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)

Rabbits were anesthetized with urethane and were given intracisternal injections of the following substances: adrenocorticotropin, beta-melanocyte stimulating hormone, choroid plexus peptide IIF, epinephrine, serotonin, histamine, oxytocin, lysine and a arginine vasopressins, acetylcholine and melatonin. The effects on the concentration of 3', 5' cyclic guanosine monophosphate (cGMP) in cerebrospinal fluid were then measured. Only melatonin and acetylcholine caused a significant (p less than 0.05) effect on cGMP concentration. Both agents increased the nucleotide's concentration within 30 min. Melatonin was about 1,000 times more potent than acetylcholine; the mininal effective doses were 1 mug and 1,000 mug, respectively.
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PMID:Injection of melatonin into cisterna magna increases concentration of 3', 5' cyclic guanosine monophosphate in cerebrospinal fluid. 18 65

The pineal nonapeptide hormone arginine vasotocin (AVT) is synthesized by the ependymal cells of the pineal recess and subcommissural organ and stored in so far undefined cells of the pineal gland proper. AVT is first released into the cerebrospinal fluid (CSF) and reaches the blood only secondarily after its absorption from CSF. It displays a diurnal rhythm in the pineal and CSF, suggesting its release into the CSF during the night in the dark. Melatonin represents its releasing hormone. AVT exerts both its endocrine and non-endocrine effects by a unique mechanism involving the activation of serotonin neurotransmission in the brain with resultant inhibition of release of hypothalamic releasing and inhibiting hormones and induction of sleep. It produces both its endocrine effects and sleep at concentrations equivalent to only several hundreds of molecules, being thus by far the most active hormone so far known. Midbrain raphe nuclei or some structures intimately correlated with these cell bodies, most contain the extremely sensitive and specific AVT receptors in the mammalian brain. In contrast with its natural analogues arginine vasopressin and oxytocin which are mainly blood hormones, AVT is a CSF hormone whose major if not the sole site of action is the brain itself.
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PMID:Arginine vasotocin as a pineal hormone. 22 41

The effect of melatonin as well as pinealectomy on the basal and K(+)-evoked release of vasopressin and oxytocin from the neurointermediate lobes in vitro was determined. Pineal removal resulted in a diminution of vasopressin and oxytocin release from the neurointermediate lobes in vitro. Melatonin (10(-3) or 10(-6) M/l) increased vasopressin and oxytocin release from neurointermediate lobes of sham-operated rats. Nevertheless, when pinealectomized rats served as donors of the neurointermediate lobes, melatonin (10(-3) or 10(-6) M/l) increased vasopressin release under basal conditions. For the same tissue, melatonin did not affect the oxytocin release either under basal conditions or during depolarization due to excess potassium. When 10(-7) M/l melatonin was used, no changes in either vasopressin or oxytocin release were observed in vitro.
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PMID:Melatonin, pinealectomy, and release of neurohypophysial hormones: in vitro studies. 156 28

Melatonin injected in a single intraperitoneal dose of 100 micrograms/100 g b.w. to euhydrated rats resulted in a decrease of neurohypophysial oxytocin content but the hypothalamic oxytocin storage as well as the hypothalamo-neurohypophysial storage of vasopressin were not changed. Following 8 d of once-daily melatonin treatment the hypothalamic and neurohypophysial oxytocin and vasopressin content was decreased. It might be therefore suggested that melatonin increases the release of neurohypophysial hormones and/or decreases their synthesis. Melatonin did not significantly modify the neurohypophysial vasopressin depletion rate in animals deprived of water up to 8 days. No consistent effects of melatonin on the decrease of hypothalamo-neurohypophysial content of oxytocin were noted under conditions of dehydration and simultaneous administration of melatonin up to 8 d.
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PMID:The influence of melatonin on the content of vasopressin and oxytocin in the hypothalamus and neurohypophysis in euhydrated and dehydrated male rats. 377 20

The effects of melatonin on the motility (isometric tension developed and contractile frequency) of uterine horns isolated from ovariectomized rats as well as on the mechanical responsiveness to added oxytocin or prostaglandin F2 alpha (PGF2 alpha) were explored. The pineal indole (10(-6) M or higher) depressed significantly the spontaneous motility of the uterus and reduced the responses evoked by oxytocin but not those evoked by PGF2 alpha. Melatonin was also tested on the prostaglandin (PG) release into the suspending media from either uterine horns from spayed rats or bovine medial basal hypothalamic (MBH) explants. Melatonin (10(-3) M) diminished the output from the uterus or the MBH of both PGE and PGF-"like material". Similarities between the effects of melatonin and indomethacin as well as the possible physiological relevance of the present findings are discussed.
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PMID:Melatonin blocks in vitro generation of prostaglandin by the uterus and hypothalamus. 610 21

