Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activity of the Na pump was judged by Na extrusion in epithelial cells loaded with Na by a previous incubation in K-free solutions in the cold. Oxytocin significantly stimulated Na extrusion either at normal (3.5 mM) or low (0.25 mM) K in the medium. It was stimulated as well by cyclic AMP. Maximal concentrations of either agent caused about the same degree of stimulation. Addition of ouabain or removal of K prevented the action of both agents, but amiloride showed no effect at all. These results strongly suggest that, a) neurohypophyseal hormones not only increase Na entry across the mucosal barrier of the epithelium but they also stimulate the serosal Na pump, b) cyclic AMP not only mediates the action of neurohypophyseal hormones on Na and water permeability of the mucosal barrier, but it also mediates the action of the hormones on the Na pump of the serosal barrier.
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PMID:Sodium pump stimulation by oxytocin and cyclic AMP in the isolated epithelium of the frog skin. 20 19

The specific binding of [125I]LH-RH to isolated plasma membranes of rat pituitaries was investigated. The binding process was found to be highly specific, temperature-dependent and saturable. The dissociation constant as caluclated by three different methods was approximately 1.3 . 10(-8) M, indicating a single type of binding sites. Maximal binding capacity was 1 . 10(-12 moles/mg protein (= 2 ng LH-RH/pituitary gland), and the number of binding sites was calculated to be 6 . 10(11) per mg membrane protein (=1 . 10(10) binding sites/pituitary gland). When diluted with ice-cold buffer the dissociation of specifically bound LH-RH occurred very rapidly (half-life 3.17 min) with a rate constant of 0.219 min-1. The dissociation process followed first-order kinetics. Specificity of binding was demonstrated by dose-dependent competition of unlabelled LH-RH, the highly potent analogue D-glutamine-(cyclohexyl)6-LH-RH-nonapeptide-ethylamide and the fragment of an analogue (6-D-Ser(TBu))-LH-RH-(3-9)-heptapeptide-ethylamide with the binding [125I]LH-RH, while angiotensin I, II, oxytocin and bacitracin did not compete. The affinities of LH-RH and the analogue to the binding sites of the pituitary plasma membranes were not consistent with the respective biological activities.
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PMID:Interaction of [125I]LH-RH and other oligopeptides with plasma membranes of rat anterior pituitaries. 22 10

Biosynthesis of peptides in vitro in male rat hypothalamic fragments wasinvestigated by incubating the tissue with 14C-labelled leucine, proline and glycine. Depending on the amino acid used, 4 or 6 labelled peptides were extracted from the tissue fragments with organic solvent mixture. The incorporation of the label into peptides was time dependent. LH-RH and oxytocin thus synthesized were identified by thin layer chromatography and high voltage electrophoresis using cold LH-RH and oxytocin as standards.
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PMID:Incorporation of 14C-amino acids into rat hypothalamus in vitro. 32 95

A new hypothesis is presented for the first time to explain the etiology of osteoporosis. Prostaglandins (E2 and F2 alpha) at precise concentrations, have been observed to be involved in bone formation. A close association exists between levels of prostaglandins (E2 and F2 alpha) demonstrated in the neonatal mouse leading to bone formation, with estimated prostaglandins (E2 and F2 alpha) concentrations reported in man. Several hormones (vasopressin, oxytocin, luteinizing hormone, follicle-stimulating hormone, cortisol, estradiol, and testosterone) can indirectly affect prostaglandin formation leading to reduced bone formation. The association between these hormones and prostaglandins (E2 and F2 alpha) explains the physiological mechanism whereby estradiol can be effective for the treatment of osteoporosis. This association also explains the etiology of lumbar spondylitis/spondylodynia, reasons for complaints of increased pain in wet cold weather among arthritics and a multitude of other events. Mechanisms related to this interaction between various hormones and the effect of prostaglandins (E2 and F2 alpha) on bone formation are discussed.
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PMID:New clues into the etiology of osteoporosis: the effects of prostaglandins (E2 and F2 alpha) on bone. 132 11

