Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Estradiol (0.2 mug), injected subcutaneously for 10 days to adult male rats, increased plasma growth hormone (GH) levels as compared with oil-treated controls. In estradiol-pretreated (10 days), urethane-anesthetized rats, the first as well as the second of two successive intracarotid injections, at 1-hour intervals, of one rat stalk median eminence equivalent evoked a significant rise in plasma radioimmunoassayable GH. Under the same conditions, cerebral cortex extracts (1 equivalent) induced a slight elevation whereas vasopressin (30 mU) or serotonin (200 ng) were ineffective. These results indicate that estrogen-primed, urethane-anesthetized rats can be used to demonstrate GH-releasing activity in rat SME extracts.
 ...
PMID:Effect of rat stalk median eminence extracts on rat GH secretion in vivo. 79 47

The incorporation of 3H-leucine into neurohypophyseal proteins was measured in vitro, 24 h after the administration of a single dose of estradiol (0.3 mug) to castrated female rats. Estradiol treatment caused a significant increase of 3H-leucine incorporation into proteins of the posterior lobe. The effects of estradiol depended largely upon time injection. Rats injected at 06.00 h, i.e., at the end of the dark period exhibited a 74% increase in protein synthesis, whereas rat injected at 14.00 h, i.e., at the middle of the light period only showed a 30% of increase.
 ...
PMID:Time-dependence of estradiol effects on protein synthesis in the rat neurohypophysis. 115 82

Increased knowledge on the mechanisms whereby corticotropin releasing hormone (CRH) and opioid peptides mediate the effects of stress has helped us to understand the relationship between stress and disturbed reproductive function. Increases of CRH and beta-endorphin in the hypothalamus in stressful situations inhibits the secretion of gonadotropins, oxytocin and vasopressin. This may lead to amenorrhea, which often is a consequence of intensive training or psychological stress, or it may disrupt parturition and lactation. There is a relationship between ovarian function and opioid peptides in the hypothalamus. Opioid peptides increase during puberty and fall at the menopause. Oestradiol and progesterone increase beta-endorphin concentrations in the luteal phase of the menstrual cycle, and this is followed by a rapid fall at menstruation. These changes may mediate symptoms typical of the premenstrual syndrome. Rather intensive exercise is required to increase plasma concentrations of beta-endorphin and corticotropin. During labour the amounts of beta-endorphin and corticotropin reach the values found in athletes during maximal exercise. The placenta produces increasing amounts of CRH towards the end of pregnancy which may help the mother and fetus to withstand the increased demands of labour. The placenta may thus be involved in the adaptation of the stress mechanism during pregnancy. CRH has also a paracrine function in different biological processes of the placenta and fetal membranes. It is possible to counteract the deleterious effects of stress on reproductive function by the administration of opiate antagonists. Induction of ovulation with naltrexone has been shown in patients with hypothalamic amenorrhea but the effect on fertility is not known.
 ...
PMID:Corticotropin-releasing hormone and opioid peptides in reproduction and stress. 175 18

Growth hormone (GH), prolactin (Prl) and cortisol secretion was studied in 5 ovariohysterectomized dogs before and after oestradiol implantation and medroxyprogesterone acetate (MPA) administration. MPA was given at regular intervals during a period of 10 months in a total of 12 injections. Short-term effects of oestradiol were restricted to significantly enhanced Prl responses to thyrotropin-releasing hormone (TRH). MPA treatment after oestradiol implantation resulted in significantly elevated basal GH levels in all dogs, with a continuing increase in one dog. Only in the latter dog was a significant decrease in basal Prl levels seen. MPA administration did not significantly change Prl responses to TRH. The GH responses to clonidine were significantly reduced at 9 and 16 weeks of oestradiol and MPA treatment. In the one dog which exhibited the greatest rise in basal GH levels, GH responses were completely abolished at 9, 16 and 43 weeks of oestradiol and MPA treatment. TRH never evoked significant GH responses. Both basal and lysine-vasopressin (LVP)-stimulated cortisol levels were significantly suppressed during combined oestradiol-MPA treatment. These findings denote that in the dog. Oestradiol rapidly induces an enhanced Prl response to TRH. The oestradiol-MPA induced GH overproduction is associated with a reduced responsiveness of GH to clonidine and is not accompanied by GH responsiveness to TRH. Oestradiol-MPA treatment suppresses both basal and LVP-stimulated cortisol secretion.
 ...
PMID:Medroxy-progesterone acetate administration to ovariohysterectomized, oestradiol-primed beagle bitches. Effect on secretion of growth hormone, prolactin and cortisol. 295 Jul 11

