pituitrin and Rodent-Diseases

Topics: Animals; Chlorpropamide; Diabetes Insipidus; Disease Models, Animal; Diuresis; Kidney; Osmolar Concentration; Rats; Rodent Diseases; Sodium; Urine; Vasopressins

Topics: Animals; Arginine; Carbamazepine; Chlorpropamide; Clofibrate; Cyclic AMP; Diabetes Insipidus; Hypothalamus; Kidney Diseases; Lithium; Methoxyflurane; Peptide Biosynthesis; Protein Biosynthesis; Rats; Rodent Diseases; Tetracycline; Vasopressins; Vermont

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

Hamsters of the BIO 14.6 strain characteristically develop cardiomyopathy as they age, and hamsters of this strain have overt signs of heart failure by 11 months of age. Plasma levels of the posterior pituitary hormone arginine-vasopressin (AVP) were found to be elevated (approximately 2-fold) in 11 month old BIO 14.6 hamsters, compared to age-matched hamsters of a control strain. AVP appeared inappropriately elevated in these animals, since they were neither hyperosmotic nor markedly hypotensive. The elevated levels of AVP observed in these animals appears to contribute to vasomotor tone, since intravenous administration of a specific antagonist of the vasoconstrictor action of AVP [d(CH2)5Ome(TYR)AVP] elicited a fall in arterial pressure (9 +/- 2 mm Hg, n = 6, p less than 0.05). The AVP antagonist had no effect on arterial pressure in hamsters of a control strain, and vehicle administration had no effect on arterial pressure in either strain. These data indicate that inappropriately elevated levels of AVP contribute to the cardiovascular state of myopathic hamsters. Since elevated plasma AVP has been noted in human congestive heart failure, these results suggest that AVP may contribute to the cardiovascular status during congestive heart failure.

Topics: Age Factors; Animals; Cardiomyopathies; Cricetinae; Disease Models, Animal; Heart Failure; Mesocricetus; Rodent Diseases; Vasoconstriction; Vasopressins

Recently it was reported that vasopressin facilitates the development of resistance to the analgestic action of morphine. Therefore, the development of tolerance to daily administration of morphine-HCl (10 mg/kg i.p.) was studied in a series of trials on a hot plate using rats with hereditary diabetes insipidus (DI), which lack the ability to synthesize vasopressin. In contrast to heterozygous DI rats, who developed full tolerance after the fifth injection, homozygous DI rats showed a delayed development of tolerance. Substitution of HO-DI rats with either arginine-8-vasopressin (3 mug/rat, s.c. daily) or the endocrinologically inert fragment of vasopressin desglycinamide lysine-8-vasopressin (5 mug/100 g, s.c. daily) restored the impaired development of tolerance towards normal. The data support the notion that vasopressin is important to the development of tolerance to narcotic analgesics and that its mechanism of action is dissociated from its endocrine effect but rather resembles that of its known influence on memory consolidation.

Topics: Analgesia; Animals; Arginine Vasopressin; Diabetes Insipidus; Drug Tolerance; Heterozygote; Homozygote; Lypressin; Male; Memory; Morphine; Rats; Rats, Inbred Strains; Rodent Diseases; Vasopressins

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: Adenylyl Cyclases; Animals; Creatinine; Cyclic AMP; Diabetes Insipidus; Diuresis; Drug Antagonism; Ethanol; Glomerular Filtration Rate; Isoproterenol; Models, Biological; Osmolar Concentration; Pentobarbital; Propranolol; Rats; Receptors, Adrenergic; Rodent Diseases; Urine; Vasopressins

Topics: Animals; Diabetes Insipidus; Disease Models, Animal; Female; Kidney Tubules; Male; Mice; Neurosecretion; Organ Size; Oxytocin; Pituitary Gland, Posterior; Rats; Rodent Diseases; Uterus; Vasopressins

Topics: Animals; Chromatography, Ion Exchange; Diabetes Insipidus; Heterozygote; Homozygote; Iodine Isotopes; Methods; Osmolar Concentration; Pituitary Gland; Radioimmunoassay; Rats; Rodent Diseases; Urine; Vasopressins; Water Deprivation

Topics: Animals; Blood; Cell Nucleolus; Diabetes Insipidus; Hypertrophy; Hypothalamo-Hypophyseal System; Hypothalamus; Kidney Concentrating Ability; Kidney Tubules; Mice; Neurosecretion; Osmolar Concentration; Rodent Diseases; Urine; Vasopressins

Topics: Animals; Biological Assay; Diabetes Insipidus; Female; Hypothalamus; In Vitro Techniques; Metabolism, Inborn Errors; Muscle, Smooth; Oxytocin; Pituitary Gland, Posterior; Rats; Rodent Diseases; Urine; Uterus; Vasopressins; Water-Electrolyte Balance

Topics: Arginine Vasopressin; Disease; Epinephrine; Hexamethonium; Hypertension; Rats; Rodent Diseases; Thiourea; Vasoconstrictor Agents; Vasopressins