pituitrin and Weight-Loss

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

A regulatory effect of arginine vasopressin (AVP) on sweat water conservation has been hypothesized but not definitively evaluated. AVP-mediated insertion of sweat and salivary gland aquaporin-5 (AQP5) water channels through activation of the vasopressin type 2 receptor (V2R) remains an attractive, yet unexplored, mechanism that could result in a more concentrated sweat with resultant decreased water loss. Ten runners participated in a double-blind randomized control treadmill trial under three separate pharmacological conditions: a placebo, V2R agonist (0.2 mg desmopressin), or V2R antagonist (30 mg tolvaptan). After a familiarization trial, runners ran for 60 min at 60% of peak speed followed by a performance trial to volitional exhaustion. Outcome variables were collected at three exercise time points: baseline, after the steady-state run, and after the performance run. Body weight losses were <2% across all three trials. Significant pharmacological condition effects were noted for urine osmolality [F = 84.98; P < 0.0001] and urine sodium concentration ([Na(+)]) [F = 38.9; P < 0.0001], which verified both pharmacological activation and inhibition of the V2R at the kidney collecting duct. Plasma osmolality and [Na(+)] demonstrated significant exercise (F = 26.0 and F = 11.1; P < 0.0001) and condition (F = 5.1 and F = 3.8; P < 0.05) effects (osmolality and [Na(+)], respectively). No significant exercise or condition effects were noted for either sweat or salivary [Na(+)]. Significant exercise effects were noted for plasma [AVP] (F = 22.3; P < 0.0001), peak core temperature (F = 103.3; P < 0.0001), percent body weight change (F = 6.3; P = 0.02), plasma volume change (F = 21.8; P < 0.0001), and thirst rating (F = 78.2; P < 0.0001). Performance time was not altered between conditions (P = 0.80). In summary, AVP acting at V2R does not appear to regulate water losses from body fluids other than renal excretion during exercise.

Topics: Adult; Antidiuretic Hormone Receptor Antagonists; Benzazepines; Biomarkers; Deamino Arginine Vasopressin; Double-Blind Method; Exercise; Female; Hormone Antagonists; Humans; Male; Middle Aged; Neurophysins; Osmolar Concentration; Physical Endurance; Plasma Volume; Protein Precursors; Receptors, Vasopressin; Running; Signal Transduction; Sodium; Sweat; Sweat Glands; Sweating; Thirst; Time Factors; Tolvaptan; Vasopressins; Water-Electrolyte Balance; Weight Loss; Young Adult

Water intake occurs following a period of high-intensity intermittent exercise (HIIE) due to sensations of thirst yet this does not always appear to be caused by body water losses. Thu.s, the aim was to assess voluntary water intake following HIIE. Ten healthy males (22 ± 2 y, 75.6 ± 6.9 kg, VO2(peak) 57.3 ± 11.4 m · kg(-1) · min(-1); mean ± SD) completed two trials (7-14 d apart). Subjects sat for 30 min then completed an exercise period involving 2 min of rest followed by 1 min at 100% VO2(peak repeated for 60 min (HIIE) or 60 min continuously at 33% VO2(peak) (LO). Subjects then sat for 60 min and were allowed ad libitum water intake. Body )mass was measured at start and end of trials. Serum osmolality, blood lactate, and sodium concentrations, sensations of thirst and mouth dryness were measured at baseline, postexercise and after 5, 15, 30, and 60 min of recovery. Vasopressin concentration was measured at baseline, postexercise, 5 min, and 30 min. Body mass loss over the whole trial was similar (HIIE: 0.77 ± 0.50; LO: 0.85 ± 0.55%; p = .124). Sweat lost during exercise (0.78 ± 0.22 vs. 0.66 ± 0.26 L) and voluntary water intake during recovery (0.416 ± 0.299 vs. 0.294 ± 0.295 L; p < .05) were greater in HIIE. Serum osmolality (297 ± 3 vs. 288 ± 4 mOsmol · kg(-1)), blood lactate (8.5 ± 2.7 vs. 0.7 ± 0.4 mmol · L(-1)), serum sodium (146 ± 1 vs. 143 ± 1 mmol · L(-1)) and vasopressin (9.91 ± 3.36 vs. 4.43 ± 0.86 pg · ml(-1)) concentrations were higher after HIIE (p < .05) and thirst (84 ± 7 vs. 60 ± 21) and mouth dryness (87 ± 7 vs. 64 ± 23) also tended to be higher (p = .060). Greater voluntary water intake after HIIE was mainly caused by increased sweat loss and the consequences of increased serum osmolality mainly resulting from higher blood lactate concentrations.

