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)

Organ cultures of the guinea pig hypothalamo-neurohypophysial complex synthesize the octapeptide hormone, vasopressin, a specific product of the neurosecretory cells of the supraoptic nucleus. Inhibitors of both protein and RNA synthesis (cycloheximide and bromotubercidin respectively) were found to block vasopressin biosynthesis. In the presence of bromotubercidin, the apparent half-time of decline in the rate of hormone biosynthesis was about 28 h. Colchicine inhibited the distal transport of vasopressin into the posterior pituitary. Ultrastructural studies on colchicine-treated cultures indicated the neuronal stalks were intact and that neurotubules were still present. The narcotic drug, levorphanol at 10-7 M and 10-9 M was found to inhibit RNA synthesis by 20 percent. At these concentrations it had no demonstrable effect on vasopressin synthesis. Cultures established from animals that had been rendered tolerant to narcotics also had no observable alterations in vasopressin biosynthesis, although the initial pituitary vasopressin content of these cultures was reduced by about 35 percent. Various pharmacologic and biologic compounds were tested for their effects on vasopressin biosynthesis in organ cultures. Dibutyryl cyclic AMP, estradiol-17beta, nicotine, nerve growth factor (NGF), and pineal extract all had no effects under the present experimental regimen. Medium conditioned by the presence of fetal hypothalami of 40-55 days gestation produced a 2-4 fold increase in vasopressin biosynthesis in cultures established from adult animals. Medium conditioned by fetal cerebral cortex, liver, or hypothalamic tissue from fetuses of less than 33 days gestation did not have this stimulatory effect.
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PMID:The hypothalamo-neurohypophysial complex in organ culture: effects of metabolic inhibitors, biologic and pharmacologic agents. 16 41

The lysosomes of hepatocytes increase in numbers and size during acute cell injury in vivo. To elucidate the mechanism of this change, we have studied in vitro the response of the autophagic lysosomal system to several physiologic mediators of autophagy, and to agents known to induce injury and/or the accumulation of lysosomes in vivo. To this end, monolayer cultures of rat hepatocytes were labeled with [14C]leucine to measure hepatocyte protein degradation; ultrastructural analyses were carried out to measure the volume fraction of lysosomes in the hepatocytes. Dibutyryl cyclic AMP increased protein degradation in the hepatocytes either in the presence or absence of serum and insulin. Deprivation of serum and insulin also increased hepatocyte protein degradation. Morphometric analysis indicated parallel increases in the volume fraction of lysosomes in the hepatocytes. The calcium ionophore ionomycin (5 microM), in the presence of 1.3 mM extracellular calcium, increased protein degradation (but not the volume fraction of lysosomes), and this increase was abolished by the addition of ethyleneglycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid. On the other hand, vasopressin (5 nM) caused an increase in protein degradation coupled with an increase in volume fraction of lysosomes. The microtubule depolymerizer vinblastine decreased protein degradation. The microtubule stabilizer taxol did not prevent the inhibitory effects caused by vinblastine. Parallel decreases in the lysosomal compartment were found in the hepatocytes exposed to vinblastine or taxol. Dimethylnitrosamine inhibited protein degradation as well as decreased the volume fraction of lysosomes. Finally, carbon tetrachloride also decreased protein degradation. These data indicate that in physiologic conditions, increases in numbers of hepatocyte lysosomes reflect increased sequestration and degradation of cytoplasmic proteins in response to changes in the levels of hormones, serum factors and nutrients as well as cyclic AMP. The induction of acute cell injury in vitro by calcium ionophore, microtubule active agents, and hepatotoxins inhibits lysosomal proteolysis and causes a decrease in the volume fraction of lysosomes. We conclude that the increase in lysosomal size and numbers occurring in acutely injured hepatocytes in vivo is induced primarily by altered levels of nutritional and hormonal regulators of lysosomal protein degradation.
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PMID:Response of autophagic protein degradation to physiologic and pathologic stimuli in rat hepatocyte monolayer cultures. 283 7

The present study was performed to investigate the potential of human medullary thyroid carcinoma (MTC) cells to secrete ACTH, beta-LPH/beta-EP. In addition, these studies might shed further light on the possible synthesis of a common precursor molecule for calcitonin (CT), ACTH and beta-LPH/beta-EP. MTC tissue was obtained from 10 patients (6 familial, 4 sporadic) without clinical and biochemical signs of Cushing's syndrome. Single cell suspensions were cultured for 1 to 2 weeks. Mean basal release of beta-LPH/beta-EP was 0.76 +/- 0.29 (SE) ng/10(6) cells/4 h (n = 10). Dibutyryl cyclic AMP (3 mM) stimulated beta-EP release significantly in 3 out of 7 cultures, while Ca2+ (2 mM) had no effect at all. The effects of the physiological regulators of pituitary ACTH and beta-LPH/beta-EP secretion, synthetic corticotropin-releasing factor (CRF-41) and vasopressin (LVP) were also studied in these MTC cell cultures. LVP (100 nM) had no effect on beta-EP release from MTC cells of all 8 cultures investigated. CRF-41 (10 nM) stimulated beta-EP release from 5 cultures and was without effect on 4. Maximal stimulation was noticed with 10 nM, while the effect of 100 nM CRF-41 was lower or absent. Stimulation was most outspoken in 3 cultures of familial MTC, whereas in 2 cultures of sporadic MTC CRF-41 stimulated beta-EP release marginally only after a 24 h incubation. LVP and/or CRF-41 stimulated CT release significantly in 3 cultures from sporadic MTC, while in these cultures the effect of CRF-41 on beta-EP release was either very small or absent.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Secretion of adrenocorticotropin, beta-endorphin and calcitonin by cultured medullary thyroid carcinoma cells. Effects of synthetic corticotropin-releasing factor and lysine vasopressin. 302 Aug 52

