintained continuously on vasopressin and given extra water (60-90 ml day-1 kg-1) for 6-8 days, while the other served as control. 2. Overhydrated rabbits excreted significantly more potassium (53%) in their urine than control rabbits and accumulated a mean potassium deficit of 65-0 mmol, significantly higher than the mean value of 37-1 mmol in the control rabbits. 3. In the overhydrated rabbits, potassium fell significantly in both erythrocytes, from 266 to 173 mmol/kg of dry cells, and also in muscle, from 435 to 341 mmol/kg of fat-free dry solids. Neither changed significantly in the control animals. 4. Overhydration in the presence of vasopressin leads to potassium depletion in the rabbit and a similar phenomenon might be expected in man. Potassium depletion due to overhydration might account for the hypokalaemia and reduction in exchangeable potassium observed in some patients with the syndrome of inappropriate secretion of antidiuretic hormone.

Topics: Animals; Body Weight; Erythrocytes; Hypokalemia; Muscles; Osmolar Concentration; Potassium; Rabbits; Sodium; Urine; Vasopressins; Water Intoxication; Water-Electrolyte Balance

Topics: Age Factors; Animals; Aorta, Thoracic; Barium Sulfate; Blood Pressure; Body Water; Body Weight; Cardiomegaly; Constriction; Dose-Response Relationship, Drug; Heart Ventricles; Hypertension, Renal; Kidney; Male; Muscle, Smooth; Norepinephrine; Organ Size; Renal Artery; Time Factors; Vasopressins

Topics: Adrenal Glands; Animals; Body Weight; Dehydration; Diabetes Insipidus; Drinking; Drug Resistance; Eating; Female; Kidney Glomerulus; Kidney Medulla; Kinetics; Male; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Inbred Strains; Osmolar Concentration; Sodium Chloride; Vasopressins; Water; Water Deprivation

Topics: Administration, Oral; Adolescent; Adult; Arginine; Body Weight; Carbamazepine; Creatine; Diabetes Insipidus; Female; Hemoglobins; Humans; Kidney Tubules, Distal; Male; Middle Aged; Osmosis; Potassium; Radioimmunoassay; Sodium; Urination; Vasopressins; Water

Topics: Animals; Body Weight; Dehydration; Drinking Behavior; Environment, Controlled; Environmental Exposure; Feeding Behavior; Hypothermia; Hypoxia; Kidney; Kidney Concentrating Ability; Male; Organ Size; Osmolar Concentration; Oxygen Consumption; Rats; Regression Analysis; Time Factors; Urination; Vasopressins; Water

Topics: Animals; Body Weight; Diabetes Insipidus; Diuresis; Dose-Response Relationship, Drug; Drinking; Hematocrit; Heterozygote; Homozygote; Male; Osmolar Concentration; Plasma Volume; Potassium; Rats; Sodium; Urine; Vasopressins; Water-Electrolyte Balance

Topics: Body Weight; Chemical Phenomena; Chemistry; Humans; Hyponatremia; Male; Middle Aged; Natriuresis; Osmolar Concentration; Schizophrenia; Syndrome; Thiothixene; Vasopressins; Water

Topics: Animals; Biological Assay; Blood Pressure; Body Weight; Chromatography, Gel; Diabetes Insipidus; Freund's Adjuvant; Heterozygote; Homozygote; Iodine Radioisotopes; Male; Pituitary Gland, Posterior; Radioimmunoassay; Rats; Rodent Diseases; Tissue Extracts; Vasopressins

Topics: Animals; Aorta, Thoracic; Barium; Blood Pressure; Blood Vessels; Body Weight; Chlorides; Dose-Response Relationship, Drug; Female; Heart Rate; Heart Ventricles; Hemodynamics; Hypertension; Hypertension, Renal; Kidney; Male; Muscle, Smooth; Norepinephrine; Organ Size; Rats; Regional Blood Flow; Stimulation, Chemical; Vascular Resistance; Vasopressins

Topics: Adolescent; Adult; Amino Acids; Body Weight; Calcium; Cyclophosphamide; Cystitis; Diuresis; Female; Glomerular Filtration Rate; Humans; Hyponatremia; Kidney; Kidney Concentrating Ability; Male; Middle Aged; Natriuresis; Neoplasms; Osmolar Concentration; Phosphorus; Potassium; Proteinuria; Uric Acid; Vasopressins

Topics: Animals; Body Weight; Dehydration; Female; Gerbillinae; Humidity; Hypothalamo-Hypophyseal System; Kidney; Male; Vasopressins

Topics: Adult; Body Fluids; Body Weight; Creatinine; Dehydration; Glomerular Filtration Rate; Humans; Kidney Concentrating Ability; Male; Osmolar Concentration; Physical Exertion; Potassium; Sodium; Steam Bath; Temperature; Vasopressins

Topics: Animals; Body Weight; Diabetes Insipidus; Diet; Drinking; Lithium; Male; Osmolar Concentration; Photometry; Polyuria; Rats; Sodium; Time Factors; Urination; Vasopressins