Topics: Adult; Body Water; Dehydration; Drinking; Drinking Water; Exercise; Heart Rate; Humans; Lactic Acid; Male; Mouth; Osmolar Concentration; Physical Exertion; Rest; Sodium; Sweat; Sweating; Thirst; Vasopressins; Water-Electrolyte Balance; Weight Loss; Young Adult

On two separate occasions six trained subjects (peak oxygen consumption [VO2peak] 4.41/min) rode for 60 min at 70% of VO2peak and then to exhaustion at 90% of VO2peak to determine the effects of mild dehydration on high-intensity cycling performance time in the heat (32 degrees C, 60% relative humidity, wind speed 3 km/h). In one trial (F) subjects ingested a 400 ml bolus of 20 mmol/l NaCl immediately before, and then as repetitive 120 ml feedings every 10 min during the first 50 min of exercise. In the other trial they did not ingest fluid (NF) either before or during exercise. The order of testing was in a counter-balanced random sequence. For the first 60 min of exercise mean (+/- SD) VO2 (2.90 +/- 0.39 vs 2.93 +/- 0.38 l/min) and respiratory exchange ratio (RER; 0.95 +/- 0.03 vs 0.94 +/- 0.04) values were similar between F and NF trials. However, weight loss was significantly reduced during F compared to NF (0.16 +/- 0.39 vs 1.30 +/- 0.22 kg; p < 0.005) and high-intensity cycling time to exhaustion was significantly increased (9.8 +/- 3.9 vs 6.8 +/- 3.0 min; p < 0.005). Increased cycling times to exhaustion in the F trial were not associated with any measurable differences in heart rate (HR), body temperature, respiratory gas exchange, leg muscle power over 5 sec, or the degree to which fluid ingestion reduced the level of dehydration within the group. Only the ratings of perceived exertion (RPE) and plasma anti diuretic hormone (ADH) concentrations were significantly increased in the NF trial compared to the F trial.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Bicycling; Body Temperature; Dehydration; Fluid Therapy; Heart Rate; Hot Temperature; Humans; Humidity; Male; Muscle Contraction; Oxygen Consumption; Perception; Physical Endurance; Physical Exertion; Psychomotor Performance; Respiration; Sodium Chloride; Time Factors; Vasopressins; Weight Loss; Wind

Linfoma B intravascular hipotalamico en una paciente inmunocompetente.

Topics: Aged; Combined Modality Therapy; Confusion; Cranial Irradiation; Female; Glucocorticoids; Humans; Hypothalamus; Hypothyroidism; Immunocompetence; Lymphoma, B-Cell; Neoplasm Invasiveness; Positron Emission Tomography Computed Tomography; Sleep Disorders, Circadian Rhythm; Vascular Neoplasms; Vasopressins; Weight Loss

Behavioral modifications for the treatment of obesity, including caloric restriction, have notoriously low long-term success rates relative to bariatric weight-loss surgery. The reasons for the difference in sustained weight loss are not clear. One possibility is that caloric restriction alone activates the stress-responsive hypothalamo-pituitary-adrenocortical (HPA) axis, undermining the long-term maintenance of weight loss, and that this is abrogated after bariatric surgery. Accordingly, we compared the HPA response to weight loss in five groups of male rats: (1) high-fat diet-induced obese (DIO) rats treated with Roux-en-Y gastric bypass surgery (RYGB, n = 7), (2) DIO rats treated with vertical sleeve gastrectomy (VSG, n = 11), (3) DIO rats given sham surgery and subsequently restricted to the food intake of the VSG/RYGB groups (Pair-fed, n = 11), (4) ad libitum-fed DIO rats given sham surgery (Obese, n = 11) and (5) ad libitum chow-fed rats given sham surgery (Lean, n = 12). Compared with Lean controls, food-restricted rats exhibited elevated morning (nadir) non-stress plasma corticosterone concentration and increased hypothalamic corticotropin-releasing hormone and vasopressin mRNA expression, indicative of basal HPA activation. This was largely prevented when weight loss was achieved by bariatric surgery. DIO increased HPA activation by acute (novel environment) stress and this was diminished by bariatric surgery-, but not pair-feeding-, induced weight loss. These results indicate that the HPA axis is differentially affected by weight loss from caloric restriction versus bariatric surgery, and this may contribute to the differing long-term effectiveness of these two weight-loss approaches.