Previous studies have provided evidence for a discrete localization of two types of vasopressin (AVP)-labeled binding sites in the rat brain, i.e., regions labeled preferentially with AVP (putative AVP receptors) and regions labeled with AVP as well as oxytocin (OT). The latter binding sites are considered here as putative OT receptors. In the present study the effect of estradiol on the number of these putative receptor sites for OT and AVP was investigated in rat brain after daily subcutaneous administration of the steroid (10 micrograms/100 g body weight) to ovariectomized rats. Specific binding of [3H]-OT and [3H]-AVP was determined after in vitro incubation of frozen brain sections, autoradiography and quantitation of the images with computer-assisted densitometry. Estradiol increased the number of OT receptors at least 4-fold in the ventromedial nucleus of the hypothalamus, regions of the olfactory tubercle, the nucleus accumbens and occasionally in the organum vasculosum laminae terminalis. A smaller increase (two-fold) was noted in the central amygdala, while a tendency to a decrease in OT receptor number was noted in the olfactory nucleus and the ventral subiculum. Estradiol treatment permitted an estimation of binding constants of [3H]-OT-binding to a membrane fraction of microdissected ventromedial hypothalamic region (Kd: 1.3 nM, Bmax: 19.9 fmol/mg protein). The number of putative AVP receptors in the lateral septum and in the nucleus tractus solitarii was not affected by estradiol. In conclusion, the OT receptor system is subject to modulation by estradiol in some discrete brain regions, but not in others.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Estradiol modulates density of putative 'oxytocin receptors' in discrete rat brain regions. 302 14

We have studied the effects of 17 beta-estradiol on the left ventricular pressure and on the coronary perfusion pressure in isolated rabbit heart, in order to evaluate the action of this hormone on the myocardial contractility and on the coronary resistances. 17 beta-Estradiol has induced a negative inotropic effect starting from a concentration of 10(-6) M and a vasodilation starting from 10(-7) M when administered on a vasopressin-induced coronary spasm. These effects are not related to sex or to alpha-, beta-adrenergic, histaminergic, anaesthetic-like mechanisms, but seem to interfere with calcium transport.
 ...
PMID:Effects of 17 beta-estradiol on the isolated rabbit heart. 309 54

Activity of 40 single antidromically identified supraoptic neurons was recorded and evaluated in response to a combination of tactile, vulvar massage, vaginal distension, and slow intrajugular 1.2 M sodium chloride infusion in unanesthetized, randomly hydrated ewes. Estradiol-implanted Southdown ewes were prepared according to techniques described by Jennings et al. Only 4 spontaneous firing patterns were observed in the supraoptic nuclei. Analysis of evoked activity indicated that each stimulus evoked alterations in mean firing rates or increased numbers of short interspike intervals in some cells. The resultant activity of units to sequential vulvar massage and 1.2 M sodium chloride infusion suggests a possibility of separate mechanisms of release of oxytocin and vasopressin.
 ...
PMID:Effects of intrajugular hypertonic saline, vaginal distension and vulvar massage on activity of supraoptic neuroendocrine cells. 397 Nov 61