Topics: Adrenal Glands; Animals; Blood Pressure; Body Weight; Desoxycorticosterone; Electrophoresis, Disc; Female; Ganglia, Autonomic; Hypertension; Myocardium; Norepinephrine; Organ Size; Pentolinium Tartrate; Pituitary Gland; Rats; Rats, Inbred Strains; Sound; Spleen; Thymus Gland; Time Factors; Tyramine; Vasopressins

Topics: Adaptation, Physiological; Adaptation, Psychological; Air Microbiology; Aldosterone; Arrhythmias, Cardiac; Bacteria; Blood Pressure; Blood Volume; Body Weight; Defecation; Eating; Ecological Systems, Closed; Exercise Therapy; Female; Food; Fungi; Group Structure; Heart Rate; Humans; Hygiene; Male; Minerals; Musculoskeletal System; Potassium; Protective Clothing; Radiation Effects; Recreation; Sensory Deprivation; Sleep; Social Isolation; Space Flight; Time Factors; United States; USSR; Vasopressins; Vestibule, Labyrinth; Water-Electrolyte Balance; Weightlessness

Topics: Adrenal Glands; Angiotensin II; Animals; Body Weight; Female; Hippocampus; Hypertension; Kidney; Noise; Norepinephrine; Organ Size; Pituitary Gland; Rats; Rats, Inbred Strains; Septal Nuclei; Septum Pellucidum; Thyroid Gland; Tyramine; Vasopressins

Topics: Adult; Body Water; Body Weight; Diuresis; Epilepsy, Tonic-Clonic; Female; Furosemide; Humans; Hypertonic Solutions; Hyponatremia; Injections, Intravenous; Male; Osmolar Concentration; Potassium; Potassium Chloride; Sodium; Sodium Chloride; Syndrome; Urine; Vasopressins

Topics: Adrenal Glands; Adrenocorticotropic Hormone; Animals; Body Weight; Corticosterone; Cortisone; Desoxycorticosterone; Estradiol; Female; Gonads; Growth Hormone; Male; Oxygen Consumption; Oxytocin; Pancreas; Parathyroid Glands; Pineal Gland; Pituitary Gland; Progesterone; Prolactin; Rats; Testosterone; Thymus Gland; Thyroid Gland; Thyroxine; Triiodothyronine; Vasopressins

Topics: Angiotensin II; Animals; Body Weight; Diabetes Insipidus; Feedback; Hematocrit; Heterozygote; Male; Radioimmunoassay; Rats; Sodium; Time Factors; Vasopressins; Water-Electrolyte Balance

1. The capacity of adaptation of toads (Bufo bufo) to environments of high salinity was studied and the relative importance of skin, kidney and urinary bladder in controlling the balance of water and salt was assessed.2. Toads were kept in NaCl solutions of 20, 50, 110, 150 and 220 mM and studied in their fourth week of adaptation. A group of animals considered as ;control' was kept in wet soil with free access to water. Plasma, ureter urine, and bladder and colon contents were analysed for sodium, potassium, chloride and osmolality, and total body sodium and water were determined. Absorption of water and (22)Na through the skin, and water flow and sodium excretion through the ureter, of intact animals was studied. Hydrosmotic water transport through the isolated urinary bladder of ;control' and adapted animals was determined. The effects of pitressin and aldosterone on the water and sodium balance are described.3. The survival rates of toads kept in saline concentrations up to 150 mM were identical to that of ;control' animals, but half of the animals kept in 220 mM died within 4 weeks.4. There is a linear correlation between the sodium concentrations and osmolality of plasma and of the external media.5. The sodium concentration in colon contents rose with rising external concentrations, up to values higher than the values in plasma.6. Sodium concentrations and osmolalities of ureter and bladder urine increased in adapted animals, the values for bladder urine becoming much higher than those for ureter urine in animals adapted to 110, 150 and 220 mM.7. Total body water, as a percentage of total weight was kept within very narrow limits, although the total body sodium increased with adaptation.8. Absorption of water through the skin for the same osmotic gradients was smaller in adapted than in ;control' animals.9. The ureteral output of water of toads adapted to 110 and 150 mM-NaCl was larger than the water absorption through the skin.10. Skin absorption of sodium was lower in animals adapted to concentrated saline solutions than in ;control' animals.11. Sodium output by the ureter was identical to skin absorption in ;control' animals adapted to 20, 50 and 110 mM-NaCl but was higher in animals adapted to 150 mM-NaCl.12. Aldosterone increased the absorption of sodium in ;control' and adapted toads, but at all dose levels absorption by control was greater than by adapted animals.13. The stimulation of water absorption by vasopressin in vivo or in isolated bl

Topics: Adaptation, Physiological; Aldosterone; Animals; Body Weight; Bufo bufo; Chlorides; Colon; Kidney; Osmolar Concentration; Potassium; Skin Absorption; Sodium; Sodium Isotopes; Ureter; Urinary Bladder; Vasopressins; Water-Electrolyte Balance