Glutamate microinjection (1 M, 250 nl) into the hypothalamic supraoptic nucleus (SON) stimulated heat production in brown adipose tissue (BAT) and caused a rapid and sustained increase in interscapular BAT and core temperatures in urethane-anaesthetized rats. This effect was blocked by intraperitoneal pretreatment with a sympathetic ganglionic blocker, chlorisondamine chloride (2.5 mg/kg), or a beta-adrenergic receptor blocker, propranolol (2.5 mg/kg), but not by prior hypophysectomy or intracerebroventricular pretreatment with specific receptor blockers to vasopressin (d(CH2)5[Tyr(Me)2]AVP, 5 micrograms) or oxytocin (d(CH2(5)[Tyr(Me)2,Thr4,Tyr-NH2(9)]OVT, 5 micrograms). The results demonstrate that stimulation of SON cells with glutamate elicits a non-vasopressinergic/non-oxytocinergic neural signal that can bring about a sympathetically-mediated increase in BAT thermogenesis. Heat production in BAT is an important mechanism of thermal protection during cold stimulation, and there is evidence that osmotic stimulation can influence thermoregulation. SON neurons play a major role in osmoregulation via release of the peptide hormones vasopressin and oxytocin. The present results suggest the possibility that apart from releasing peptide hormones for osmoregulation, SON neurons might be involved in mediating the effect of osmotic stimulation on thermoregulatory responses involved in thermal adaptation.
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PMID:Activation of brown adipose tissue thermogenesis by chemical stimulation of the hypothalamic supraoptic nucleus. 168 14

Cold exposure increases blood levels of TSH and thyroid hormones by stimulating the secretion of TRH from the median eminence. Thyroid hormones reduce TRH release and cellular levels of TRH mRNA. Using quantitative in situ hybridization to measure changes in cellular levels of various neuropeptide mRNAs, the present studies demonstrate that cold exposure also increases cellular levels of TRH mRNA in neurons of the paraventricular nucleus (PVN), supporting the concept that TRH mRNA levels are reflective of TRH secretion in these neurons. The effect of cold appeared to be specific for TRH expression in the PVN, because cold exposure did not influence cellular levels of TRH in the reticular thalamic nucleus or beta-actin and oxytocin mRNAs in the PVN. Cellular levels of mRNA encoding CRH were elevated by cold exposure. This latter observation is predictable based on the cold-induced activation of the hypothalamic-pituitary-adrenal axis. There was a 24-h rhythm and a time of day difference in the effect of cold on TRH mRNA levels in the PVN. Time of day differences in the effect of cold on CRH mRNA levels were not apparent. Cold exposure appeared to elevate TRH mRNA levels in all neurons of the PVN, indicating that the neurally mediated effect of cold on TRH expression can override the inhibitory effects of circulating T3 within the same neuronal population.
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PMID:Cold exposure elevates cellular levels of messenger ribonucleic acid encoding thyrotropin-releasing hormone in paraventricular nucleus despite elevated levels of thyroid hormones. 212 45

Central neural activity was assessed by measuring relative cytochrome oxidase (CO) activity in the ventromedial nucleus (VMN; thermogenesis regulation), the parvocellular paraventricular nucleus (PVN; feeding regulation), and the magnocellular PVN (secretion of vasopressin and oxytocin) in 10 age-matched pairs of 39- to 42-day-old Zucker rats. When obese (fa/fa) were compared to lean (Fa/Fa) rats, relative CO activity was significantly lower (approximately 10 percent) in the VMN and parvocellular PVN, but not in the magnocellular PVN. Cell diameters did not differ. To determine if there were corresponding differences in levels or release of hypothalamic monoamines, we compared 7 pairs of 90- to 94-day-old lean (Fa/?) and obese (fa/fa) rats at rest and after 2 h of 9 degrees C. Tissue punches from frozen PVN, VMN, and preoptic area (the latter being a site of thermosensitive units modulating VMN output) were assayed. In obese vs. lean noncold-exposed rats, we observed lower concentrations of: 5-hydroxyindoleacetic acid (5HIAA; metabolite of serotonin, 5HT) in the VMN; 3-methoxy-4-hydroxyphenylglycol (MHPG; metabolite of norepinephrine, NE) and NE + MHPG (index of total NE) in the preoptic area; and 3,4-dihydroxyphenylacetic acid (DOPAC; metabolite of dopamine, DA) in the PVN. Additionally, in the VMN, cold exposure resulted in: elevated concentrations of MHPG and MHPG + NE in both lean and obese rats; elevated concentrations of 5HT, 5HIAA, and 5HT + 5HIAA in obese rats, with no significant changes in these variables in lean animals; decreased ratio of 5HIAA/5HT in obese rats and increased ratio in leans. In the preoptic region, cold exposure led to increased concentrations of MHPG, NE + MHPG, 5HT, and 5HT + 5HIAA in obese but not lean rats. In the PVN, 5HT concentrations were increased in cold-exposed obese but not lean rats. Our data support the hypothesis that neuronal activity in obese rats differs from that of lean rats at rest and during cold exposure and suggest that several monoamine systems play a role in such differences.
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PMID:Neuronal activity in hypothalamic nuclei of obese and lean Zucker rats. 217 50