In in vitro cultures of liver from Ambystoma mexicanum glycogenolysis was stimulated by adrenaline, glucagon, and vasopressin in a dose-dependent manner. Maximum activity was seen at 10(-6) M hormone while 10(-9) M was without effect. Dibutyryl cyclic AMP (10(-3) M) stimulated glycogenolysis maximally although 10(-5) M had no effect. The glucose release brought about by adrenaline was blocked by the beta-adrenergic antagonist propranolol but not by prazosin or yohimbine which are alpha 1- and alpha 2-adrenergic antagonists. Cyclic AMP concentrations in liver were elevated within 1 min of administration of adrenaline and remained elevated for at least 60 min. Phosphorylase a activity was elevated 10 min after addition of adrenaline and remained elevated for at least 6 hr. The rise in hepatic cyclic AMP concentration and phosphorylase a activity was largely blocked by propranolol. These findings are consistent with adrenaline acting via a beta-adrenergic receptor in A. mexicanum. Glycogenolysis in A. mexicanum liver was stimulated by isoprenaline and phenylephrine and in each case the stimulation was reduced in the presence of propranolol but unaffected by phentolamine. High concentrations of methoxamine, a specific alpha 1-agonist, had no effect upon glycogenolysis. These findings suggest that alpha-adrenergic receptors play no role in regulation of glycogenolysis in A. mexicanum.
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PMID:Hormonal control of glycogenolysis and the mechanism of action of adrenaline in amphibian liver in vitro. 630 36

Brain slices of the guinea-pig hypothalamus were used to determine the effects of vasopressin on intracellular potentials in neurones of the supraoptic nucleus. Vasopressin (0.05-1 i.u./ml.) depolarized the membrane without apparent change in the input resistance and decreased the spontaneous firing rate. This action of vasopressin was retained in the medium containing 0 mM-Ca2+, 12 mM-Mg2+ and 0.3 mM-EGTA. Amplitude of the vasopressin-induced depolarization was voltage-independent. Ion-substitution experiments showed that the changes in [K+]o, [Cl-]o and [Ca2+]o had little effect upon the amplitude of vasopressin-induced depolarization, whereas the depletion of [Na+]o slightly reduced the amplitude. The vasopressin-induced depolarization was blocked at a temperature of 15 degrees C and by ouabain in a dose of 10(-4) M. Dibutyryl cyclic AMP (2 mM) produced electrophysiological effects similar to those seen with vasopressin, and actions of both agents were potentiated by either papaverine (10(-4) M) or theophylline (10(-2) M). Contents of cyclic AMP in tissues incubated with vasopressin were significantly higher than in cases of incubation with normal Krebs solution. We conclude that vasopressin directly modulates the activity of supraoptic neurones, possibly through activation of adenylate cyclase.
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PMID:The effects of vasopressin on electrical activity in the guinea-pig supraoptic nucleus in vitro. 630 38

Tryptophan uptake, hydroxylation, and decarboxylation in isolated synaptosomes were studied to assess how their properties may determine the rate of serotonin synthesis in the presynaptic nerve terminals of the brain. Simultaneous measurements of the rates of uptake, hydroxylation, and decarboxylation in the presence and absence of various inhibitors showed that tryptophan hydroxylase is rate-limiting for serotonin synthesis in this model system. There was significant direct decarboxylation of tryptophan to tryptamine. Measurement of tryptophan hydroxylase flux with varying internal concentrations of tryptophan allowed the determination of the Km of tryptophan hydroxylase in synaptosomes for tryptophan of 120 +/- 15 microM. Depolarisation of synaptosomes with veratridine caused both a reduction in the internal tryptophan concentration and an apparent activation of tryptophan hydroxylase. This activation did not occur in the absence of Ca2+ or in the presence of trifluoperazine. Synaptosomal serotonin synthesis and brain stem-soluble tryptophan hydroxylase were inhibited by low concentrations of noradrenaline or dopamine. Dibutyryl cyclic AMP, glucagon, insulin, and vasopressin were observed to have no effect on tryptophan uptake or hydroxylation in synaptosomes.
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PMID:Tryptophan uptake and hydroxylation in rat forebrain synaptosomes. 669 97

The effect of modulation of the rate of glycogenolysis on the availability of 5-phosphoribosyl-1-pyrophosphate (PRPP) was investigated in rat hepatocyte cultures. Dibutyryl cyclic AMP (dbcAMP), forskolin and glucagon, activating glycogen phosphorylase through activation of protein kinase A (PKA), were found to raise PRPP availability by 44%-56%. Arg-vasopressin and phenylephrine, activating glycogen phosphorylase through the phosphoinositide cascade, did not affect PRPP availability. dbcAMP, but not phenylephrine, increased the degradation of pre labeled glycogen by 57%. Caffeine and CP-91149, inhibitors of glycogen phosphorylase, decreased PRPP availability by 33% and 43%, respectively. The finding that induction of glycogenolysis enhances, and inhibition of glycogenolysis decelerates PRPP generation suggests that glycogenolysis is a major contributor to PRPP generation in liver tissue in the basal (postabsorptive) state.
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PMID:Modulation of glycogen phosphorylase activity affects 5-phosphoribosyl-1-pyrophosphate availability in rat hepatocyte cultures. 1557 Dec 36