Topics: Animals; Body Weight; Cats; Dehydration; Disease Models, Animal; Hypernatremia; Hypothalamus; Natriuresis; Osmolar Concentration; Potassium; Silver Nitrate; Vasopressins; Water-Electrolyte Balance

Topics: Acute Kidney Injury; Adolescent; Adult; Aged; Anuria; Body Weight; Child; Child, Preschool; Creatinine; Diuresis; Female; Glomerular Filtration Rate; Humans; Kidney Concentrating Ability; Male; Middle Aged; Natriuresis; Nephrons; Osmolar Concentration; Vasopressins; Water-Electrolyte Balance

Topics: Anesthesia, Inhalation; Blood Urea Nitrogen; Body Weight; Creatinine; Drug Synergism; Fluorides; Gentamicins; Humans; Kidney Diseases; Male; Methoxyflurane; Middle Aged; Osmolar Concentration; Postoperative Complications; Uric Acid; Urine; Vasopressins; Water-Electrolyte Balance

Topics: Adult; Aldosterone; Aminohippuric Acids; Body Weight; Calcium; Diuresis; Female; Humans; Hydrotherapy; Inulin; Muscle Cramp; Parathyroid Hormone; Posture; Potassium; Renin; Self Medication; Sodium; Tetany; Time Factors; Vasopressins; Water; Water-Electrolyte Balance

Topics: Body Fluids; Body Weight; Central Venous Pressure; Extracellular Space; Humans; Hypernatremia; Hyponatremia; Kidney; Osmolar Concentration; Osmotic Pressure; Sodium; Surgical Procedures, Operative; Tongue, Fissured; Vasopressins; Water Deprivation; Water-Electrolyte Balance

Topics: Age Factors; Animals; Body Weight; Bone Development; Diabetes Insipidus; Female; Genetic Diseases, Inborn; Growth; Growth Hormone; Male; Osmolar Concentration; Rats; Sex Factors; Tail; Urine; Vasopressins; Water

Topics: Age Factors; Animal Nutritional Physiological Phenomena; Animals; Body Weight; Caseins; Dietary Proteins; Diuresis; Female; Glomerular Filtration Rate; Kidney; Kidney Function Tests; Kidney Tubules; Nephrons; Pregnancy; Pregnancy Complications; Protein Deficiency; Rats; Secretory Rate; Vasopressins

Topics: Aerospace Medicine; Body Fluids; Body Weight; Conjunctiva; Dehydration; Diuresis; Environment; Humans; Humidity; Lip; Male; Mucous Membrane; Nasal Mucosa; Pharynx; Temperature; Time Factors; Vasopressins; Water-Electrolyte Balance

Topics: Adaptation, Physiological; Animals; Blood Volume; Body Weight; Chlorides; Drinking; Food Deprivation; Gerbillinae; Hematocrit; Kidney Concentrating Ability; Male; Osmolar Concentration; Potassium; Rats; Sodium; Species Specificity; Urination; Vasopressins; Water; Water-Electrolyte Balance

Topics: Adolescent; Adult; Animals; Biological Assay; Body Weight; Electroconvulsive Therapy; Humans; Male; Rats; Schizophrenia; Vasopressins

Topics: Adolescent; Adult; Anxiety Disorders; Body Weight; Chlorpromazine; Electroconvulsive Therapy; Humans; Male; Schizophrenia; Stimulation, Chemical; Vasopressins

Topics: Animal Nutritional Physiological Phenomena; Animals; Blood; Blood Glucose; Body Water; Body Weight; Chlorides; Craniocerebral Trauma; Hematocrit; Hypothalamus; Male; Osmolar Concentration; Pituitary Gland; Pituitary Gland, Posterior; Potassium; Rats; Sodium; Time Factors; Vasopressins

Topics: Adrenocorticotropic Hormone; Animals; Biological Assay; Body Weight; Chromatography, Ion Exchange; Diabetes Insipidus; Drug Contamination; Drug Synergism; Female; Growth Hormone; Humans; Hyponatremia; Middle Aged; Rats; Swine; Vasopressins; Water Intoxication

Topics: Adolescent; Adrenocorticotropic Hormone; Adult; Anthropometry; Arginine; Arm; Body Height; Body Weight; Eunuchism; Gigantism; Glucagon; Gonadotropins; Growth Disorders; Growth Hormone; Humans; Hypoglycemia; Hypopituitarism; Insulin; Male; Pituitary Hormones; Thyrotropin; Vasopressins

Topics: Aerosols; Body Weight; Child; Child, Preschool; Chlorothiazide; Diabetes Insipidus; Diuresis; Drinking Behavior; Drug Resistance; Follow-Up Studies; Humans; Male; Oils; Osmolar Concentration; Polyuria; Psychophysiologic Disorders; Thirst; Urination Disorders; Vasopressins; Water Deprivation; Water-Electrolyte Balance