Topics: Animals; Caloric Restriction; Corticosterone; Corticotropin-Releasing Hormone; Diet, High-Fat; Disease Models, Animal; Gastrectomy; Gastric Bypass; Hypothalamo-Hypophyseal System; Male; Obesity; Pituitary-Adrenal System; Rats, Long-Evans; RNA, Messenger; Stress, Physiological; Time Factors; Vasopressins; Weight Loss

Increased dietary salinity suppressed reproduction of the xeric adapted golden spiny mouse, Acomys russatus. Testicular and uterine mass were reduced, suppressed spermatogenesis and vaginal closure were observed. The anti-diuretic hormone, vasopressin (VP), was suggested to mediate such effects. However, increased dietary salinity did not affect reproductive status of a mesic adapted population of the common spiny mouse, A. cahirinus. In the present study, the effect of exogenous VP on the reproductive status and energy balance of both males and females of A. russatus and of a mesic population of A. cahirinus was tested. Vasopressin (Sigma, 50 microg/kg) was injected intraperitoneally in three-day intervals for four weeks. In VP-treated A. russatus, spermatogenesis was significantly suppressed while the change in testis mass did not show significant difference. Both control and VP-treated females lost body mass (W(b)) significantly and the latter also exhibited a higher energy expenditure compared to their male counterparts. VP did not affect reproductive status in both sexes of A. cahirinus. Also it did not have a significant effect on W(b), energy intake, and energy expenditure in this species. Our results support the idea that VP mediates the effects of increased diet salinity on reproduction in A. russatus. The results also reinforce previous knowledge that different physiological systems could be integrated by a single biochemical signal.

Topics: Animals; Diet; Energy Metabolism; Estrus; Female; Male; Murinae; Organ Size; Oxygen Consumption; Reproduction; Salinity; Sex Characteristics; Spermatogenesis; Testis; Uterus; Vasopressins; Weight Loss

1. This study presents a time course analysis of the messenger RNA (mRNA) levels of c-fos, vasopressin (VP), and oxytocin (OT) in the paraventricular (PVN) and supraoptic nucleus (SON), following acute and chronic dehydration by water deprivation. 2. Male Wistar rats were separated into five groups: nondehydrated (control group) and dehydrated for 6, 24, 48 and 72 h. Following water deprivation, animals were decapitated, their blood was collected for hematocrit, osmolality, and plasma sodium measurements, and brains were removed for dissection of both PVN and SON. 3. As expected, the hematocrit, osmolality, plasma sodium, and weight loss were increased after water deprivation. In SON, a significant increase in both VP and OT mRNA expression was observed 6 h after dehydration reaching a peak at 24 h and returning to basal levels of expression at 72 h. In the PVN, an increase in both VP and OTmRNA expression occurred 24 h after dehydration. At 72 h the VP and OT mRNA expression levels had decreased but they were still at higher levels than those detected in control animals. 4. These results suggest that SON is the first nucleus to respond to the dehydration stimulus. Additionally, we also observed an increase in c-fos mRNA expression in both PVN and SON 6 h after water deprivation, which progressively decreased 24, 48, and 72 h after the onset of water deprivation. Therefore, it is possible that c-fos may be involved in the modulation of VP and OT genes, regulating the mRNA expression levels on a temporally distinct basis within the PVN and SON.

Topics: Animals; Dehydration; Gene Expression; Hematocrit; Hypothalamus, Anterior; Male; Osmolar Concentration; Oxytocin; Paraventricular Hypothalamic Nucleus; Proto-Oncogene Proteins c-fos; Rats; Rats, Wistar; RNA, Messenger; Sodium; Vasopressins; Water Deprivation; Weight Loss

