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)

Plasma concentrations of oestrogen-stimulated neurophysin (ESN), prolactin, and growth hormone were measured before and after the first treatment in a course of electroconvulsive therapy (ECT) given to 25 psychiatric patients and during induction of anaesthesia in 9 women undergoing elective cholecystectomy. Prolactin levels rose and growth hormone levels fell during both cholecystectomy and ECT, but ESN levels rose only after ECT. The peak ESN response to ECT was significantly greater (p less than 0.005) in the 16 depressed patients who recovered than in the 9 who did not. All patients in whom plasma ESN concentration increased by more than 100% satisfactorily recovered from their depressive illness. If a 63% increase in ESN concentration is used to classify all subjects, 12% are misclassified by outcome at 2 months. The extent of the ESN response, but not the prolactin or growth hormone responses, correlated with improvement in symptoms measured by Hamilton Rating Scale for Depression and the Montgomery and Asberg Depression Rating Scale.
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PMID:Oestrogen-stimulated neurophysin and outcome after electroconvulsive therapy. 287 18

Prolactin has been shown to increase the activity of ornithine decarboxylase in a variety of mammalian tissues and in the pigeon crop sac. This study demonstrates a similar effect of ovine prolactin on ornithine decarboxylase activity in liver slices taken from larval tiger salamanders (Ambystoma tigrinum). An evaluation of potential mediators of prolactin action in liver slices revealed that the effect of the hormone on enzyme activity was not blocked by ouabain, an inhibitor of the sodium pump reported to block other actions of prolactin. Oxytocin, which inhibits prolactin actions in A. tigrinum, blocked the increase in ornithine decarboxylase activity induced by prolactin. Since previous results had implicated inositol phospholipid turnover in oxytocin action, the effects of the calcium ionophore, A 23187, and of synthetic diacylglycerol were examined. Both agents blocked the increase in enzyme activity when they were combined with prolactin treatment. Verapamil, a calcium channel blocker, had a prolactin-like effect on the activity of ornithine decarboxylase, and the combination of prolactin and verapamil produced a stimulation of the enzyme that was no greater than that observed with either the drug or prolactin alone, suggesting that both agents might be acting via a common cellular pathway. The tentative hypothesis that prolactin acts via a mechanism which lowers intracellular calcium is suggested.
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PMID:Enhancement of ornithine decarboxylase activity in Ambystoma liver slices by ovine prolactin: an evaluation of possible mediators. 314 Dec 45

Prolactin along with corticosterone is a stress responsive hormone. Evidence suggests that oxytocin (OXT) modulates not only ACTH secretion but also prolactin release. The present study was therefore designed to examine the possible role of oxytocin in the corticosterone and prolactin response to predictable and unpredictable novelty stress. Repeated stress and oxytocin treatment produced a substantial increase in corticosterone. A greater increase was obtained for the larger OXT dose (11.6 IU/kg) than for the smaller dose (5.8 IU/kg). In addition, for the smaller oxytocin dose only, unpredictable exposure to the novelty apparatus produced a more substantial increase in corticosterone than predictable exposure to the same stressor. In contrast, oxytocin produced a significant suppression of the prolactin response in all OXT treated animals. No significant interaction between stress and oxytocin was obtained. It was concluded that an important role exists for oxytocin in the modulation of both corticosterone and prolactin secretion.
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PMID:Influence of exogenously administered oxytocin on the corticosterone and prolactin response to psychological stress. 341 97

Five amphibian species were studied for the effect of hypophysial hormones on their water balance. The species were three anurans, Rana ridibunda, Bufo viridis and Pelobates syriacus, and two urodeles Salamandra salamandra and Triturus vittatus. In the first four species different stages of development were studied, in the newt both the terrestrial and aquatic phases of the adult were examined. The hormones used were oxytocin (OXY), arginine vasotocin (AVT) and prolactin (PL). Oxytocin caused most water retention when compared with the other hormones, especially responding were juveniles of Rana and Bufo, but also the terrestrial phase of the adult newt Triturus. Arginine vasotocin affected mostly juvenile Pelobates. Prolactin caused water retention in juvenile Rana and in the terrestrial phase of Triturus. In general the hormones affected the juvenile stages more than either larvae or adults.
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PMID:Water balance of five amphibian species at different stages and phases, as affected by hypophysial hormones. 613 81

