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

Recent data on various environmental stressors and blood hormone patterns are presented for lactating cattle. Known stressor effects of such factors as environmental temperature, air pollution, and noise on the plasma thyroxine, growth hormone, cortisol, prolactin, progesterone, luteinzing hormone, epinephrine, and norepinephrine of lactating cattle are discussed. Information on stressor effects is lacking on glucagon, insulin, vasopressin, calcitonin, oxytocin, thyrotrophic hormone, follicle stimulating hormone, melatonin, parathyroid hormone, and estrogens in the lactating cow. The importance of evaluating both the effect of environmental stressor and of production or lactation intensity is emphasized in the overall interpretation of changes in hormone of plasma. The short and long term environmental heat effects on thyroxine, cortisol, and growth hormone are clear with initial increased due to acute stressors and a decline of amounts in plasma after prolonged exposure to stressors. The relationship of amounts in plasma of these hormones to milk production appears to be related directly for cortisol, growth hormone, and prolactin with an inverse relationship with thyroxine. Epinephrine and norepinephrine seem to be elevated with prolonged environmental heat stress. However, the influence of intensity of lactation has not been measured. Hormones in plasma as they relate to stressor effects and milk production are important as potential indicators of the physiological state of a cow and reflect the physiological compensations a cow undergoes at various lactation intensities and/or stress exposure.
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PMID:Effects of environmental and other stressors on blood hormone patterns in lactating animals. 98 81

Interactions of several proteins with glutathione-insulin transhydrogenase (GIT) have been investigated by determining their ability to inhibit degradation of 125I-labeled insulin catalyzed by GIT. The inhibition by every insulin analog (des-Asn-des-Ala-pork insulin, desoctapeptide-pork insulin, des-Ala-pork insulin, pork insulin, proinsulin, and guinea pig insulin) was competitive vs. competitive vs. insulin indicating that they function as alternate substrates. The insulin analogs with the least hormonal activity showed the highest potency as inhigitors of insulin degradation. Whereas native ribonuclease and lysozyme showed little or no inhibition, their scrambled forms (i.e. reduced and randomly reoxidized) showed competitive inhibition with a potency greater than that of insulin. These results suggest that the conformation of the substrate or inhibitor is probably the major factor in determining the specificity for (or binding to) the enzyme. Studies withother peptide hormones showed competitive inhibition with vasopressin and oxytocin and noncompetitive inhibition with glycagon. The inhibition with growth hormone could be either competitive or noncompetitive. The inhibition by glucagon and growth hormone (physiologic antagonists of insulin) could serve as a control mechanism to modulate the activity of enzyme. The following showed very little or no inhibition; the native and scrambled form of pepsinogen, trypsin inhibitor of beef pancreas and of lima bean, C-peptide of pork proinsulin, and heptapeptide (B23-B29) of insulin.
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PMID:Interaction of insulin analogs, glucagon, growth hormone, vasopressin, oxytocin, and scrambled forms of ribonuclease and lysozyme with glytathione-insulin transhydrogenase (thiol: protein-disulfide oxidoreductase): dependence upon conformation. 117 Aug 77

Infusion of oxytocin (OT) into normal dogs, in doses which produced plasma levels of OT in the physiological range, has been shown to increase plasma levels of glucose, insulin and glucagon and increase rates of glucose production and uptake. This study sought to determine whether there was a correlation between these metabolic effects and the oxytocic potency of four less potent oxytocic analogues when infused into normal dogs. The rank order of oxytocic potency of all 4 correlated well with the rise in plasma glucose levels, and in 3 of the 4 with the rise in plasma insulin levels. An antagonist of the oxytocic effect of OT suppressed the usual OT-induced rise in plasma glucose, insulin and glucagon as well as the increased glucose production and uptake. Arginine vasopressin (AVP) infusion, which by itself did not produce any metabolic effects, blocked completely the effects of OT infusion to raise plasma glucose and insulin levels and increase glucose production and uptake. The data suggest that the metabolic effects of OT in the dog are mediated by OT receptors that are similar to those producing the oxytocic effects. Whether the inhibition by AVP of the metabolic and hormonal effects of OT occurs at the receptor or post receptor level or via other mechanisms remains to be determined.
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PMID:The metabolic effects of oxytocin are mediated by a uterine type of receptor and are inhibited by oxytocin antagonist and by arginine vasopressin in the dog. 131 Jul 90

