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

The effects of prolactin and other hormones applied electrophoretically to 400 neurons in the brain were studied in rats under urethane anesthesia. 51 prolactinactivated neurons were distributed mainly in the nucleus dorsomedialis, the upper part of the nucleus ventromedialis, and the nucleus habenulae. 26 prolactin-inhibited neurons were diffusely distributed from the nucleus arcuatus to the zona incerta. Prolactin failed to affect the neurons of the cerebral cortex. Almost all units recorded in the preoptic and lateral hypothalamic areas were not affected. About half of both prolactin-activated and -inhibited neurons were suppressed by estrogen and betamethasone but were not affected by either oxytocin or thyrotropin releasing hormone. This study affords direct evidence for the presence of prolactin-sensitive neurons in the hypothalamus.
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PMID:Effects of iontophoretically-applied prolactin on unit activity of the rat brain. 81 Jul 35

Plasma levels of prolactin and TSH were determined by radioimmunoassay in urethaneanaesthetized lactating rats during suckling. Oxytocin release was monitored by recording intramammary pressure. Application of ten pups, 3 h after administration of urethane (1-1 g/kg, i.p.), evoked a parallel rise in prolactin and TSH concentrations which reached a maximum during the 3rd hour of suckling and then declined. Peak hormone concentrations represented a 25-fold increase in prolactin and a ten-fold increase in TSH. Suckling also elicited a pulsatile (every 5-10 min) release of 0-5--1-0 mu. oxytocin. The gradual rise in prolactin and TSH occurred between the 1st and 20th oxytocin pulses. Intravenous injection of thyrotrophin-releasing hormone (TRH) into unsuckled, anaesthetized lactating rats resulted in a 7- to 30-fold increase in TSH concentration, whereas prolactin levels showed no substantial change. These results indicate that suckling releases TSH as well as prolactin in the urethaneanaesthetized rat. However, the absence of prolactin release after injections of TRH makes it unlikely that both endocrine responses are regulated solely by the actions of this one releasing hormone.
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PMID:Plasma concentrations of prolactin and thyrotrophin during suckling in urethane-anaesthetized rats. 82 93

Glutathione-insulin trandhydrogenase (GIT) activity has been shown to be stimulated in culture of explants of pregnant mouse mammary gland by a mixture of insulin, cortisol, and prolactin. Since this hormone mixture stimulates lactogenesis in vitro it is possible that the increase in GIT activity is functionally related to one of the processes of milk secretion or ejection. Oxytocin is degraded by GIT and the interaction of this hormone with its mammary gland receptors may be influenced by the change in enzyme activity. The increase in GIT activity caused by insulin, cortisol, and prolactin in vitro can be prevented by the addition of progesterone or oxytocin to the culture medium.
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PMID:Glutathione-insulin transhydrogenase activity in pregnant mouse mammary gland: hormonal influences studied in tissue culture. 85 85

Sensitivity to pain and touch was measured in the nipple, areola, and cutaneous breast tissue of prepubertal boys and girls, postpubertal men and nuliparous women before and after delivery. Before puberty there were no differences between the sexes, but after puberty the tactile sensitivity of all areas of the women's breast was significantly greater than the men's. Tactil sensitivity of all areas also varied during the menstrual cycle, with maximal sensitivity at midcycle and at menstruation; the mid-cycle peak was absent when the women were taking oral contraceptives. But the most dramatic changes occured within 24 hours of parturition, when there was a great increase in breast sensitivity. This may be the key event for activating the suckling-induced discharge of oxytocin and prolactin and inhibiting ovulation during lactation.
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PMID:Changes in breast sensitivity at puberty, during the menstrual cycle, and at parturition. 86 31

In eight patients undergoing chronic hemodialysis, ultrafiltration was performed for 1 h in each patient. The concentration of urea nitrogen, creatinine, ADH, cortisol, GH, prolactin and TSH was measured in plasma and the filtering solution, and the permeability of each substance was determined. The plasma concentration of ADH coincided with that of the filtering solution, and no significant difference was noted between the permeability of creating and ADH. In contrast, cortisol, GH, prolactin and TSH were not detected in the filtering solution. Chromatographic study showed that ADH in the filtering solution coincided with synthetic ADH. From a comparison of the permeability with the molecular weight, it was suggested that ADH in the blood exists in free form without binding with plasma proteins or neurophysin.
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PMID:Permeability of antidiuretic hormone and other hormones through the dialysis membrane in patients undergoing chronic hemodialysis. 91 84