Prolactin production by human decidua was examined with the use of a short-term tissue explant system. Decidua obtained after normal spontaneous vaginal deliveries produced significantly more prolactin than did tissue obtained after elective repeat cesarean section deliveries in the absence of labor (P less than 0.005). Cytosolic prolactin levels did not differ between the two delivery modes. Oxytocin (4.3 X 10(-11) M to 4.3 X 10(-6) M) and eicosatetraenoic acid (10(-7) M to 10(-4) M) had no effect on prolactin production or storage by decidual tissue. Indomethacin at 10(-4) M reduced only levels of stored prolactin but had no effect on stored or produced prolactin at lower concentrations (10(-7) M to 10(-5) M). Arachidonic acid (10(-4) M) suppressed both production and storage of prolactin (P less than 0.05). Decidual tissue from the two delivery modes did not differ in response to the above agents. Although the exact mechanism(s) remains obscure, these results indicate decidual prolactin production is altered by some aspect of labor. The possible involvement of prostaglandin precursors in mediating this production cannot be excluded.
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PMID:Prolactin secretion by human chorion-decidua in vitro: influences of mode of delivery and agents that modify prostaglandin synthesis. 661 83

The effects of exogenous noradrenaline on the milk-ejection response were determined for nine Holstein cows. Noradrenaline was injected (0.95 nmol/kg) 15 s after the start of teat stimulation (preparation) or infused (0.13 nmol/kg per min, after bolus injection of 0.47 nmol/kg) starting 10 min before milking for 20 min. Cows were prepared (udder wash and dry) for 1 min before milking. Both injection and infusion resulted in approximately a 3.5-fold increase in peripheral noradrenaline at 1.75 min after the start of milking (baseline noradrenaline 0.83 and 0.89 nmol/l plasma; at 4 min, 2.00 and 3.00 nmol/l). Prolactin release was delayed and oxytocin release enhanced, while milk yield was decreased by 8.6% for both treatments. The maximum rate of milk flow was also depressed by treatment. In contrast, milking time increased for injection and decreased for infusion. In addition, a milk-yield-dependent change in the pattern of milk flow was seen in response to treatment. In medium-yield animals, two distinct milk-flow peaks were apparent and injection delayed the time to the second peak. We conclude that physiologically meaningful increases in peripheral noradrenaline can inhibit milk-ejection response by means of a peripheral mechanism not involving inhibition of release of oxytocin.
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PMID:Small increases in peripheral noradrenaline inhibit the milk-ejection response by means of a peripheral mechanism. 669 36

Prolactin secretion was stimulated in 5 cyclic gilts during the luteal phase (Day 10-13) with 5 mg haloperidol given i.v. Stimulation of prolactin secretion was also attempted by inducing milk let-down by suckling (4 sows), or by the injection of 1 mg oxytocin i.v. followed by hand milking (3 sows). Plasma prolactin concentrations increased significantly 1-2 h after haloperidol injection, and in 3 of 4 sows during suckling (P = 0.001); plasma relaxin concentrations did not change significantly at these times. No change was observed in plasma prolactin or relaxin concentrations at 15 min or 1-2 h after oxytocin injection and hand milking. Plasma relaxin concentrations ranged from below the sensitivity of the assay (100 pg/ml) to 450 pg/ml in lactating sows and from 100 to 2000 pg/ml in cyclic gilts. The results suggest that in cyclic gilts treated in the luteal phase with a dopaminergic receptor blocker, and in lactating sows during suckling, elevations in plasma prolactin concentrations were not accompanied, during the same period, by detectable changes in relaxin concentrations.
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PMID:Effect of haloperidol, suckling, oxytocin and hand milking on plasma relaxin and prolactin concentrations in cyclic and lactating pigs. 688 39

