UNIPROT:P01189 - FACTA Search

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Query: UNIPROT:P01189 (beta-endorphin)
21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of the ovarian steroids, oestradiol benzoate (EB), and progesterone (P) on the cells of pars intermedia (PI) from chronically ovariectomized rats (CHR-OVX) were analyzed by qualitative and quantitative electron microscopy (EM) at different intervals after steroid injection. The PI cells of CHR-OVX are rich in secretory granules but poor in organelles related to hormonal synthesis. Twenty-four h after EB administration the cells exhibited cytological features indicative of an increased synthetic activity. These included hypertrophy of rough endoplasmic reticulum, cisternae, a moderately developed Golgi complex, and newly formed granules. These features were also observed in PI cells 48 h after EB administration. Thirty-two and 56 h after the treatment, the PI cells showed signs of both increased synthetic and secretory activity. Thus, it was possible to observe a well-developed rough endoplasmic reticulum, and Golgi apparatus, numerous electron-lucent vesicles, and secretory granules in contact with the cell membrane. However, no exocytotic figures were observed. Progesterone administration resulted in considerable modifications of the ultrastructural features of PI cells also indicative of increased synthetic and secretory activity. The greatest modifications were observed in the mornings with changes that were 12 h out of phase with respect to those observed with EB. Quantitative estimations of the variation in the content of secretory granules of PI cells fully confirmed the qualitative observations described above. The serum alpha-MSH concentrations in ovariectomized rats was found to be increased 24 h after administration of a single dose of EB and thereafter serum MSH exhibited high levels in the afternoon, whereas the values in the morning were lower.
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PMID:Modifications of pars intermedia cells of ovariectomized rats by oestrogen and progesterone. 394 2

Sexually experienced male rats were used to test the attractiveness of preputial gland odours of female rats. The male rats showed a clear preference for the preputial gland odours of hypophysectomized females given oestradiol benzoate (OB) for 3 or 8 days to those of control rats. Progesterone treatment had no effect on the attractiveness of the preputial gland odours of OB-treated hypophysectomized female rats. Administration of alpha-MSH for either 3 or 8 days, on the other hand, increased the attractiveness to male rats of preputial gland odours of OB-treated hypophysectomized females and the presence of progesterone produced no further change. When administered alone alpha-MSH had no effect on the attractiveness of the preputial gland odours. Other pituitary hormones, such as ACTH and prolactin, had no effect on the attractiveness of preputial gland odours of OB-treated hypophysectomized rats when administered for 3 days. An increase in preputial gland size was only seen when OB, progesterone and alpha-MSH were administered together. It would appear that no relationship exists between the size of the preputial glands and their ability to attract male rats. It is concluded that, while alpha-MSH and progesterone may be important in controlling growth of the preputial glands, an interaction between alpha-MSH and oestrogen is more important for regulating the production of sex attractants by the preputial glands.
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PMID:Effect of alpha-melanocyte-stimulating hormone and ovarian steroids on preputial gland function in the female rat. 626 52

Human fetal adrenal (HFA) tissue was maintained in organ culture to evaluate the biosynthesis of prostaglandins and hormonal regulation of prostaglandin formation by this tissue. The HFA tissue secreted substantial amounts of prostaglandin E(2), prostaglandin F(2alpha), 13,14-dihydro-15-ketoprostaglandin F(2alpha), 6-ketoprostaglandin F(1alpha), and thromboxane B(2); secretion of prostaglandin D(2) could not be demonstrated. Prostaglandin biosynthesis in HFA tissue was inhibited in a time-dependent manner by corticotropin (ACTH; 0.4 muM); by the fourth day of culture, the extent of inhibition of biosynthesis of each prostaglandin was 60-90%. Progesterone (1 muM), cortisol (1 muM), and dexamethasone (1 muM) inhibited prostaglandin biosynthesis whereas estradiol (1 muM) did not. Of the compounds tested for inhibitory activity, dexamethasone was the most potent. An inhibitor of 11beta-hydroxylase activity (metyrapone; 0.1 mM) effectively eliminated the inhibition of prostaglandin biosynthesis caused by corticotropin and progesterone. Metyrapone treatment alone caused a 3-fold increase in prostaglandin biosynthesis by fetal adrenal tissues. Similar stimulatory effects resulted from treatment with inhibitors of (i) 3beta-hydroxysteroid dehydrogenase (cyanoketone; 15 muM), (ii) steroid 17alpha-hydroxylase (SU 10603; 19 muM), and (iii) cholesterol side-chain cleavage (aminoglutethimide; 1 mM). Inhibition of prostaglandin biosynthesis by dexamethasone in the presence or absence of metyrapone was concentration dependent and 50% inhibition could be demonstrated at 1 nM. A competitive inhibitor of the binding of glucocorticosteroids to cytoplasmic receptors (cortisol 21-mesylate; 1 muM) significantly reduced the inhibition of prostaglandin biosynthesis effected by dexamethasone (10 nM). These findings suggest that prostaglandin biosynthesis in the HFA gland is regulated by endogenously synthesized glucocorticosteroids, the actions of which are mediated by a glucocorticosteroid receptor. Such glucocorticosteroids induce the synthesis of a substance that inhibits prostaglandin biosynthesis.
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PMID:Prostaglandin biosynthesis in the human fetal adrenal gland: regulation by glucocorticosteroids. 629 39