The suprachiasmatic nuclei (SCN) of the hypothalamus contain the master mammalian circadian clock, which is mainly reset by light. Temporal restricted feeding, a potent synchronizer of peripheral oscillators, has only weak influence on light-entrained rhythms via the SCN, unless restricted feeding is coupled with calorie restriction, thereby altering phase angle of photic synchronization. Effects of daytime restricted feeding were investigated on the mouse circadian system. Normocaloric feeding at midday led to a predominantly diurnal (60%) food intake and decreased blood glucose in the afternoon, but it did not affect the phase of locomotor activity rhythm or vasopressin expression in the SCN. In contrast, hypocaloric feeding at midday led to 2-4 h phase advances of three circadian outputs, locomotor activity rhythm, pineal melatonin, and vasopressin mRNA cycle in the SCN, and it decreased daily levels of blood glucose. Furthermore, Per1 and Cry2 oscillations in the SCN were phase advanced by 1 and 3 h, respectively, in hypocalorie- but not in normocalorie-fed mice. The phase of Per2 and Bmal1 expression remained unchanged regardless of feeding condition. Moreover, the shape of behavioral phase-response curve to light and light-induced expression of Per1 in the SCN were markedly modified in hypocalorie-fed mice compared with animals fed ad libitum. The present study shows that diurnal hypocaloric feeding affects not only the temporal organization of the SCN clockwork and circadian outputs in mice under light/dark cycle but also photic responses of the circadian system, thus indicating that energy metabolism modulates circadian rhythmicity and gating of photic inputs in mammals.

Topics: Animals; ARNTL Transcription Factors; Basic Helix-Loop-Helix Transcription Factors; Blood Glucose; Cell Cycle Proteins; Circadian Rhythm; Cryptochromes; Darkness; Eating; Energy Intake; Energy Metabolism; Flavoproteins; Food Deprivation; Gene Expression Regulation; Light; Male; Melatonin; Mice; Mice, Inbred C3H; Motor Activity; Nuclear Proteins; Period Circadian Proteins; Photic Stimulation; Pineal Gland; Suprachiasmatic Nucleus; Time Factors; Transcription Factors; Vasopressins; Weight Loss

Many previous studies have shown that aquaporin-2 (AQP2), the vasopressin-regulated water channel, is excreted in the urine and that the excretion increases in response to vasopressin. Moreover, recently a close correlation between AQP2 excretion in urine and kidney AQP2 expression has been demonstrated, showing that urinary excretion of AQP2 is a reliable indicator for AQP-2 function. As head-out water immersion causes an expansion in the central vascular volume equal to that induced by 2 liters of saline, without modifying plasma composition, we used immersion in water to evaluate if the response to acute expansion of the central vascular volume could involve vasporessin (AVP) and AQP2. In healthy subjects, concentrations of plasma atrial natriuretic factor (ANF) and AVP, and urinary AQP2 were measured during a 2-hour immersion period. In all subjects, immersion caused a prompt and marked increase in immunoreactive ANF (23.0 +/- 2.12 pg/ml at second hour vs. 2.17 +/- 0.42 pg/ml at baseline) and in urinary excretion of AQP2 (23.9 +/- 2. 69 pmol/mg creatinine at second hour vs. 4.42 +/- 0.14 pmol/mg creatinine at baseline), while a significant decrease was found in plasma AVP. Recovery was associated with a prompt return to pre-study levels. These findings demonstrate that heat-out water immersion stimulates urinary excretion of AQP2 in absence of an increase in plasma AVP.

Topics: Adult; Aquaporin 2; Aquaporin 6; Aquaporins; Atrial Natriuretic Factor; Blood Pressure; Diuresis; Female; Humans; Male; Reference Values; Vasopressins; Water; Water-Electrolyte Balance; Weight Loss

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

Stress can cause disturbance of homeostasis to result in illness. Stress can also induce various gene expression in different neuronal systems. For example, nutritional stress induced by acute food deprivation upregulates corticotropin-releasing factor (CRF) mRNA, whereas osmotic stress increases vasopressin (VP) mRNA. However, it is unknown if nutritional stress induced by chronic food deprivation has synergistic effects on CRF and VP mRNAs. We have used in situ hybridization in conjunction with quantitative autoradiography to demonstrate that nutritional stress induced by a 4-day food deprivation results in a body-weight loss with a significant decrease of CRF mRNAs, but not VP mRNAs in the paraventricular hypothalamic nucleus (PVN) of Sprague-Dawley rats. The present study has thus indicated that a chronic nutritional stress does not have synergistic effects on CRF and VP mRNAs. The decrease of CRF mRNAs is obviously related to the body-weight loss induced by food deprivation. This study thus supports a notion that the CRF, but not VP, neurons in the PVN play an important role in their neuroadaptation associated with body weight loss. Thus, it is conceivable that downregulated CRF neurons in the hypothalamus could be involved in pathogenesis of human eating disorder with severe weight loss, whereas upregulated CRF neurons could be associated with an opposite form of the eating disorder that causes obesity.

