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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A variety of molecular techniques were used to search human and baboon gonadal tissues for evidence of transcription of the genes for the peptide hormones oxytocin and vasopressin. Only a highly sensitive assay based on a modification of the polymerase chain reaction succeeded in detecting mRNA copies of the oxytocin gene in both human and baboon corpus luteum. Vasopressin gene transcription was not detected in human testis and corpus luteum and was found only once in four different experiments in baboon corpus luteum. Evidence for oxytocin gene transcription in the human testis was found in three of five experiments. The method employed and subsequent sequence analysis of the polymerase products verified the presence of oxytocin mRNA with normal hypothalamic-type exonic structure in primate corpus luteum. Nevertheless, the very low levels of mRNA present are unlikely to support other than local functions for the encoded nonapeptide hormones.
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PMID:Expression of the oxytocin and vasopressin genes in human and baboon gonadal tissues. 224 37

Cervical tissue strips from nonpregnant women and women in early and term pregnancy were used to study spontaneous contractile activity and the effects of oxytocin and vasopressin in vitro. Oxytocin stimulated contractions in strips from all groups of patients except for those from five term pregnant women, in which an inhibitory effect was observed at a high concentration. Vasopressin had a stimulatory effect in all groups of patients. These neurohypophyseal hormones may interact with the effect of other hormones in their regulatory influence on cervical contractility, and this interaction might be important in cervical dilatation during labor as well as in the pathophysiology of dysmenorrhea.
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PMID:Influence of neurohypophyseal hormones on human cervical smooth muscle contractility in vitro. 230 Mar 51

Explants of the hypothalamoneurohypophysial system (HNS) from rats were maintained in perifusion culture and exposed to 15-18 mosmol/kgH2O changes in the osmolality of the culture medium achieved by increasing or decreasing the NaCl concentration. The rate of change in osmolality was either 0.14 +/- 0.01 mosmol/min (2%/h), 0.27 +/- 0.02 mosmol/min (5%/h), or 1.7 +/- 0.2 mosmol/min (30%/h). Vasopressin (VP) and oxytocin (OT) release into the culture medium was determined. Increased VP release was detected after all three rates of increase, but the peak response occurred sooner and in response to a smaller increment in osmolality during the 5% rate of increase compared with the 2% rate of increase. Peak VP release occurred during the first 10 min of the 30% pulse and was significantly greater than the response to the 2 and 5% rates (P less than 0.05). The increase in VP release was sustained throughout the 3 h of hypertonicity during the 2% pulse, but not during the 5 and 30% osmotic pulses. A significant decrease in VP release was observed on returning the osmolality to basal at both the 2 and 5% rate, but this inhibition was followed by a rebound in VP release that started during the decrease in osmolality and significantly exceeded basal VP release. A significant inhibition of VP release also was observed when explants were exposed to hypotonic pulses at the 2 and 5% rate. At both rates, the inhibition of VP release corresponded to a 5- to 7-mosmol/kgH2O decrease in osmolality.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Osmotic regulation of vasopressin and oxytocin release is rate sensitive in hypothalamoneurohypophysial explants. 230 38

Pantethine, a cysteamine precursor, depletes somatostatin in the cerebral cortex and hypothalamus and prolactin in the anterior pituitary and hypothalamus. This study investigated the effect of pantethine on oxytocin and arginine vasopressin content in the posterior pituitary and hypothalamus. Male Long-Evans rats were injected intraperitoneally with escalating doses of pantethine (i.e., 146.7 mg, 293.4 mg and 586.6 mg/100 gm body weight). Hormone content was determined by radioimmunoassay. Three hours after pantethine treatment, the oxytocin content in the posterior pituitary and the hypothalamus was markedly reduced with all doses of the drug. Vasopressin content in the posterior pituitary and hypothalamus was decreased but to a lesser extent than oxytocin and only with the highest dose of pantethine. Pantethine may act to reduce oxytocin and vasopressin content through intracellular conversion to cysteamine. The exact mechanism of action of pantethine on oxytocin and vasopressin remains to be elucidated.
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PMID:Changes in oxytocin and vasopressin content in posterior pituitary and hypothalamus following pantethine treatment. 240 77

The 3T3-F442A mouse fibroblast cell line, triggered by factors present in fetal calf serum (FCS), converts either spontaneously or, in the simultaneous presence of FCS and insulin, at an accelerated rate into cells exhibiting the adipocyte phenotype. The effects of the neurohypophysial hormones in differentiated cells on glucose metabolism (glucose oxidation and lipogenesis) were compared with the stimulatory actions of insulin, which had its most pronounced effects in cells differentiated spontaneously with FCS in the absence of insulin. The differentiated 3T3-F442A cells were sensitive to physiological levels of insulin and exhibited manyfold increases in glucose metabolism in response to it. This result demonstrated that these cultured cells respond to insulin, in a manner analogous to freshly isolated adipocytes. In contrast to its insulin-like effects in isolated epididymal adipocytes, oxytocin was not reproducibly able to stimulate glucose metabolism in differentiated 3T3-F442A cells. Vasopressin was similarly inactive. In contrast, both oxytocin and vasopressin blocked adipocyte conversion triggered by FCS, either in the presence or absence of insulin; vasopressin was more potent than oxytocin, indicating that a vasopressin receptor was responsible for the observed inhibition of differentiation. Our work suggests that vasopressin could potentially play a role in the regulation of the adipocyte differentiation process.
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PMID:Effects of oxytocin and vasopressin on the preadipocyte 3T3-F442A cell line. 243 40

