Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mean resting concentration of cytosolic free Ca2+ [( Ca2+]i) in parenchymal liver cells, as determined with the intracellular Ca2+ indicator quin2, was lowered by about 30% in hypothyroidism (0.17 microM vs. 0.27 microM in normal cells). The [Ca2+]i level in hypothyroid cells at 10 s following stimulation by noradrenaline (1 microM) was about 64% lower than in normal cells (0.33 microM vs. 1.0 microM). The response to noradrenaline in hypothyroid cells was slower in onset (significant at 5 s vs. 3 s in euthyroid cells), and the maximum of the initial [Ca2+]i increase was reached later (14 s vs. 8 s in normal cells). In hypothyroid hepatocytes the initial increase was followed by a slow but prolonged secondary increase in [Ca2+]i. With vasopressin similar results were found. Chelation of extracellular Ca2+ with EGTA immediately prior to stimulation had no effect on the initial [Ca2+]i increase. Treatment with T3 in vivo (0.5 micrograms/100 g body weight daily during 3 days) completely restored the basal and stimulated [Ca2+]i in hypothyroid cells. The half-maximally effective dose of noradrenaline was the same in euthyroid and hypothyroid liver cells (1.8 X 10(-7) M). Hypothyroidism had no significant effect on the number of alpha 1-receptors determined by [3H]prazosin labeling in crude homogenate fractions, while the Kd for [3H]prazosin was 21% lower than in the euthyroid group. These results show that thyroid hormone has a general stimulating effect on intracellular Ca2+ mobilization by Ca2+-mobilizing hormones, probably at a site distal to the binding of the agonist to its receptor. The results also support our idea that thyroid hormone may control metabolism during rest and activation, at least partially, by altering Ca2+ homeostasis.
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PMID:Effect of hypothyroidism on the cytosolic free Ca2+ concentration in rat hepatocytes during rest and following stimulation by noradrenaline or vasopressin. 300 1

The hypothalamic paraventricular nucleus (PVN) has been implicated in a remarkable number of functions including control of pituitary-adrenocortical activity in response to stress, body fluid homeostasis, milk ejection reflex, prolactin secretion, thyroid hormone secretion, analgesia, food intake, gastrointestinal functions, cardiovascular functions, and control of pineal melatonin synthesis. Paraventricular neurons produce hormones of key importance in neuroendocrine regulation such as vasopressin (VP), oxytocin (OX), 41-residue corticotropin releasing factor (CRF), thyrotropin releasing hormone (TRH), somatostatin (SOM) and the putative prolactin releasing factor vasoactive intestinal polypeptide (VIP). Three recent advances pertinent to the organization of the PVN include: (1) the evidence that the structure of the PVN is compartmental in nature, topographically segregated cellular units seem to carry out different functions; (2) the discovery that paraventricular neurons are capable of expressing a multitude of neuromediators simultaneously, thus cellular units can be best specified by a certain combination of neuromediators; (3) evidence that the composition of the neuromediator "cocktail" in individual neurons is variable and depends on the physiological status of the animal. Hence, the PVN may be best considered as a dynamic mosaic of chemically specified subgroups of neurons. The flexibility of neurotransmitter status in paraventricular neurons may play a central role of a functional plasticity of fixed anatomical circuits.
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PMID:Dynamism of chemoarchitecture in the hypothalamic paraventricular nucleus. 304 19

The pattern of age-induced changes in each endocrine system is unique. Both hormone levels and target organ responsivity are altered in the aging endocrine-cardiovascular system. Serum levels of vasopressor hormones both increase (norepinephrine) and decrease (renin, aldosterone). Target organ responses to beta-adrenergic stimulation in the heart and probably also in vascular smooth muscle decrease due to postreceptor changes. These effects contribute to the clinical problems of hypertension and orthostatic hypotension which characterize the elderly. Aging produces mild carbohydrate intolerance and a minimal increase in fasting serum glucose in healthy, nonobese individuals, primarily due to decreasing postreceptor responsiveness to insulin. Aging decreases the metabolism of thyroxine, including its conversion to triiodothyronine, but clinically significant alterations of thyroid hormone levels do not occur. Changes in the end-organ response to thyroid hormones, however, significantly alter the clinical presentation of thyroid diseases. Aging shifts the serum vasopressin-serum osmolality relationship toward higher serum vasopressin levels probably due to altered baroreceptor input, probably contributing to the tendency toward hyponatremia in the elderly. Aging slows the metabolism of cortisol, but glucocorticoid levels in the human are essentially unaltered by age. However, recent data indicate that delta-5 adrenal steroids decrease markedly in both men and women. Nodules in the anterior pituitary, the thyroid, and the adrenal increase in frequency with aging. Finally, the reproductive system is primarily altered by endocrine cell death, by unknown mechanisms, resulting in decreased estrogen and testosterone levels in women and men. This most obvious age-related endocrine change turns out to be incompletely understood and is not representative of most age-related endocrine changes. Despite characterization of these many age-related alterations in endocrine systems, therapeutic issues often remain unexplored, and more data are needed in many areas.
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PMID:Age and the endocrine system. 391 1