There is a great variation in body weight loss during lactation among primiparous sows fed a standard diet that is adjusted based on the number of piglets nursed and the maintenance requirements. Energy and protein catabolism is more pronounced during the first 1 to 3 weeks of lactation and sows with low weight loss recover earlier from their negative energy balance during lactation than sows with high weight loss. Using continuous blood collection a decrease in plasma levels of oxytocin, prolactin, and insulin, and an increase in plasma levels and no of LH pulses during lactation were demonstrated. Prolactin levels gradually increased in response to each suckling while only 40-50% of recorded sucklings induced a significant rise in plasma oxytocin. Following a 24-h fast during lactation, levels of prolactin were very low but increased rapidly after refeeding. Even plasma levels of insulin and glucose decreased to very low levels during fasting, but the release of LH was similar before and after refeeding. Weaning resulted in decrease in plasma levels of prolactin and increase in plasma levels and no. of LH pulses. Plasma levels of cortisol showed a diurnal pattern of change which disappeared on the day of weaning. In response to weaning plasma levels of glucagon and gastrin decreased, whereas insulin and somatostatin increased. At weaning sows with low weight loss during lactation had higher plasma insulin and lower plasma cortisol levels than sows with high weight loss, but no differences in levels or no. of LH pulses were observed between the two groups of sows.
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PMID:Metabolic and reproductive hormones during lactation and the post-weaning period in sows. 134 70

Oxytocin (OT) infusion in normal dogs increases plasma insulin and glucagon levels and increases rates of glucose production and uptake. The purpose of this study was to determine whether the effects of OT on glucose metabolism were direct or indirect. The studies were carried out in normal, unanesthetized dogs in which OT infusion was superimposed on infusion of either somatostatin, which suppresses insulin and glucagon secretion, or clonidine, which suppresses insulin secretion only. Infusion of 0.2 microgram/kg/min of somatostatin suppressed basal levels of plasma insulin and glucagon and inhibited the OT-induced rise of these hormones by about 60-80% of that seen with OT alone. The rates of glucose production and uptake by tissues, measured with [6-3H] glucose, were significantly lower than those seen with OT alone, and the rise in glucose clearance was completely inhibited. Clonidine (30 micrograms/kg, sc), given along with an insulin infusion to replace basal levels of insulin, completely prevented the OT-induced rise in plasma insulin and markedly reduced the glucose uptake seen with OT alone, but did not reduce the usual increase in plasma glucose and glucagon levels or glucose production. To determine whether the OT-induced rise in plasma insulin was in response to the concomitant increase in plasma glucose, similar plasma glucose levels were established in normal dogs by a continuous infusion of glucose and an OT infusion was superimposed. OT did not raise plasma glucose levels further, but plasma insulin levels were increased, indicating that OT can stimulate insulin secretion independently of the plasma glucose changes. Studies by others have shown that the addition of OT to pancreatic islets or intact pancreas can stimulate insulin and glucagon secretion, indicating a direct effect. Our studies agree with that and suggest that in vivo, OT raises plasma insulin levels, at least in part, through a direct action on the pancreas. These studies also show that OT increases glucose production by increasing glucagon secretion and, in addition, a direct effect of OT on glucose production is likely. The OT-induced increase in glucose uptake is mediated largely by increased insulin secretion.
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PMID:Role of insulin and glucagon in oxytocin effects on glucose metabolism. 134 36

1. Using an immunocytochemical procedure a wide range of immunoreactive vertebrate bioactive peptides (BAPs) has been found in hemocytes of Viviparus ater: bombesin, calcitonin, CCK-8, CCK-39, GH, glucagon, insulin, oxytocin, neurotensin, secretin, serotonin, somatostatin, substance P, vasopressin, and VIP. 2. No immunostaining was observed for antigastrin and antithyroglobulin antibodies. 3. The presence of BAP-like molecules in hemocytes suggests a correlation between hemocyte and APUD cells and is evidence of a relationship between the neuroendocrine and the immune systems.
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PMID:The presence of immunoreactive vertebrate bioactive peptide substances in hemocytes of the freshwater snail Viviparus ater (Gastropoda, Prosobranchia). 136 24

Daily hypoxia (6 h, 6000 m) changed the functional state of endocrine pancrease of male and female Wistar rats. The actions of hypoxia on functional state of supraoptic (SO) and paraventricular (PV) nuclei of hypothalamus and islet cells of endocrine pancreas were examined using immunocytochemical, histochemical, morphometric and radioimmunoassay methods. Increase of insulin biosynthesis in beta cells and glucagon secretion of alpha cells, and decrease of the somatostatin contents in delta cells of pancrease islets have been investigated. The functional activity of vasopressinergic magnocellular subnucleus of PV increased, but that of SO decreased with reduction of vasopressin blood concentration at the same time. The functional state of oxytocin synthesis subdivisions of PV and SO were sex dependent, but the oxytocin contents in median eminence increased.
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PMID:[Interactions of the macrocellular neurosecretory system of the hypothalamus and the endocrine pancreas of rats in adaptation to hypoxia]. 136 11