Voltage-dependent Ca2+ channels of the aortic cell line A7r5 were studied using 45Ca2+ flux experiments. Ca2+ channels which have been studied belong to the L-type and are very sensitive to inhibitors and activators in the 1,4-dihydropyridine series as well as to (-)desmethoxyverapamil and d-cis-diltiazem. L-type Ca2+ channels in these smooth muscle cells are not affected by cyclic 8-bromo-AMP and dibutyryl cyclic AMP. However, the activity of these channels is strongly depressed after treatment with diacylglycerols (1-oleyl 2-acetylglycerol and 1,2-dioctanoylglycerol). Phorbol esters, which like diacylglycerols are well-known activators of protein kinase C (the Ca2+- and phospholipid-dependent enzyme), inhibit 70% of Ca2+ channel activity (K0.5 = 25 nM for phorbol 12-myristate 13-acetate and K0.5 = 200 nM for phorbol 12,13-dibutyrate). Phorbol esters that are inactive on kinase C are without effect on Ca2+ channel activity. [Arg8]Vasopressin and bombesin, two peptides that are well known for their action on polyphosphoinositide metabolism, inhibit Ca2+ channel activity to the same extent as active phorbol esters (65-70%). Oxytocin has the same type of effect presumably by acting at the V1-receptor. Both effects of [Arg8]vasopressin and oxytocin are suppressed by [1-(beta-mercapto-beta,beta-diethylpropionic acid)4-valine]arginine vasopressin, a specific vasopressin antagonist at the V1-receptor.
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PMID:Regulation of calcium channels in aortic muscle cells by protein kinase C activators (diacylglycerol and phorbol esters) and by peptides (vasopressin and bombesin) that stimulate phosphoinositide breakdown. 243 72

Vasopressin and oxytocin are peptide hormones which act on a variety of target organs, including kidney, smooth muscle, liver, and anterior pituitary. During the last decade, it has become apparent that these two neuropeptides may in addition act as neurotransmitters. We review a number of arguments which support this conjecture: 1) Vasopressin and oxytocin are not only synthesized in hypothalamoneurohypophysial neurones, but also in other--hypothalamic and extrahypothalamic--cell bodies whose axon projects to the limbic system, the brainstem and the spinal cord. 2) Vasopressin and oxytocin can be shed from central axons by the same secretory mechanism as are classical neurotransmitters. 3) Specific binding sites having a high affinity for vasopressin and/or oxytocin are present in the central nervous system. These binding sites represent functional receptors, because agonist binding leads to an increase in membrane phosphatidylinositol turnover. 4) Receptors, or at least part of them, are localized on neurones, since application of exogenous vasopressin and oxytocin alters the rate of firing of single neurones present in regions where binding sites have been detected autoradiographically. 5) Central vasopressin and oxytocin may play a role in brain functions, since in situ injection of antagonists interferes with physiological regulations.
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PMID:[Vasopressin and oxytocin as neuromediators]. 247 48

Binding of [3H]arginine vasopressin (AVP) and [3H]oxytocin to primary monolayer cultures of bovine adrenal chromaffin cells was time-dependent, and the binding sites for each peptide were specific and saturable. Studies with the V1 AVP antagonist d(CH2)5Tyr(Me)2-AVP, the V2 agonist 1-deamino-8-D-AVP and the V2 antagonist d(CH2)5D-Leu2,Val4-AVP indicated that the AVP receptor was V1 in specificity. Scatchard plots showed that each ligand interacted with a single high-affinity, low-capacity binding site: oxytocin dissociation constant (Kd) 0.29 +/- 0.02 nmol/l, maximum binding capacity (Bmax) 7.6 +/- 0.2 fmol/10(6) cells (or 4500 +/- 102 sites/cell) (n = 3); AVP Kd 0.09 +/- 0.02 nmol/l, Bmax 5.1 +/- 0.63 fmol/10(6) cells (or 3050 +/- 318 sites/cell) (n = 3). Although forskolin in concentrations from 1 nmol/l to 1 mmol/l stimulated cyclic AMP (cAMP) production in isolated chromaffin cells, this did not result in detectable catecholamine release. Neither AVP nor oxytocin in concentrations between 10 pmol/l and 10 mumols/l stimulated cAMP production in these cells. Vasopressin in concentrations as low as 10 pmol/l stimulated a sixfold increase in total inositol phosphates; the dose-response curve was triphasic. Oxytocin had little effect on total inositol phosphate accumulation at low concentrations, but concentrations above micromolar stimulated total inositol phosphate production approximately fourfold. There was no measurable release of catecholamines in response to either peptide. The physiological consequences of these AVP-induced changes in inositol phosphate concentrations remain to be elucidated.
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PMID:The interaction of arginine vasopressin and oxytocin with bovine adrenal medulla cells. 254 Dec 18

