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 exchangeability of toad bladder epithelial cell potassium has been investigated. An insignificant amount of cellular potassium exchanged with mucosal medium 42K. From the rate of uptake of 42K into the cells from the serosal medium at least two cellular potassium pools were identified. The more rapidly exchanging pool contained about one-quarter to one-third of the cellular potassium and exchanged with a half-time of about 30 min. It was from this pool that potassium was lost from cells exposed to ouabain or to a potassium-free medium. In addition, when 3.5 mM rubidium replaced 3.5 mM potassium in sodium Ringer's the epithelial cells lost in 60 min about one-quarter of their cellular potassium in exchange for rubidium. Inhibition of transepithelial sodium transport by amiloride, 10(-5) mM, seemed to depress the rate of potassium uptake into the more rapidly exchanging pool without affecting total cellular potassium content. However, stimulation of transepithelial sodium transport by vasopressin appeared not to affect the rate of potassium uptake. The rate of potassium uptake into this pool seemed much less than that required for a tight 1:1 coupling between transepithelial sodium transport and potassium uptake. The remaining cellular potassium exchanged at a much slower rate and even after 19 hours of incubation only 67% of cellular potassium was labelled. If this slower exchanging potassium represents a single pool, 99% of cellular potassium would be labelled only after incubation with 42K for 56 hours.
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PMID:Relationships between serosal medium potassium concentration and sodium transport in toad urinary bladder. III. Exchangeability of epithelial cellular potassium. 81 31

Investigations effected in 16 subjects of 20-69 years at bed rest after bone fractures demonstrated, in an interval of 10-27 days after surgery, normal plasma sodium concentration and a decreased urinary elimination, an increased plasma potassium concentration but a decreased urinary output. The osmotic changes were not significant. The plasma vasopressin activity was increased. Three urinary aldosterone determinations showed an increased output. The serum calcium level was within normal limits but its urinary output was initially slightly decreased, contrary to its augmented elimination after simple voluntary bed rest, as results from literature. The hydroxyproline elimination was increased, demonstrating an active collagen metabolism.
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PMID:Hydroelectrolytic changes caused by prolonged clinical recumbency. 81 41

Ultrastrucal studies of the mouse neurohypophysis, under various experimental conditions, revealed a number of neurosecretory granules (NSG) bearing single pseudopodia-like protrusions. Some NSG adhered to the axolemma via pseudopodia; other NSG, distant from the axolemma, budded electron lucent microvesicles from the tip of the pseudopod. Pseudopodia counts were made on electron micrographs, and calculated as a percentage of the NSG population. In neural lobes from intact mice, small numbers of pseudopodia were observed (0.3%); the count increased significantly after injections of large doses of horseradish peroxidase (HRP) (9.4--14.5%); hypertonic saline augmented the count, as did histamine. In vitro incubation experiments with isolated neural lobes in Krebs Ringer revealed concomitant pseudopodia formation and elevated vasopressin release (measured by antidiuretic bioassay) in the presence of HRP and di-butyryl cyclic AMP respectively. Histamine and excess potassium also increased hormone secretion, but did not induce pseudopodia formation in vitro; pseudopodia were observed neither in controls, nor in the presence of ineffective secretagogues. It is suggested that the pseudopod may represent the active site on the granule membrane. Different ultrastructural images of granule release suggest that several modes of hormone release may be operative in the neurohypophysis. The role of HRP in pseudopodia formation and vasopressin release is enigmatic.
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PMID:Pseudopodia formation by neurosecretory granules. 83 Apr 28

Various parameters of renal function were studied before, during, and after the infusion of physiological increments of angiotensin II directly into one renal artery of anesthetized dogs. During water diuresis and during antidiuresis induced with exogenous antidiuretic hormone (ADH), angiotensin II consistently reduced UNaV, UKV, and CPAH, and increased the filtration fraction in the infused kidney. Urinary osmolality was increased only in the presence of ADH, while during water diuresis angiotensin II had no apparent effect on urinary osmolality or flow rate. During saline diuresis, a mean increment of angiotensin II concentration of 14 pg/ml was sufficient to significantly reduce UNaV and urinary flow rate. Changes in CCr, CPAH, and filtration fraction did not correlate with changes in sodium excretion, and intracortical distribution of blood flow remained unaltered. These data support the hypothesis that normal circulating levels of angiogensin II play a direct renal role in the control of sodium, potassium, and water homeostasis, and that angiotensin II exerts a direct, stimulatory effect on tubular sodium reabsorption independent of changes in GFR, RPF, filtration fraction, or intracortical distribution of blood flow.
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PMID:Stimulation of renal sodium reabsorption by angiotensin II. 85 Nov 87