Prolactin-releasing (PRF) activity was found in Pitressin (a commercial extract from posterior pituitary for vasopressin). Injection of Pitressin into conscious free-moving rats implanted with a permanent atrial indwelling cannula, produced a transient increase in prolactin concentration in the circulation. In order to find out whether the PRF activity was due to vasopressin or to an unidentified component in the Pitressin, we tested synthetic lysine vasopressin and demonstrated that vasopressin (1 U/kg) elevated plasma prolactin concentration about threefold. In contrast, oxytocin (1 U/kg) did not alter the prolactin concentration. In order to find out whether the effect of vasopressin is a direct or indirect action, we tested the vasopressin effect on hypophysectomized rats which had previously been implanted with 2 adenohypophyses under the kidney capsule. Again this dose (2 U/kg) of vasopressin elevated circulating plasma prolactin. These experiments indicate that vasopressin can elevate circulating prolactin concentration in nonestrogen-primed normal male rats and that vasopressin also stimulates prolactin secretion from transplanted glands dissociated from direct hypothalamic control.
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PMID:Vasopressin has a direct effect on prolactin release in male rats. 705 60

Breastfeeding delays the resumption of normal ovarian cycles by disrupting the pattern of pulsatile release of GnRH from the hypothalamus and hence LH from the pituitary. The plasma concentrations of FSH during lactation are sufficient to induce follicle growth, but the inadequate pulsatile LH signal results in a reduced estradiol production by these follicles. When follicle growth and estradiol secretion does increase to normal, the suckling stimulus prevents the generation of a normal preovulatory LH surge and follicles either fail to rupture, or become atretic or cystic. Only when the suckling stimulus declines sufficiently to allow generation of a normal preovulatory LH surge to occur will ovulation take place with the formation of a corpus luteum of variable normality. Thus suckling delays the resumption of normal ovarian cyclicity by disrupting but not totally inhibiting, the normal pattern of release of GnRH by the hypothalamus. The mechanism of suckling-induced disruption of GnRH release remains unknown. It does not appear to involve prolactin, dopamine or opiates although a combination of these factors might be involved. Prolactin is the major hormone responsible for milk production and is present in sufficient quantities in almost all women to allow the establishment of normal lactation. Oxytocin is essential for milk let down and is susceptible to inhibition of release by stress. The successful initiation of lactation which would lead to the potential of utilizing breastfeeding as contraceptive may require more attention to be paid to the establishment of non-stress release of oxytocin.
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PMID:Physiological mechanisms underlying lactational amenorrhea. 815 98

Prolactin-producing cells (PRL cells) identified by immuno-electron microscopy were studied in male rats with chronic intraperitoneal injection of synthetic oxytocin (OT). The PRL cells are usually classified into three types: the immature type containing round secretory granules about 100 nm in diameter with poorly developed cell organelles; the intermediate type containing medium-sized (150-250 nm in diameter) secretory granules with moderately developed cell organelles; and mature type containing large pleomorphic secretory granules ranging from 300 to 700 nm in diameter with well-developed cell organelles. In male rats, the intermediate type comprises typical PRL cells that constitute about 50% of all immunoreactive PRL cells. Chronic intraperitoneal OT administration to rats caused morphologically hypertrophic and hyperfunctioning PRL cells which are identified as mature type PRL cells. The frequency of occurrence of the mature type PRL cells increased after treatment. The contents of pituitary and serum PRL as measured by radioimmunoassay essentially paralleled the morphological results. These data indicate that OT may play a physiological role in PRL secretion as a releasing factor, and that OT administration causes the interconversion of the three types of PRL cells, indicating the mature type to be at the most activated state of secretory function.
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PMID:Influence of exogenously administered oxytocin on prolactin-producing cells in adult male rats as revealed by immuno-electron microscopy. 828 52


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