Topics: Animals; Autoradiography; Body Weight; Buffers; Carbon Isotopes; DNA; Hypothalamo-Hypophyseal System; Hypothalamus; In Vitro Techniques; Microscopy, Electron; Nerve Tissue Proteins; Neuroglia; Neurosecretion; Nucleotidyltransferases; Pituitary Gland, Posterior; Rats; Ribonucleases; RNA; Starvation; Tritium; Uracil Nucleotides; Vasopressins; Water Deprivation

Topics: Animals; Body Weight; Diabetes Insipidus; Diuresis; Drinking Behavior; Hypothalamus; Male; Potassium; Rats; Sodium; Vasopressins; Water-Electrolyte Balance

Topics: Animals; Body Weight; Diabetes Insipidus; Diabetic Nephropathies; Female; Food Preferences; Kidney; Potassium; Rats; Rats, Inbred Strains; Vasopressins; Water-Electrolyte Balance

Topics: Animals; Body Weight; Kinetics; Male; Rats; Time Factors; Vasopressins; Water Deprivation

Topics: Animals; Body Weight; Depression, Chemical; Diabetes Insipidus; Diet; Feeding Behavior; Female; Furosemide; Heterozygote; Homozygote; Kidney; Osmolar Concentration; Rats; Sodium; Thirst; Urea; Urine; Vasopressins

Topics: Adolescent; Adult; Blood Pressure; Body Weight; Diet, Sodium-Restricted; Female; Humans; Male; Osmolar Concentration; Posture; Radioimmunoassay; Renin; Vasopressins; Water Deprivation

Topics: Adaptation, Physiological; Animals; Body Weight; Brain; Cell Nucleolus; Desert Climate; Gerbillinae; Hypothalamus; Mice; Organ Size; Rats; Rodentia; Species Specificity; Vasopressins

Topics: Animal Nutritional Physiological Phenomena; Animals; Body Weight; Diabetes Insipidus; Disease Models, Animal; Drinking Behavior; Eating; Feeding Behavior; Female; Glucose; Milk; Osmolar Concentration; Rats; Rats, Inbred Strains; Sodium Chloride; Solutions; Vasopressins; Water; Water-Electrolyte Balance

Topics: Adaptation, Physiological; Animals; Biological Assay; Body Weight; Desert Climate; Diet; Kidney Concentrating Ability; Mice; Physiology, Comparative; Pituitary Gland, Posterior; Rats; Vasopressins; Water Deprivation

Topics: Animals; Body Weight; Diabetes Insipidus; Diuresis; Genotype; Hypothalamo-Hypophyseal System; Mice; Organ Size; Pituitary Gland, Posterior; Potassium; Sodium; Vasopressins; Water

Balance studies have been carried out to evaluate the influence of vasopressin-induced volume expansion on acid-base equilibrium in normal dogs and in dogs with steady-state metabolic acidosis induced by the administration of 5-7 mmoles/kg per day of hydrochloric acid.Hypotonic expansion in dogs with metabolic acidosis (mean plasma bicarbonate concentration 14 mEq/liter) produced a marked increase in renal acid excretion that restored plasma bicarbonate concentration to normal (20-21 mEq/liter) despite continued ingestion of acid. When water was restricted during the vasopressin period, and fluid retention thus prevented, no increase in acid excretion or plasma bicarbonate concentration occurred. From these findings we conclude that hypotonic expansion is a potent stimulus to renal hydrogen ion secretion and greatly facilitates the renal removal of an acid load. Normal dogs subjected to expansion demonstrated no change in net acid excretion or in plasma bicarbonate concentration even in the face of a marked diuresis of sodium and chloride and a reduction in plasma sodium concentration to approximately 110 mEq/liter. The animals did, however, regularly lose potassium, a finding that clearly indicates an acceleration of distal sodiumcation exchange. On the basis of these observations, and the findings in the expanded acidotic dogs, we suggest that in the expanded normal dogs acceleration of sodium-hydrogen exchange was responsible for preventing a bicarbonate diuresis and for stabilizing plasma bicarbonate concentration. These studies clearly demonstrate that chronic hypotonic expansion exerts a major influence on the renal regulation of acid-base equilibrium. The exact nature of the mechanism responsible for the increase in sodium-hydrogen exchange during hypotonic expansion remains to be determined.

Topics: Acid-Base Equilibrium; Acidosis; Animals; Bicarbonates; Blood Volume; Body Weight; Carbon Dioxide; Chlorides; Diuresis; Dogs; Female; Hydrochloric Acid; Hydrogen-Ion Concentration; Hypotonic Solutions; Kidney; Osmolar Concentration; Potassium; Sodium; Sodium Chloride; Vasopressins

Topics: Animals; Anura; Body Weight; Chlorpropamide; Drug Synergism; Vasopressins; Water

Topics: Angiotensin II; Animals; Blood Volume; Body Weight; Deficiency Diseases; Dogs; Female; Hematocrit; Hyponatremia; Male; Renin; Sodium Chloride; Vasopressins