1. Vasopressin has been shown to activate the thyroid in some species, and also to be released into the bloodstream after emotional and other stresses.2. Emotional stimuli applied to sheep have previously been shown to increase thyroid secretion and the possible influence of vasopressin in this process has been investigated. Sheep bearing exteriorized thyroid glands were used, so that thyroid vein blood could be collected in undisturbed conscious animals.3. (125)I or (131)I (50 muc) was injected I.M. into the sheep; 4-7 days later, samples of thyroid vein blood were collected at 10 min intervals for 4 hr, and the concentration of total and protein bound (125)I or (131)I was measured. Intravenous infusions of 0.3, 3.0 or 31 m-u./min arginine or lysine vasopressin, or close arterial infusions of 3.0 or 31 m-u./min arginine vasopressin were administered 1.5 hr after commencement of blood sampling. Blood flow from the thyroid was measured by a plethysmographic technique during similar experiments.4. No significant changes in thyroid hormone secretion were observed as a result of vasopressin infusion, and it was concluded that vasopressin release does not play a part in the activation of the thyroid resulting from emotional stimulus in the sheep.
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PMID:The effect of vasopressin on hormone secretion and blood flow from the thyroid vein in sheep with exteriorized thyroids. 417 34

A 65-year-old female with general malaise, anorexia and marked emaciation was studied by secretion stimulation tests on 6 anterior pituitary hormones. Only ACTH showed no response and the other 5 hormones responded normally. The basal value of antidiuretic hormone was normal. She was found to be suffered from primary hypothyroidism. Though neither antithyroid antibodies nor other autoantibodies were found, Hashimoto's thyroiditis was confirmed by a thyroid open biopsy. Neoplastic lesions of the hypophysis were ruled out by various X-ray and CT examinations of the sella turcica as well as the brain. The case was concluded to be isolated ACTH deficiency associated with Hashimoto's thyroiditis. The substitution therapy using small doses of adrenocortical hormone and thyroid hormone has kept her well and she has been living normally for these five years.
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PMID:Isolated ACTH deficiency associated with Hashimoto's thyroiditis: report of a case. 608 96

The response to an osmolar load (750 ml 2.5% NaCl solution iv preceded by 500 ml water by mouth) was studied in 20 patients with Sheehan's syndrome and 12 normal women. Sodium and osmolality were determined in plasma and urine and arginine-vasopressin (AVP) was measured by RIA in urine. The test was performed in each patient when untreated (group P), after hydrocortisone replacement alone (group F), and combined hydrocortisone and thyroid hormone replacement (group F+T). After the osmolar loading, maximum urinary osmolality in the patients was lower than in the normal women and remained unaffected by both hydrocortisone alone and hydrocortisone and thyroid hormone. Comparison of the mean hourly urinary volume before and after NaCl infusion demonstrated an increase in group P, a decrease in group C, and no change in groups F and F+T. Although free water clearance became negative in all groups, values in groups P, F, and F+T were constantly above that of group C. None of the patients in groups P and F had a significant rise in urine AVP excretion during or after NaCl infusion. Those in group F+T had a slight AVP response which was less than in normal women. Impaired response of AVP to an osmolar load appears to be a constant feature of Sheehan's syndrome even without overt diabetes insipidus.
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PMID:Arginine-vasopressin in postpartum panhypopituitarism: urinary excretion and kidney response to osmolar load. 669 47

The role of the antidiuretic hormone-independent mechanisms underlying the impairment of water excretion in hypothyroidism remains controversial. We examined the excretion of an oral water load (50 ml/kg b.w.) over a 3-hour period before and after the administration of aldosterone, methylprednisolone, both aldosterone and methylprednisolone, and triiodothyronine in 12 hypothyroid and 7 age-matched control Wistar rats of the homozygous Brattleboro strain (DI). Conscious animals were studied to circumvent the adverse influence of anesthetics and to facilitate the re-examination of the same animals. At baseline, the hypothyroid DI rats exhibited a marked impairment in their response to water administration. In comparison to control DI rats they had a lower urine volume, CH2O, CH2O/V and creatinine clearance, and higher urine osmolality (p less than 0.005-less than 0.001). Because of the possibility of decreased delivery of filtrate due to dehydration in the DI animals, a separate group of DI rats received saline in place of the water load. Despite improvement in urine flow with saline, CH2O generation remained decreased in the hypothyroid DI rats. Methylprednisolone increased both urine volume (p less than 0.001) and CH2O (p less than 0.001) in the hypothyroid group, but CH2O formation remained below the values obtained in the control animals. While aldosterone and methylprednisolone alone and in combination improved utilization of distally-delivered filtrate for the formation of CH2O (p less than 0.02-0.005), neither hormone, either alone or in combination, fully corrected the dilution defect. In contrast, the administration of triiodothyronine fully normalized all the observed abnormalities in the hypothyroid rats, suggesting that thyroid hormone deficiency is directly responsible for the abnormal water-excretion in experimental hypothyroidism.
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PMID:Effects of aldosterone, methylprednisolone and triiodothyronine on the response to water loading in the conscious hypothyroid rat with diabetes insipidus. 672 5