The release of progesterone, estradiol-17 beta, oxytocin, arginine-vasopressin, cAMP, and cGMP by cultured granulosa cells isolated from porcine ovaries without and in the presence of melatonin (0.001, 0.01, 0.1, 1, 10, and 100 ng/ml medium) was analyzed. It was found that melatonin is able to inhibit progesterone and stimulate estradiol secretion. Melatonin treatments significantly inhibited oxytocin release. Some inhibition of vasopressin and cAMP and significant stimulation of cGMP also resulted from melatonin treatment. The present observations suggest a direct effect of melatonin on the steroid, nonapeptide hormone, and cyclic nucleotide release from porcine ovarian cells.
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PMID:Direct influence of melatonin on steroid, nonapeptide hormones, and cyclic nucleotide secretion by granulosa cells isolated from porcine ovaries. 789 82

Melatonin was shown to produce a tocolytic effect in experiments on the isolated uterine horn in different experimental animals and on the whole body. The ability of melatonin to inhibit uterine contractility was confirmed by the studies of the effects of melatonin on oxytocin-induced myometrial contractions. It may be suggested that the antagonism between melatonin and oxytocin is uncompetitive.
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PMID:[The tocolytic activity of melatonin]. 811 Dec 89

The effect of haemorrhage (1 ml per 100 g b. w.) on the vasopressin and oxytocin storage in the hypothalamus and neurohypophysis of melatonin-treated male rats was determined. Melatonin treatment (100 micrograms/100 g b. w., once daily over 8 days) resulted in a known decrease of vasopressin as well as oxytocin content both in the hypothalamus and neurohypophysis. Haemorrhage decreased the neurohypophysial vasopressin and oxytocin storage in animals injected with vehicle solution or otherwise not treated. In melatonin-treated rats, however, bleeding did not affect the actual (i.e., decreased by melatonin) vasopressin and oxytocin content in the hypothalamo-neurohypophysial system. The results demonstrate that melatonin may be involved in mechanisms determining the rate of the response of vasopressinergic and oxytocinergic neurones to bleeding.
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PMID:Hypothalamic and neurohypophysial vasopressin and oxytocin content as influenced by haemorrhage in melatonin-treated male rats. 836 9

The effect of haemorrhage and melatonin on the vasopressin and oxytocin storage in the neurohypophysis of pinealectomized male rats was determined. Sham operated or pinealectomized rats as well as rats pinealectomized and injected with melatonin (100 micrograms/100 g b. w., once daily over 8 days) or with melatonin vehicle (2.2% ethanol in 0.9% NaCl) were subsequently subjected to haemorrhage. Pinealectomy was followed by known decrease of both vasopressin and oxytocin content in the neurohypophysis as compared to sham operated rats. Similarly, haemorrhage decreased the neurohypophysial vasopressin and oxytocin storage in both sham operated and pinealectomized animals. Melatonin, injected to pinealectomized animals, did not modify the diminution of neurohypophysial vasopressin and oxytocin content caused by bleeding. The results demonstrate that in pinealectomized rats melatonin does not affect the rate of the response of vasopressinergic and oxytocinergic neurones to bleeding.
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PMID:The effect of haemorrhage and melatonin on neurohypophysial vasopressin and oxytocin content in pinealectomized male rats. 836 10

The secretion of neurohypophyseal hormone and ACTH in the rat has been shown to exhibit circadian rhythms, with high values during the day and low values throughout the night. The neurohypophyseal hormone daily rhythm is altered by exposure to constant light and by pinealectomy. It was, thus, proposed that the observed fall in vasopressin (AVP), oxytocin, and ACTH over the hours of darkness could be related to the release of melatonin seen at this time. Therefore, a study was performed to determine the effect of melatonin on AVP, oxytocin, and CRH-41 release from the isolated rat hypothalamus in vitro. Employing a previously validated technique, rat hypothalami were incubated in either medium alone or medium containing melatonin or one of two melatonin analogs. Hormone release was measured by RIA, and the ratios were calculated and compared by Student's t test, with Dunnett's correction for multiple comparisons. Melatonin showed a dose-dependent inhibition of both basal and stimulated AVP and oxytocin release in the concentration range 4.3 x 10(-10) to 2.5 x 10(-3) M, while having no significant effect on the release of CRH-41. The two melatonin analogs, 2-iodomelatonin and 5-methoxy-N-isobutanoyltryptamine, were also found to inhibit both basal AVP and oxytocin release, indicating that this effect probably depends upon the presence of melatonin receptors in the hypothalamus. This inhibitory modulation of AVP, in the absence of any effect on CRH-41, suggests that melatonin may affect water balance by means of directly inhibiting hypothalamic AVP release. Furthermore, circadian rhythmicity in pituitary-adrenal activity may depend on melatonin modulation of AVP, rather than changes in CRH-41.
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PMID:Melatonin and its analogs inhibit the basal and stimulated release of hypothalamic vasopressin and oxytocin in vitro. 844 Jan 90


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