Topics: Age Factors; Angiotensin II; Animals; Animals, Newborn; Autonomic Nervous System; Blood Pressure; Body Weight; Carotid Sinus; Denervation; Drug Synergism; Epinephrine; Ganglionic Blockers; Heart Rate; Morpholines; Nephrectomy; Neurons, Afferent; Pressoreceptors; Quaternary Ammonium Compounds; Rabbits; Renin; Vasopressins

Topics: Animals; Body Weight; Chlorides; Depression, Chemical; Diuresis; Dogs; Female; Glomerular Filtration Rate; Kidney; Kidney Concentrating Ability; Natriuresis; Osmolar Concentration; Potassium; Regional Blood Flow; Sodium; Urine; Vasopressins; Water-Electrolyte Balance

Topics: Adolescent; Body Weight; Child, Preschool; Diabetes Insipidus; Diuresis; Female; Humans; Infant; Infant, Newborn; Kidney Concentrating Ability; Male; Osmolar Concentration; Pituitary-Adrenal Function Tests; Vasopressins

Topics: Adrenal Insufficiency; Adrenalectomy; Animals; Anxiety; Blood; Body Weight; Diuresis; Dogs; Handling, Psychological; Hematocrit; Humans; Hydrocortisone; Osmolar Concentration; Potassium; Renin; Sodium; Sodium Chloride; Vasopressins

Topics: Adrenal Cortex Hormones; Body Weight; Coma; Electrocardiography; Electroencephalography; Female; Humans; Hyponatremia; Hypopituitarism; Middle Aged; Sodium; Vasopressins; Water; Water-Electrolyte Balance

Topics: Adult; Altitude; Blood Urea Nitrogen; Body Weight; Carbon Dioxide; Dehydration; Diuresis; Furosemide; Heart Rate; Hematocrit; Hemoglobinometry; Humans; Hypoxia; Male; Oxygen; Partial Pressure; Plasma Volume; Time Factors; Vasopressins; Water

Topics: Animals; Body Weight; Diabetes Insipidus; Female; Male; Rats; Rats, Inbred Strains; Renin; Sex Factors; Vasopressins; Water

Topics: Adrenal Glands; Animals; Body Weight; Circadian Rhythm; Depression, Chemical; Estrus; Female; Gonadotropins, Pituitary; Gonads; Light; Male; Melatonin; Organ Size; Periodicity; Pituitary Gland; Pregnancy; Rats; Sex Factors; Stimulation, Chemical; Time Factors; Vasopressins

Topics: Animals; Body Weight; Creatinine; Diet; Diuresis; Lithium; Male; Methylthiouracil; Rats; Sodium Chloride; Tannins; Time Factors; Vasopressins; Water; Water Deprivation

Topics: Body Weight; Cold Temperature; Hot Temperature; Humans; Sweating; Vasopressins

Topics: Adrenal Glands; Amino Acid Sequence; Amino Acids; Animals; Avoidance Learning; Body Weight; Chromatography, Ion Exchange; Conditioning, Psychological; Hypophysectomy; Male; Organ Size; Peptides; Pituitary Gland; Pituitary Hormones, Anterior; Pituitary Hormones, Posterior; Rats; Swine; Testis; Thymus Gland; Tissue Extracts; Vasopressins

Topics: Adult; Aged; Body Weight; Cholesterol; Diuresis; Female; Glomerular Filtration Rate; Humans; Hydrocortisone; Hyponatremia; Kidney; Male; Middle Aged; Myxedema; Osmolar Concentration; Potassium; Sodium; Thyroid Gland; Thyroid Hormones; Thyroxine; Vasopressins; Water-Electrolyte Balance

Topics: Body Weight; Humans; Sweating; Vasopressins

Topics: Adrenocorticotropic Hormone; Animals; Barbiturates; Body Weight; Drinking Behavior; Electroshock; Humans; Male; Rats; Seizures; Stress, Physiological; Substance Withdrawal Syndrome; Substance-Related Disorders; Vasopressins

Topics: Animals; Body Weight; Brain; Electrolytes; Male; Organ Size; Osmolar Concentration; Pituitary Gland; Positive-Pressure Respiration; Rats; Urine; Vasopressins; Ventilators, Mechanical

Topics: Aged; Blood Glucose; Body Weight; Chlorpropamide; Depression, Chemical; Diabetes Insipidus; Diuresis; Female; Glyburide; Humans; Hydrochlorothiazide; Hypoglycemic Agents; Male; Middle Aged; Natriuresis; Osmolar Concentration; Potassium; Sulfonylurea Compounds; Tolbutamide; Vasopressins

Topics: Adrenal Insufficiency; Adrenalectomy; Animals; Blood Pressure; Blood Volume; Body Weight; Cortisone; Dogs; Potassium; Sodium; Sodium Chloride; Vasopressins

Topics: Animals; Body Weight; Dehydration; Hypothalamo-Hypophyseal System; Male; Neurosecretion; Osmolar Concentration; Rats; Secretory Rate; Vasopressins; Water