Topics: Animals; Autoradiography; Corticotropin-Releasing Hormone; Down-Regulation; Food Deprivation; Image Processing, Computer-Assisted; In Situ Hybridization; Male; Paraventricular Hypothalamic Nucleus; Rats; Rats, Sprague-Dawley; RNA, Messenger; Vasopressins; Weight Loss

Oxytocin, vasopressin and corticotrophin releasing factor have anorectic properties when injected centrally. We studied the kinetics of these neuropeptides by injecting fenfluramine, a drug which reduces food intake, in Long Evans rats. The drug was injected daily through a double chronic cannula implanted above the paraventricular nucleus of the hypothalamus; the rats had free access to pure macronutrients. The rats lost weight during the treatment. Their total caloric intake decreased mostly because the carbohydrate intake decreased, while the protein intake increased slightly. The synthesis and release of brain oxytocin and vasopressin were increased and the release of corticotrophin releasing factor was stimulated. The neuropeptides could be involved in fenfluramine-triggered mechanisms.

Topics: Animals; Appetite Depressants; Blood Glucose; Corticotropin-Releasing Hormone; Eating; Fenfluramine; Hypothalamus; Injections; Kinetics; Male; Neuropeptides; Oxytocin; Paraventricular Hypothalamic Nucleus; Rats; Vasopressins; Weight Loss

Rats given restricted feeding and allowed free access to activity wheels increase activity, decrease food intake, and lose body weight compared to nonexercised controls. The phenomenon is of interest because of the relationship between exercise and anorexia nervosa. This study determined if another factor that energizes behavior in rats, water deprivation, produces similar exercise-induced weight loss. Rats were maintained on a restricted water schedule (10 min/day) combined with free access to running wheels and food; controls had no wheel access or were food deprived only. Both water-deprived groups consumed similar amounts of food and water, with the exercised group losing more body weight. Plasma osmolality, hematocrit, and posterior pituitary vasopressin content were equivalent in the two water-deprived groups, indicating similar hydrational status. It is concluded that the weight loss effect in water-deprived rats is due to excessive voluntary exercise, and that other factors that energize behavior should produce a similar effect.

Topics: Animals; Appetite; Eating; Male; Physical Exertion; Pituitary Gland, Posterior; Rats; Rats, Sprague-Dawley; Vasopressins; Water Deprivation; Water-Electrolyte Balance; Weight Loss

1. The vasopressin mRNA in the adult male rat hypothalamus is modulated in two distinct ways by a dehydration stimulus. In addition to the well-established increase in transcript abundance, it has recently been demonstrated that the vasopressin mRNA poly(A) tail increases in length. 2. We have studied the ontogeny of poly(A) tail length modulation in neonates in response to milk deprivation and found that poly(A) tail length changes are age dependent. In neonates older than 12 days of age, the vasopressin mRNA poly(A) tail length increased with milk deprivation and this effect became more marked in older animals. However, in rats 5 to 9 days old, milk deprivation resulted in a detectable though not significant decrease in vasopressin mRNA poly(A) tail length. 3. As milk deprivation is a combination of dehydration and starvation, we investigated the effect of the latter stimulus in more mature animals. We found that starvation modifies the length of the vasopressin mRNA poly(A) tail in a manner opposite that due to dehydration. 4. Our data indicate a novel mode of regulation of the vasopressin mRNA, namely, poly(A) tail shortening. This system provides a model for future studies concerning the adaptive role of poly(A) tail length modulation in response to physiological stimuli.

Topics: Adaptation, Physiological; Age Factors; Animals; Animals, Newborn; Dehydration; Female; Hypothalamus; Male; Osmolar Concentration; Poly A; Rats; Rats, Sprague-Dawley; RNA, Messenger; Starvation; Vasopressins; Weight Loss

As endogenous opiates are known to be involved in regulation of appetite, an obese patient with panhypopituitarism and frequent episodes of ravenous hunger was treated with the oral opiate antagonist naltrexone for 13 months. This resulted in loss of body weight and attacks of severe hunger. The increased serum prolactin concentration and the dose of vasopressin required for substitution could be reduced. Long-term application of opiate antagonists may be useful in related cases.

Topics: Adult; Appetite; Drug Administration Schedule; Female; Humans; Hypopituitarism; Naltrexone; Obesity, Morbid; Prolactin; Vasopressins; Weight Loss