The presence of the human placental enzyme, oxytocinase, in blood samples taken during pregnancy causes major methological problems in the radioimmunoassay for plasma oxytocin. Inadequate inhibition of the enzyme activity may lead to spuriously high or low values of plasma oxytocin. This study systematically investigates a variety of enzyme inhibitors. The optimum inhibitory system was obtained by the addition of 10 microliters of cold 125 mmol/l 1.10 phenanthrolene and 1 mol/l EDTA per ml of whole blood into the syringe. Complete enzyme inhibition was maintained for up to 60 min, during which time the lithium heparinized plasma samples were extracted by the Florisil method. Following extraction there was no enzyme activity in the extract residue. Concentrations of phenanthrolene and EDTA necessary to eliminate enzyme activity were 50- and 10-fold greater, respectively, than in any previously reported method. Recovery of synthetic oxytocin added to pregnancy plasma with inhibitors was 80% or higher, over the concentration range 1-100 pmol/l. Extract residue could be stored at -20 degrees C for up to 7 weeks. Dilutions of pregnancy plasma extracts ran parallel to the oxytocin standard curve. Studies on plasma concentrations of oxytocin (OT) during the first stage of labour in 6 patients showed that 3 had pulsatile plasma OT, peak values ranging from 4-10 pmol/l in phase with uterine concentrations, but 2 who had regular uterine activity had no episodic changes in plasma OT. One patient with hypocontractile labour had low non-fluctuating plasma OT.
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PMID:Evaluation of enzyme inhibitors of pregnancy associated oxytocinase: application to the measurement of plasma immunoreactive oxytocin during human labour. 243 27

Sixty-six women with stagnant blood and cold dysmenorrhea were treated with Zhuyu Wengong Decoction (ZWD). The results showed that 47 of them were cured, 13 improved, the total effective rate was 90.9%. Before treatment, the value of amplitude and the volume of blood flow in the left pelvic cavity with blood flow graph was very lower in the dysmenorrhea patients than those in the normal women (P less than 0.01), while the number of amplitude difference between the left and the right pelvic cavity being over 30% and of abnormal wave was higher in the patients than that in the normal women (P less than 0.01). After treatment, the value of amplitude and the volume of blood flow in the left pelvic cavity had a marked increase (P less than 0.01). These data suggested that blood circulation in the pelvic cavity took a turn for the better after the treatment. The results in animal experiment also showed that ZWD had strongly suppressive effect on the automatic action of uterine muscle of rats in vitro and of rabbits in vivo. The suppressive rates were 30.75% and 20% respectively, and the contractive range was at a lower level. The decoction also had strong suppressive effect on the contract induced by MPGF2 alpha, suppressive rate decreased to 24.4% and 34.75% respectively in contrast to the group which patients had not taken this decoction. The results in this study also proved that ZWD could improve the reduction of blood flow volume induced by MPGF2 alpha and had analgesic effect on dysmenorrhea model of rats induced by oxytocin.
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PMID:[Cold dysmenorrhea with blood stagnation treated with zhuyu wengong decoction]. 259 45

The effects of modified adrenergic transmission on the bioassayed storage of vasopressin and oxytocin in the hypothalamus and neurohypophysis under conditions of stress (cold or immobilization), disturbed water balance and pinealectomy are reviewed. Alpha-adrenergic mechanisms seem to be included in the response of vasopressinergic and oxytocinergic neurones to stress; on the other hand, impulses of osmoreceptor origin are of importance in regulatory processes affecting the functional response of these neurones to altered alpha-adrenergic transmission and also to melatonin. The beta-adrenergic (and, to some extent, also the alpha-adrenergic) transmission is probably involved in the neural mechanisms of the pineal-neurohypophysial relationship. Furthermore, a possible regulatory role of cholecystokinin in water metabolism and release of neurohypophysial hormones is suggested.
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PMID:Studies on the vasopressin and oxytocin storage in the hypothalamus and neurohypophysis. 284 Jul 99


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