Topics: Aldosterone; Body Weight; Desoxycorticosterone; Humans; Hyponatremia; Male; Middle Aged; Osmolar Concentration; Potassium; Sodium; Urine; Vasopressins; Water-Electrolyte Balance

Topics: 17-Ketosteroids; Aldosterone; Blood Volume; Body Weight; Feces; Humans; Hydrocortisone; Male; Natriuresis; Oxytocin; Renin; Sodium; Vasopressins; Water Deprivation; Water-Electrolyte Balance

Topics: Animals; Blood Pressure; Body Weight; Desoxycorticosterone; Heart; Hypertension; In Vitro Techniques; Male; Nephrectomy; Norepinephrine; Perfusion; Potassium; Rats; Sodium Chloride; Tail; Vascular Diseases; Vascular Resistance; Vasopressins

Topics: Adult; Age Factors; Aldosterone; Body Weight; Capillary Permeability; Edema; Female; Humans; Hyperaldosteronism; Male; Middle Aged; Mineralocorticoid Receptor Antagonists; Natriuresis; Posture; Renin; Sex Factors; Sodium; Vasopressins; Water-Electrolyte Balance

Topics: Animals; Animals, Newborn; Body Weight; Depression, Chemical; Female; Glucose; Hypothalamo-Hypophyseal System; Lactation; Lactose; Mammary Glands, Animal; Milk; Oxytocin; Pregnancy; Prolactin; Rats; Vasopressins

Topics: Adrenocortical Hyperfunction; Animals; Body Weight; Diabetes Insipidus; Diuresis; Genes, Dominant; Genes, Lethal; Glomerular Filtration Rate; Hypertrophy; Kidney Concentrating Ability; Kidney Glomerulus; Kidney Tubules; Mice; Organ Size; Syndactyly; Vasopressins

Topics: Animals; Body Weight; Diabetes Insipidus; Estrus; Female; Hypothalamus; Isotonic Solutions; Lactation; Potassium; Pregnancy; Pregnancy Complications; Pregnancy, Animal; Rats; Sodium Chloride; Stereotaxic Techniques; Urine; Vasopressins; Water-Electrolyte Balance

Topics: Adult; Animals; Body Fluids; Body Weight; Bromine; Cachexia; Celiac Disease; Child; Creatinine; Dogs; Emaciation; Extracellular Space; Female; Humans; Hypoproteinemia; Kwashiorkor; Lipid Metabolism; Male; Nutrition Disorders; Osmosis; Postgastrectomy Syndromes; Potassium Isotopes; Protein Biosynthesis; Proteins; Radioisotope Dilution Technique; Radioisotopes; Rats; Sodium; Sodium Isotopes; Thinness; Tritium; Vasopressins; Water-Electrolyte Balance

Topics: Animals; Avoidance Learning; Behavior, Animal; Body Weight; Cerebral Cortex; Drinking Behavior; Feeding Behavior; Male; Motivation; Osmolar Concentration; Rats; Urine; Vasopressins

Topics: 17-Hydroxycorticosteroids; Adenocarcinoma; Adrenal Gland Neoplasms; Adrenal Glands; Adrenal Insufficiency; Aldosterone; Body Weight; Female; Humans; Hyponatremia; Lung Neoplasms; Middle Aged; Neoplasm Metastasis; Sodium; Vasopressins; Water-Electrolyte Balance

1. The effect of bilateral lesions in the anterior hypothalamus on the histology and content of melanocyte-stimulating hormone (MSH) of the pars intermedia has been studied in the adult male rat.2. By 7-15 days striking histological changes, suggestive of hyperactivity, were evident. These changes were accompanied by an elevated MSH content, which was particularly noticeable at 7 days.3. By 7 days there was an increase in the acid phosphatase activity of pars intermedia cells, as demonstrated histochemically.4. It was concluded that a hypothalamic control system exists for the mammalian pars intermedia and may involve both inhibitory and excitatory components.

Topics: Acid Phosphatase; Animals; Body Weight; Electric Injuries; Hypothalamus; Male; Melanocyte-Stimulating Hormones; Oxytocin; Pituitary Gland; Rats; Vasopressins

Topics: Animals; Anura; Biological Assay; Body Weight; Methods; Vasopressins

Topics: Adolescent; Adrenocorticotropic Hormone; Blood Glucose; Body Height; Body Weight; Brain Neoplasms; Child; Craniopharyngioma; Exercise Test; Feeding and Eating Disorders; Female; Glucose Tolerance Test; Gonadotropins; Growth; Growth Hormone; Humans; Hypothalamus; Insulin; Male; Obesity; Pituitary Neoplasms; Postoperative Complications; Radioimmunoassay; Thirst; Thyrotropin; Vasopressins; Vision Disorders

Topics: Adrenal Glands; Adrenocorticotropic Hormone; Animals; Body Weight; Circadian Rhythm; Corticosterone; Corticotropin-Releasing Hormone; Female; Male; Mathematics; Methods; Periodicity; Pituitary Gland; Pituitary Gland, Posterior; Rats; Sex Factors; Thyrotropin; Time Factors; Vasopressins