Vasopressin (VP) and oxytocin (OT) binding sites were localized and quantified in the developing brain of the Wistar, heterozygous (Het) and homozygous (Hom) VP-deficient Brattleboro rat using an autoradiographical technique. VP binding sites could be demonstrated from prenatal day 20 onwards in the septum and in the lateral reticular nucleus. Between this and postnatal day 15, VP binding sites appeared in all other brain areas known to contain VP binding sites in adulthood. In the caudate putamen the regional distribution of VP binding changed during development, while in some areas, for instance, the dorsal hippocampus and post cingulate cortex, the concentration of binding sites increased early but decreased with age. Comparison of VP binding between Het and Hom rats showed significant differences in the lateral reticular nucleus during development. Moreover, at postnatal day 15 there was more VP binding in the anterior commissural and suprachiasmatic nucleus and less in the central amygdala, dorsal hippocampus and post cingulate cortex of the Hom rat. This study shows, for the first time, OT binding sites in the developing rat brain. There is a considerable overlap with VP binding in the brain, sometimes with the same developmental pattern, e.g. in the anterior olfactory nucleus and caudate putamen and sometimes with a later appearance, e.g. in the central amygdala and thalamic nuclei. However most areas with VP binding sites did not show OT binding. In some areas only OT binding sites were present, for instance in the islands of Calleja and ventromedial hypothalamus. Similar to some areas with VP binding, OT binding decreased between postnatal day 5 and 15 in the dorsal hippocampus and even completely disappeared in the parietal cortex. The existence of VP binding sites in the Hom rat, together with the only occasional relationship between the previously described ontogeny of VP and OT innervation of the brain and the presently described developmental course of binding sites, indicates that the early expression of binding sites is not initiated by endogenous ligand. However, the setting of the number of VP binding sites has probably been affected by the VP deficiency of the Hom Brattleboro rat.
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PMID:Ontogeny of vasopressin and oxytocin binding sites in the brain of Wistar and Brattleboro rats as demonstrated by lightmicroscopical autoradiography. 255 39

1. This study utilized retrograde anatomical tracer techniques and in vivo extracellular electrophysiological studies to examine caudal ventrolateral and dorsomedial medulla afferents to supraoptic nucleus neurosecretory neurones in male Long-Evans rats. 2. In one series of experiments, pentobarbitone-anaesthetized animals were subjected to ventral exposure of the hypothalamus and rhodamine-tagged latex microspheres (0.05-0.2 microliter) were injected into one supraoptic nucleus. Following perfusion with paraformaldehyde-glutaraldehyde 18-24 h later, cell counts were obtained of rhodamine- and/or catecholamine-labelled neurones in the caudal ventrolateral and dorsomedial medulla both ipsi- and contralateral to the injection site. 3. In the caudal ventrolateral medulla, each injection labelled fewer than 15% of the catecholaminergic neurones; with small injections, most (68-100%) of the rhodamine-labelled neurones also displayed catecholamine histofluorescence. In the caudal nucleus tractus solitarii, one-half to one-third as many rhodamine-labelled cells were observed, but a higher percentage (13-100%) of these were non-catecholaminergic. 4. Extracellular recordings were obtained from antidromically identified supraoptic neurones classified as vasopressin (n = 106) or oxytocin (n = 26) secreting. Single cathodal pulses (0.2 ms duration, 0.02-0.08 mA) applied in the caudal half of the ipsilateral nucleus tractus solitarii evoked a transient (30-50 ms) activation of 63% of both vasopressin- and oxytocin-secreting neurones. Mean latencies (+/- S.E.M.) for vasopressin and oxytocin cells were 49.8 +/- 1.0 and 46.5 +/- 2.4 ms respectively; these were not significantly different. Similar responses were noted to contralateral stimuli applied to four vasopressin and two oxytocin cells. 5. Vasopressin neurones activated by caudal nucleus tractus solitarii stimulation displayed similar patterns of response to stimulation in the caudal ventrolateral medulla. However, latencies from the nucleus solitarius (mean 47.6 +/- 1.4 ms; n = 59) were significantly longer (P less than 0.05) than from the ventrolateral medulla (41.5 +/- 2.0 ms; n = 17). In eight out of eleven vasopressin neurones tested, interruption of synaptic transmission through the ventrolateral medulla reduced or abolished the caudal nucleus tractus solitarii-evoked excitation but had no effect on their response to baroreceptor activation. This manoeuvre affected zero out of five oxytocin cells similarly excited by nucleus solitarius stimulation. 6. These observations indicate that visceral input mediated through the nucleus tractus solitarii is transmitted differentially to supraoptic vasopressin- and oxytocin-secreting neurones.
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PMID:Dorsomedial medulla stimulation activates rat supraoptic oxytocin and vasopressin neurones through different pathways. 262 94


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