Chronically-cannulated female rats that had been adapted to frequent handling were used for a kinetic study where oxytocin was injected into an indwelling atrial cannula and blood sampled every 5-10 min for 2 hr after the injection. The plasma was assayed for prolactin and LH by radioimmunoassay, in order to ascertain whether in cycling rats oxytocin exerts any effect on the circulating level of either hormone. The advantage of this experimental model is that each animal served as a control for itself, and that only minor stress was recorded during the experiments. The results suggest that oxytocin does not alter circulating LH levels, and complement previous reports on the lack of effect of oxytocin on serum prolactin in the cycling rat.
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PMID:Serum prolactin and LH in chronically-cannulated cycling rats after intra-atrial administration of oxytocin. 98 91

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

An attempt has been made to evaluate the importance of prolactin and 'progesterone withdrawal' for lactogenesis. The experimental model system used was the ovariectomized, non-pregnant ewe induced to lactate artifically by treatment with trigger hormone (either oestrogen, glucocorticoid or oxytocin) alone or in combination with progesterone. It appears from the results that prolactin is important in the lactogenic responses elicited by oestrogen and oxytocin but not as important in the response elicited by glucocorticoid. Moreover, the results suggest that, in the ewe, an appropriate positive hormonal stimulus will overcome the inhibitory influence of progesterone on lactogenesis.
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PMID:Artificial induction of lactation in ewes: the involvement of progesterone and prolactin in lactogenesis. 103 98

Mammary glands of rats on day 14 of lactation were emptied of milk by the pups after 8 h of nonsuckling with the aid of oxytocin injections to the mother. The glands subsequently refilled about 50% within 6 h and were completely refilled with mild within 16 h. Suckling for 5 min midway during the 8 h period of nonsuckling caused complete refilling of the glands within 6 h. Refilling within 6 h also occurred if, instead of suckling, rat prolactin was injected at 1 min intervals directly into the circulation of the conscious mother via an indwelling right atrial catheter. Five injections of 200 ng or three injections of 400 ng were without effect (in comparison with five injections of saline) upon mammary refilling whereas 10 injections of 200 ng or four injections of 400 ng simulated significant but submaximal refilling. Complete refilling resulted from five injections of 400 ng. Prolactin is secreted steadily over prolonged periods of suckling in the rat, but only that prolactin released during the first few minutes of suckling appears to be required for milk secretion.
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PMID:Milk secretory response of the conscious lactating rat following intravenous injections of rat prolactin. 120 34

The effect of L-DOPA on milk ejection and on prolactin release during 30 min of suckling was studied in lactating rats. Various doses of L-DOPA (1-25, 2-5, 5 and 10 mg/100 g body wt) were injected i.p. 30 min before the suckling period. Control rats were injected with 0-9% NaCl solution only. An inhibition of milk ejection proportional to the dose of drug administered was obtained. The dose of 10 mg completely blocked milk ejection but 1-25 mg had no effect. A normal milk-ejection response was obtained with a small dose of oxytocin injected immediately before nursing into mothers treated with 10 mg L-DOPA, indicating that the blocking effect was not due to a lack of mammary gland response. In control mothers, serum prolactin levels increased from 67-2 +/- 25-9 (S.E.M.) to 950-3 +/- 118-7 ng/ml after a 30 min suckling period. L-DOPA (5 and 10 mg) prevented the release of prolactin induced by suckling, but 1-25 and 2-5 mg L-DOPA had no effect. The results indicate that oxytocin and prolactin release induced by suckling in lactating rats is inhibited by an increase of catecholamines at the hypothalamic-hypophysial axis.
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PMID:Effect of L-dopa on milk ejection and prolactin release in lactating rats. 120 26


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