Topics: Amphetamine; Animals; Body Weight; Dehydration; Guinea Pigs; Hematocrit; Hypothalamo-Hypophyseal System; Hypothalamus; Male; Pituitary Gland; Reserpine; Stimulation, Chemical; Sympathetic Nervous System; Synapses; Synaptic Transmission; Vasopressins; Water; Water Deprivation

Topics: Adolescent; Adult; Aged; Body Weight; Child; Diuretics; Edema; Female; Heart Failure; Hematocrit; Humans; Lung; Lung Compliance; Male; Middle Aged; Oxygen; Positive-Pressure Respiration; Pulmonary Edema; Radiography; Respiration, Artificial; Respiratory Function Tests; Respiratory Insufficiency; Sodium; Vasopressins; Water-Electrolyte Balance

Topics: Animals; Body Weight; Diabetes Insipidus; Drinking Behavior; Feeding Behavior; Female; Hypothalamo-Hypophyseal System; Hypothalamus; Pituitary Gland; Rats; Stereotaxic Techniques; Vasopressins

Topics: Biopsy; Body Temperature; Body Weight; Brain Diseases; Calcium; Child; Child, Preschool; Chlorides; Creatine; Dehydration; Diabetes Insipidus; Diagnosis, Differential; Diet; Diuresis; Feeding and Eating Disorders; Female; Humans; Hydrochlorothiazide; Hypothalamus; Infant; Kidney; Male; Mineralocorticoid Receptor Antagonists; Obesity; Osmolar Concentration; Osmosis; Piperidines; Potassium; Sodium; Urography; Vasopressins

Topics: Animals; Aorta; Arteriosclerosis; Blood Pressure; Body Weight; Calcium; Cholesterol; Diet; Female; Lipids; Male; Rabbits; Reserpine; Vasopressins

Topics: Animals; Blood Chemical Analysis; Body Weight; Dehydration; Hematocrit; Male; Osmolar Concentration; Oxytocin; Pituitary Gland; Rats; Vasopressins

Topics: Animals; Body Weight; Extracellular Space; Female; Inulin; Potassium; Pregnancy; Pregnancy, Animal; Rats; Sodium; Spironolactone; Vasopressins; Water-Electrolyte Balance

Polydipsia and polyuria are pronounced in chickens of a selected strain and this diabetes insipidus is inherited. The kidneys of such birds are capable of an antidiuretic response when lysine vasopressin or arginine vasotocin is injected. Osmotic pressure and sodium concentration of the plasmas of normal and mutant chickens are identical. Chicks predicted to have diabetes insipidus on the basis of parental pedigree are polydipsic.

Topics: Animals; Arginine; Body Weight; Chickens; Diabetes Insipidus; Female; Kidney Tubules; Lysine; Male; Molecular Biology; Mutation; Osmotic Pressure; Polyuria; Poultry Diseases; Sodium; Thirst; Turkeys; Vasopressins; Vasotocin; Water-Electrolyte Balance

Topics: Adult; Body Weight; Female; Glomerular Filtration Rate; Heart Valve Diseases; Heart Valve Prosthesis; Humans; Hydrocephalus; Hypertonic Solutions; Hyponatremia; Male; Osmolar Concentration; Sodium; Sodium Chloride; Vasopressins

Topics: Animals; Body Weight; Brain Chemistry; Brain Edema; Liver; Muscles; Rats; Vasopressins; Water; Water Intoxication; Water-Electrolyte Balance

Topics: Adult; Aldosterone; Body Weight; Diuretics; Edema; Female; Heart Function Tests; Histamine; Humans; Kinins; Liver Function Tests; Prediabetic State; Pregnancy; Psychophysiologic Disorders; Vasopressins; Water-Electrolyte Balance

Topics: Animals; Body Weight; Kidney; Kidney Concentrating Ability; Mice; Organ Size; Sodium Chloride; Vasopressins; Water Deprivation

Topics: Animals; Anura; Body Weight; Carbon Tetrachloride; Diuresis; Hypothalamo-Hypophyseal System; Hypothalamus; Male; Stimulation, Chemical; Vasopressins; Water

Topics: Animals; Body Weight; Diuresis; Drinking; Drug Tolerance; Eating; Mice; Morphine; Pituitary Gland; Potassium; Sodium; Vasopressins

Topics: Animals; Anura; Biological Assay; Body Weight; Methods; Species Specificity; Vasopressins

Topics: Adrenal Glands; Adrenalectomy; Animals; Body Weight; Desoxycorticosterone; Drinking; Male; Rats; Starvation; Urine; Vasopressins; Water

Topics: Adult; Aged; Body Weight; Extracellular Space; Female; Humans; Middle Aged; Obesity; Urination; Urine; Vasopressins; Water; Water-Electrolyte Balance

Topics: Adult; Body Weight; Diabetic Retinopathy; Epilepsy, Tonic-Clonic; Female; Humans; Hyponatremia; Male; Middle Aged; Palliative Care; Pituitary Gland; Postoperative Complications; Tremor; Vasopressins