Oxytocin has been shown to influence insulin, glucagon and blood glucose levels in various experimental situations. The present study was performed in order to obtain support for a possible interaction of glucose and oxytocin under physiological conditions. We therefore studied whether or not short-term food deprivation (24 hours) affects basal oxytocin levels in male, female and lactating rats, since this is a situation when glucose is mobilized to prevent hypoglycaemia. Secondly, we studied whether oxytocin levels rise in a situation when blood glucose levels fall, i.e. following i.p. injection of insulin (20 U kg-1). In order to explore the role of oxytocin more directly, we investigated whether i.p. injection of the oxytocin antagonist 1-deamino-2-D-Tyr-(OEt)-4-Thr-8-Orn-oxytocin affects blood glucose levels. Plasma levels of oxytocin, insulin and glucagon were measured with radioimmunoassay in samples obtained after decapitation. We found that oxytocin levels were significantly increased following short-term food deprivation in lactating rats. We also found that insulin-induced hypoglycaemia could elevate plasma levels of oxytocin in female and male rats. In addition, administration of an oxytocin antagonist cause a small, but significant decrease in blood glucose levels after 30 min. These data imply that oxytocin may be one of several factors that take part in the control of blood glucose regulation.
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PMID:Plasma levels of oxytocin after food deprivation and hypoglycaemia, and effects of 1-deamino-2-D-Tyr-(OEt)-4-Thr-8-Orn-oxytocin on blood glucose in rats. 158 19

Oxytocin (OT) produced a dose-dependent increase in somatostatin, glucagon and insulin release by isolated mouse islets. A small effect on somatostatin release was observed with 0.1 nM-OT, but 1-10 nM-OT was required to affect A- and B- cells significantly. The effects of OT on somatostatin and glucagon release were similar in the presence of 3 mM- and 10 mM-glucose. No change in insulin release was produced by OT in 3 mM-glucose, but a stimulation was still observed in the presence of a maximally effective concentration of glucose (30 mM). The increase in insulin release produced by OT (in 15 mM-glucose) was accompanied by small accelerations of 86Rb and 45Ca efflux from islet cells. Omission of extracellular Ca2+ accentuated the effect of OT on 86Rb efflux, attenuated that on 45Ca efflux, and abolished that on release. OT never inhibited 86Rb efflux. It did not affect the resting potential of B-cells, but slightly increased the Ca2(+)-dependent electrical activity induced by 15 mM-glucose. OT did not affect cyclic AMP levels, but increased inositol phosphate levels in islet cells. It is suggested that the amplification of glucose-induced insulin release that OT produces is due to a stimulation of phosphoinositide metabolism, and presumably an activation of protein kinase C, rather than to a change in cyclic AMP levels or a direct action on the membrane potential. Since OT is present in the pancreas, it is possible that it exerts a neuropeptidergic control of the islet function.
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PMID:Mechanisms of the stimulation of insulin release by oxytocin in normal mouse islets. 167 63

The effect of total weaning (all piglets were weaned at 35 days of lactation) and fractionated weaning (the heavier half of the litter was weaned on day 33 of lactation and the remainder 2 days later) on plasma levels of prolactin, oxytocin, insulin, glucagon, glucose, gastrin and somatostatin in primiparous sows was studied. Twelve crossbred sows were grouped into six pairs according to farrowing data and litter size. The litter of one sow in each pair was weaned in two stages (treatment), and the other was conventionally weaned (control). Blood samples were collected via a permanent jugular vein catheter every 3 hours from 9 a.m. to 9 p.m. from day 31 of lactation until the third day of final weaning. In response to total weaning (studied in the six control sows), plasma prolactin, glucagon and gastrin decreased significantly, whereas plasma insulin and somatostatin significantly increased. Basal concentrations of plasma oxytocin and glucose remained unchanged after weaning. Fractionated weaning did not result in any significant differences in the hormonal and glucose levels as compared with the total weaning. The possible role of prolactin in modulating insulin, glucagon and glucose concentrations as well as the possibility that oxytocin affects gastrin and somatostatin levels following weaning are discussed.
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PMID:Effects of weaning on plasma levels of prolactin, oxytocin, insulin, glucagon, glucose, gastrin and somatostatin in sows. 167 12


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