35S-cysteine injected adjacent to the supraoptic nucleus (SON) of the rat is rapidly incorporated into proteins. These 35S-cysteine-labeled proteins in the SON (1-24 h after injection) were separated by polyacrylamide gel electrophoresis, and the distribution of radioactive proteins on the gels was analyzed. 1 h after injection, about 73% of the radioactivity appeared in two peaks (both about 20,000 mol wt). With time, these peaks (putative precursors of neurophysin) decreased, as a 12,000 mol wt peak (containing two distinct neurophysins) increased in radioactivity. Both the 20,000- and 12,000-mol wt proteins are transported into the axonal (median eminence) and nerve terminal (posterior pituitary) regions of the rat hypothalamo-neurohypophysial system. Conversion of the larger precursor protein to the smaller neurophysin appears to occur, in large part, intra-axonally during axonal transport. Six distinct 35S-cysteine-labeled peptides (less than 2500 mol wt), in addition to arginine vasopressin and oxytocin, are also synthesized in the SON and transported to the posterior pituitary where they are released together with labeled neurophysin by potassium depolarization in the presence of extracellular calcium. These data provide support for the hypothesis that the neurohypophysial peptides (vasopressin and oxytocin) and neurophysins are derived from the post-translational clevage of protein precursors synthesized in the SON, and that the conversion process can occur in the neurosecretory granule during axonal transport.
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PMID:Biosynthesis and axonal transport of rat neurohypophysial proteins and peptides. 85 41

The syndrome of inappropriate ADH secretion ("SIADH") was first recognized 1935 by Roth et al. and described in detail 1957 by Schwartz et al. The clinical symptoms (hyponatremia, hypertonicity of urine and inability to excrete a water load) are caused by inadequately elevated ADH secretion under a variety of situations and diseases. Some recent work was focused on the pathogenesis of this syndrome and new clinical findings (low plasma levels of uric acid and potassium) as well as special forms ("SIADH" without elevated vasopressin levels in plasma) are thought to be of relevance. New therapeutical recommendations will be discussed.
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PMID:[The syndrome of inappropriate secretion of vasopressin (SIADH) (author's transl)]. 85 83

The renal effects of vasopressin (VP) in water-loaded and hydropenic conscious dogs were examined with and without the previous administration of prostaglandin (PG) synthesis inhibitors (indomethacin and meclophenamate). The parameters studied were: urinary output, sodium and potassium excretion, plasma and urinary osmotic concentration, total renal blood flow, mean arterial pressure, heart rate, and the clearance and extraction ratio of p-aminohippuric acid and inulin. The infusion of VP caused antidiuresis and marked saluresis during water diuresis, whereas it was found to be diuretic and saluretic in hydropenic animals. Inhibition of PG synthesis greatly enhanced the antidiuretic activity of VP and abolished its saluretic and diuretic actions. Changes in renal water and solute excretion and changes in the hemodynamic parameters are uncorrelated. It is concluded that intrarenal PGs may play an important role in modulating the renal action of VP.
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PMID:Renal response to vasopressin after inhibition of prostaglandin synthesis. 86 Jul 62