A 45-year-old woman with myxedema coma due to primary hypothyroidism manifested hyponatremia, impaired water excretion, and elevated urine osmolarity as well as natriuresis suggestive of a syndrome of inappropriate antidiuretic hormone secretion. However, plasma vasopressin was undetectable or very low and plasma aldosterone levels were suppressed in the presence of hyponatremia. Subsequent replacement therapy with levothyroxine caused a rapid decline in sodium clearance which was independent of the change in glomerular filtration rate, and corrected the impaired water excretion and hyponatremia. Plasma vasopressin levels returned to the normal range after the correction of hyponatremia. Thus, the results indicate that neither vasopressin nor aldosterone plays a dominant role in the pathogenesis of the hyponatremia in this patient. It appears that thyroid hormone deficiency itself caused the derangement of tubular cell function, which resulted in the development of the impaired water excretion and hyponatremia.
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PMID:Hyponatremia without inappropriate secretion of vasopressin in a case of myxedema coma. 717 13

We have recently reported that hypothyroidism increases immunoreactive (IR)-vasoactive intestinal polypeptide (VIP) and VIP mRNA content in both parvocellular and magnocellular neurons of the rat, hypothalamic paraventricular nucleus (PVN). As VIP can stimulate vasopressin (AVP) secretion, we conducted an anatomical investigation to determine whether VIP-containing neurons in other regions of the brain that are involved with homeostatic mechanisms of water and salt conservation are also affected by hypothyroidism. The distribution and intensity of VIP immunostaining in neurons and fibers of the magnocellular-neurohypophysial system, including the hypothalamic PVN, supraoptic nucleus (SON) and accessory magnocellular cell groups, circumventricular subfornical organ (SFO), preoptic and anterior hypothalamus, midline thalamus, subthalamic zona incerta and posterior septal nuclei were studied using a highly sensitive immunocytochemical technique and unbiased neuronal counting methods, based on the optical dissector principle. Hypothyroidism increased the intensity of VIP immunostaining and/or the number/section, percentage and numerical density of IR-VIP neurons in the PVN, SON, nucleus circularis, periventricular preoptic nucleus of the hypothalamus and SFO. In addition, IR-VIP perikarya and/or fibers in the hypothalamic medial preoptic area and anterior periventricular nucleus, nucleus reuniens of the thalamus and dorsal fornix-triangular septal nucleus complex were also apparent in the hypothyroid animals while no immunostaining was seen in these areas in control animals. No quantitative and/or qualitative modifications in IR-VIP neurons and fibers were noted in the anterior hypothalamic area, suprachiasmatic nucleus, thalamic paraventricular nucles an subthalamic zona incerta between hypothyroid and control animals. These findings suggest an inverse relationship between thyroid hormone and VIP content and/or distribution of IR-VIP neurons in specific forebrain regions involved in the control of AVP release, extracellular fluid volume, thirst, blood pressure and anterior pituitary secretion. This raises the possibility that changes in fluid homeostasis and cardiovascular function occurring in hypothyroidism may be mediated, at least in part, by VIP-producing neurons in diverse regions of the brain.
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PMID:Effect of hypothyroidism on vasoactive intestinal polypeptide-immunoreactive neurons in forebrain-neurohypophysial nuclei of the rat brain. 755

The effect of peptide and nonpeptide substance P antagonists on prolactin (PRL) and growth hormone (GH) secretion was evaluated in three-dimensional rat anterior pituitary cell aggregates. [D-Arg1,D-Phe5,D-Trp7,9,Leu11]Substance P inhibited basal growth hormone (GH) release at a concentration range of 1-10 microM. At higher concentrations (50 microM), the analogue inhibited basal prolactin (PRL) release but provoked a tenfold stimulation of GH release. However, these latter two effects could neither be mimicked nor antagonized by the tachykinins substance P (10 microM), neurokinin A (10 microM), and neurokinin B (3.3 microM). The effects could also not be explained by agonism or antagonism at the level of other receptors (e.g., vasopressin, bombesin, angiotensin II, thyroid hormone-releasing hormone, vasoactive intestinal peptide, dopamine, adrenaline, acetylcholine). Remarkably the nonpeptide substance P antagonists R 30732 (10 microM), R 32602 (10 microM), and CP-96,345 (10 microM) showed a similar inhibition of PRL release and a stimulation of GH release. At a one hundredfold lower concentration, sufficient to block substance P receptors in other tissues. CP-96,345 did not affect PRL or GH release. It is concluded that substance P antagonists, when used at high concentrations, have profound intrinsic activities on PRL and GH release that are not mediated by substance P receptors. The failure of the more potent substance P antagonist, CP-96,345, to influence basal PRL or GH release when used at lower concentrations suggests that endogenous substance P in the anterior pituitary does not play a tonic paracrine role on GH or PRL secretion.
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PMID:Unexpected effects of peptide and nonpeptide substance P receptor antagonists on basal prolactin and growth hormone release in vitro. 768 Jan 28


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