Topics: Animals; Anura; Body Weight; Female; Male; Vasopressins

Topics: Adrenal Glands; Adrenalectomy; Adrenocorticotropic Hormone; Animals; Ascorbic Acid; Body Weight; Corticosterone; Diabetes Insipidus; Genetics; Hypothalamo-Hypophyseal System; Organ Size; Pituitary Gland; Pituitary-Adrenal System; Rats; Stress, Physiological; Vasopressins

Topics: Aged; Aldosterone; Body Weight; Carcinoma, Bronchogenic; Erythrocytes; Feces; Female; Humans; Hyponatremia; Male; Middle Aged; Muscles; Vasopressins; Water-Electrolyte Balance

Topics: Adrenal Glands; Adrenocorticotropic Hormone; Blood Pressure; Body Temperature; Body Weight; Child; Corticosterone; Pharmacology; Physiology; Pituitary Diseases; Pituitary Gland; Polysaccharides; Polysaccharides, Bacterial; Vasopressins

Topics: Amphibians; Animals; Anura; Biological Evolution; Biological Transport; Body Weight; Chordata; Endocrinology; Fishes; Oxytocin; Pharmacology; Phylogeny; Physiology, Comparative; Pituitary Hormones, Posterior; Research; Sharks; Sodium; Vasopressins; Vasotocin; Vertebrates; Water; Water-Electrolyte Balance

Topics: Adolescent; Anemia; Anemia, Sickle Cell; Black People; Body Weight; Child; Dehydration; Humans; Urine; Vasopressins; Water-Electrolyte Balance

Topics: Animals; Body Weight; Chemical Phenomena; Chemistry; Dexamethasone; Female; Goats; Growth Hormone; Humans; Hypophysectomy; Insulin; Insulin, Long-Acting; Lactation; Milk; Pregnancy; Pregnancy, Animal; Prolactin; Protamines; Research; Triiodothyronine; Vasopressins

Topics: Adrenal Medulla; Adrenocorticotropic Hormone; Arginine Vasopressin; Body Weight; Cold Temperature; Epinephrine; Guanethidine; Hypophysectomy; Iodine Isotopes; Methylthiouracil; Pharmacology; Phenoxybenzamine; Rats; Research; Tannins; Thyroid Function Tests; Thyroid Gland; Thyrotropin; Thyrotropin-Releasing Hormone; Vasopressins

Topics: Blood Pressure; Body Weight; Diuresis; Edema; Female; Glomerulonephritis; Humans; Hypertension; Hypertension, Renal; Inulin; Kidney; Kidney Function Tests; Nephrosclerosis; Osmolar Concentration; Pathology; Pharmacology; Pre-Eclampsia; Pregnancy; Pregnancy Complications, Cardiovascular; Proteinuria; Vasopressins

Observations are presented on two patients with chronic compulsive polydipsia who showed a relative defect in renal concentrating capacity. After excluding all possible metabolic and renal causes of hyposthenuria and after obtaining normal kidney biopsies, both patients were studied in metabolic balance on a constant diet under the following conditions: (a) dehydration (loss of 3-5% body weight), (b) water loading and response to hypertonic saline, and (c) water loading and response to intravenous vasopressin (Pitressin). Throughout these studies the following parameters were observed: plasma and urine osmolality, glomerular filtration rate (inulin), renal plasma flow (P.A.H.), osmolar clearance and clearance of free water. In both patients the concentration defect was not related to variations in glomerular filtration rate or osmotic load. There was no correlation between the degree of hypoosmolality and the renal concentrating defect. Contrary to reports from other laboratories, restriction of water intake and chronic administration of intramuscular vasopressin did not correct the concentration defect.

Topics: Arginine Vasopressin; Body Weight; Compulsive Behavior; Drinking; Glomerular Filtration Rate; Humans; Inulin; Kidney; Kidney Diseases; Osmolar Concentration; Osmosis; Polydipsia; Polyuria; Saline Solution, Hypertonic; Thirst; Vasopressins

Topics: Body Weight; Dextrans; Infant, Newborn; Infant, Premature; Kidney; Kidney Function Tests; Metabolism; Osmosis; Physiology; Sensory Receptor Cells; Sodium; Urine; Vasopressins; Water; Water-Electrolyte Balance

Topics: Adrenocorticotropic Hormone; Aldosterone; Animals; Arginine Vasopressin; Blood Pressure; Body Weight; Cortisone; Desoxycorticosterone; Hormones; Hypertension; Norepinephrine; Progesterone; Rats; Rats, Inbred SHR; Research; Sodium Chloride; Spironolactone; Stilbenes; Testosterone; Thyroid Hormones; Vasopressins

Topics: Arginine Vasopressin; Body Fluids; Body Weight; Creatine; Creatinine; Hypertension; Natriuresis; Sodium; Urine; Vasopressins

Topics: Arginine Vasopressin; Body Weight; Pituitary Gland; Pituitary Gland, Intermediate; Vasopressins