Prolactin is an important osmoregulatory hormone in several lower vertebrate species. The present study was undertaken to clarify the effects of prolactin, if any, on human renal function. Eight normal adult male subjects on a 150 mEq sodium (Na), 60 mEq potassium (K) diet for 5 days were studied during 12 h of oral water (H2O) loading on 2 consecutive days. On day 1, after a 6 h control period, a 1 ml normal saline placebo was given im; on day 2, 25 mg of ovine prolactin (OP) was substituted. The subjects were supine and received a constant infusion of Na and K. After OP, serum prolactin rose from 6.9+/-0.8 ng/ml to 15.0+/-2.5 ng/ml (P less than .01) at 1 h, 27.6+/-4.0 ng/ml (P less than .002) at 2 h, 33.1+/-4.3 ng/ml (P less than .001) at 3 h and remained elevated for the remaining 3 h of study. The ovine prolactin had 20-25% of the potency of human prolactin in the human prolactin radioimmunoassay system. In response to OP, free H2O clearance (CH2O) promptly decreased from 10.1 +/- .06 ml/min to 6.1 +/- .05 ml/min (P less than 0.1) at 1 h, to a nadir of 5.1+/-.3 ml/min (P less than .001) at 2 h, and returned to control levels by 4 h. CH2O was unchanged after placebo, and urinary Na and K excretion, creatinine and osmolar clearance (COSM), plasma Na, K, osmolality and aldosterone were unchanged after OP or placebo. Control plasma vasopressin was 1.0+/-0.1 micronU/ml and was not changed after prolactin (1.1+/-0.1 micronU/ml at 1 h, 1.1+/-0.1 micronU/ml at 2 h and 1.1+/-0.1 micronU/ml at 3 h). The ovine prolactin contained 2 micronU of immunoassayable vasopressin per microng of powder. Aqueous vasopressin, 50 mU (containing in 25 mg of ovine prolactin), produced a decrease in CH2O not significantly different from prolactin in 6 water loaded subjects. Four different subjects given 100 mg of OP had decreased CH2O from 8.3+/-0.3 to 2.7+/-0.7 ml/min at 1 h (P less than .001) and to 2.8+/-0.7 ml/min at 2 h (P less than .01). Control plasma osmolality was 301+/-4 mOsm/1 and decreased to a maximum of 288+/-5 mOsm/1 4 h after OP (P less than .001). After prolactin administration, plasma vasopressin rose from 0.44+/-0.15 to 0.80+/-0.41 micronU/ml (P =NS) at 1 h. The transient antidiuresis in response to ovine prolactin is due to contamination of the preparation with vasopressin. Prolactin does not acutely influence renal electrolyte excretion and probably does not influence water excretion in man.
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PMID:The effects of ovine prolactin on water and electrolyte excretion in man are attributable to vasopressin contamination. 87 May 13

Cytochemical methods using silver proteinate, silver methenamine an potassium ferrocyanide + OsO4 for ultrastructural detection of glycoproteins allow, in the posthypophysis and the magnocellular nuclei of the rat, differentiation of two types of fibres and neurons: one type containing negative granules with a homogenous content of low electron density, the second type containing granules which demonstrate a ring shaped deposit either of silver or of potassium ferrocyanide-osmium complex, likely to be related to a glycoprotein component. The difference between these two types is increased by prestaining "en bloc" with uranyl acetate before the silver proteinate reaction. A similar investigation was carried out on the vasopressin deficient Brattleboro rat; the neurosecretory material, present in some endings and neurons only, is of the nonreactive type, so that it appears justified to correlate the reactivity of granules with vasopressin, consequently to distinguish neurones and fibres containing vasopressin from those in which oxytocin is quantitatively the main hormonal peptide. This conclusion is strongly supported by the fact that percentages of reactive and negative endings, as determined on this basis in the posthypophysis of normal rats from two different strains, are in good agreement with biochemical data reported in the literature.
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PMID:Cytochemical duality of neurosecretory material in the hypothalamo-posthypophysial system of the rat as related to hormonal content. 87 84

Clomipramine inhibited pressor responses to potassium ions and vasopressin in the rat mesenteric vascular bed with an ID50 of about 1.8 microgram/ml against both pressor agents and the actions of indomethacin and PG2 on the clomipramine effect suggested that the drug may have been antagonising the action of an endogenous PG. This was supported by the inhibitory action of clomipramine on PG2 actions on guinea-pig ileum. A lower concentration also inhibited pressor responses to noradrenaline and angiotensin (ID50 about 9 ng/ml): inhibition was increased by PG2 and reduced by indomethacin. In this preparation potassium and vasopressin act primarily by stimulating calcium entry from the extracellular fluid whereas noradrenaline and angiotensin act primarily by releasing calcium from intracellular or membrane-bound stores. Our results can be explained by two actions: 1. a PG-antagonist action of clomipramine at the cell membrane and 2. a selectve inhibitory effect on release of intracellular calcium. Clomipramine may prove useful in studying PG and calcium-dependent mechanisms.
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PMID:Actions of the tricyclic antidepressant clomipramine on responses to pressor agents. Interactions with prostaglandin E2. 89 8


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