The regulation of pituitary enkephalin system by gonadal steroid hormones and psychotropic drugs was studied. A distinct sex-related difference of (Met5)- and (Leu5)-enkephalin-like immunoreactivity (ME-LI and LE-LI, respectively) was found in the anterior lobe but not in the neurointermediate lobe. Levels of ME-LI and LE-LI in the anterior pituitary of male rats were 4.8- and 6.2-fold as much as those of female rats, respectively. Estradiol administration caused a marked decrease of ME-LI and LE-LI only in the anterior lobe of male rats whereas dihydrotestosterone treatment significantly increased the level of ME-LI in the anterior lobe of female rats. Castration of male rats decreased both ME-LI and LE-LI only in the anterior lobe, and the diminished levels of both peptides were partially restored by the administration of dihydrotestosterone. On the other hand, ovariectomy caused a significant increase in both ME-LI and LE-LI in the anterior lobe of female rats, and this increase was completely prevented by the administration of estradiol. These results indicate that the enkephalin system in rat anterior pituitary is regulated by circulating gonadal steroid hormones. The anterior pituitary levels of ME-LI and LE-LI were significantly reduced by the repeated administration of haloperidol or lithium chloride, whereas hypertonic NaCl loading elicited no effect. On the other hand, ME-LI and LE-LI levels in the neurointermediate lobe were significantly decreased by repeated administration of hypertonic NaCl solution or lithium chloride; both treatments caused a marked reduction of antidiuretic hormone level in the same lobe. These results suggest that the regulation of the enkephalin system in the anterior lobe may be mediated, at least in part, by the dopamine system, whereas the enkephalin system in the neurointermediate lobe may be regulated mainly through a mechanism similar to that regulating antidiuretic hormone release.
 ...
PMID:The enkephalin system in the rat anterior pituitary: regulation by gonadal steroid hormones and psychotropic drugs. 631 13

The pituitary gland of the red grouper, Epinephelus akaara, was studied by histochemical techniques, and the prolactin cells, corticotrops, somatotrops, gonadotrops, thyrotrops, pars intermedia cells and neurohypophyseal cells, were identified. Oestradiol-17 beta treatment caused PAS-positive cells in the proximal pars distalis, presumably a mixture of gonadotrops and thyrotrops, to undergo hypertrophy, vacuolation and degranulation of cytoplasmic glycoprotein granules. Disappearance of cytoplasmic granules was also evident in the PAS-positive pars intermedia cells. Oestrogen-treated fish also showed an increase in the hepatosomatic index, and hepatocytes enlarged in size, their nuclear diameter increased and large vacuoles were formed in the cytoplasm. These changes in the liver were paralleled by a secretion of vitellogenin into the serum and an increased production of mucus by the thickened skin epithelium. Testosterone injections did not affect such changes, neither in the pituitary nor liver cells, but a proliferation of skin epithelial cells was noted. Neither oestradiol-17 beta nor testosterone stimulated ovarian incorporation of vitellogenin, but treatment with high doses (5 mg/kg) of oestradiol-17 beta or testosterone brought about a slight increase in the gonadosomatic index and atresia of some of the primary oocytes. The oogonial population size decreased in response to treatment with high doses of oestradiol-17 beta.
 ...
PMID:Effects of oestradiol-17 beta and testosterone on the histology of pituitary, liver, ovary and skin of previtellogenic Epinephelus akaara (Teleostei, Serranidae). 668 93

Bolus intravenous injections of 100 micrograms/kg 17 beta-estradiol significantly decreased the pressor responses to norepinephrine (NE; 0.3 microgram/kg) at the fourth, fifth, and sixth hour in anesthetized male Sprague-Dawley rats. At doses of 10(-6) to 3 x 10(-5) M, 17 beta-estradiol relaxed the sustained phase of contraction in male Sprague-Dawley rat tail artery helical strips precontracted in vitro by [Arg8]vasopressin (AVP), KCl, or NE. The effect was dose dependent. At doses of 3 x 10(-6) to 3 x 10(-5) M, it also decreased the initial phase of tension generation and extracellular Ca(2+)-dependent vasoconstriction induced by NE, AVP, or KCl in a dose-dependent manner in male Sprague-Dawley rat tail artery helical strips. 17 beta-Estradiol (2 x 10(-8) to 2 x 10(-6) M) decreased the voltage-dependent inward Ca2+ current and the intracellular free Ca2+ concentration ([Ca2+]i) increment induced by 15 mM KCl in a dose-dependent manner (3.6 x 10(-8) to 3.6 x 10(-6) M) in vascular smooth muscle cells (VSMC) isolated from male Sprague-Dawley rat tail arteries. We suggest that, at pharmacological doses, estrogen has a direct vasodilating effect on the rat tail artery that is mediated by its inhibitory effect on Ca2+ influx through voltage-dependent Ca2+ channels. The inhibitory effect of estrogen on the pressor responses to NE or AVP may be correlated with its modulation of VSMC [Ca2+]i through its actions on membrane Ca2+ channels.
 ...
PMID:Vascular effects of 17 beta-estradiol in male Sprague-Dawley rats. 816 Aug 45


1 2 3 Next >>