The present study examined the association between hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-ovarian axes. HPA activity determined by plasma levels of adrenocorticotropin (ACTH) and corticosterone (B) was assessed in intact female rats as a function of oestrous cycle stage under resting conditions and after exposure to a 20 min restraint stress. To delineate the roles of oestradiol and progesterone in HPA axis modulation, plasma concentrations of ACTH and B were determined in ovariectomised (OVX) animals treated with oestradiol and/or progesterone under resting conditions and during exposure to the stress of a novel environment. The effects of these steroid treatments on the transcription and/or binding properties of the two corticosteroid receptors, the mineralocorticoid (MR) and glucocorticoid (GR) receptors, were also examined in hippocampal tissue, (i) Fluctuations in basal and stress-induced plasma ACTH and B concentrations were found during the oestrous cycle with highest levels at late pro-oestrus. (ii) In OVX steroid-replaced animals, basal and stress-induced activity was enhanced in oestradiol and oestradiol plus progesterone-treated animals compared with OVX controls. (iii) Cytosol binding assays revealed an oestradiol-induced decrease in hippocampal MR capacity. This decrease appears to be due to an effect of the steroid on MR transcription as in situ hybridisation analysis of MR mRNA showed an oestradiol-induced decrease in MR transcript in all hippocampal subfields. (iv) Treatment of oestradiol-primed animals with progesterone reversed the oestradiol-induced decrease in hippocampal MR capacity. Data from MR mRNA hybridisation in situ experiments indicate that this reversal may be due to an antagonism of the oestradiol effect on MR transcription. (v) Progesterone treatment with or without prior oestradiol-priming induced a significant decrease in the apparent binding affinity of hippocampal MR. We show that progesterone and its 11 beta-hydroxylated derivative have a high affinity for the hippocampal MR. (vi) Neither oestradiol nor progesterone affected GR binding parameters in the hippocampus. In conclusion, we find that sex steroids modulate HPA activity and suggest that the observed effects of these steroids on hippocampal MR may underlie their concerted mechanism of action in inducing an enhanced activity at the period of late pro-oestrus.
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PMID:The influence of ovarian steroids on hypothalamic-pituitary-adrenal regulation in the female rat. 770 84

Ovarian steroids exert feedback effects at the level of both the hypothalamus and anterior pituitary to regulate the secretion of gonadotrophins. Oestradiol decreases the activity of mRNA encoding the alpha and beta subunits of gonadotrophins. In the late follicular phase, oestradiol exerts a positive feedback control over pituitary luteinizing hormone (LH) release and a negative control over follicle stimulating hormone (FSH). Oestradiol also induces a pre-ovulatory increase of gonadotrophin releasing hormone (GnRH) secretion which is continuous rather than episodic. Such a GnRH rise may not be required to produce the LH surge. Progesterone exerts its major effect at the hypothalamic level and decreases GnRH pulse frequency by inducing the release of beta-endorphin. However, the hypothalamus is not the exclusive target of progesterone action, for its facilitatory action on gonadotrophin release may be at the level of the pituitary gland. This positive feedback effect was studied in women with hypothalamic gonadotrophin deficiency treated with pulsatile GnRH. In physiological doses, progesterone had a stimulatory effect on LH secretion at the pituitary level. Finally, regarding the effect of androgens upon gonadotrophin secretion, the administration of a non-steroidal pure anti-androgen (Flutamide) for 12 months in 10 normally cycling women did not change significantly the mean levels, frequency, or amplitude of LH pulses or the LH and FSH responsiveness to GnRH. Androgens (apart from their aromatization to oestrogens) do not directly play a physiological role in gonadotrophin regulation in normal women.
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PMID:The control of gonadotrophin secretion by ovarian steroids. 827 77

We have investigated the role of the gonadal steroids testosterone (T) and progesterone in modulating: (1) the onset and severity of adjuvant-induced arthritis (AA), (2) the response of the hypothalamo-pituitary-adrenal (HPA) axis, and (3) the levels of plasma prolactin and anterior pituitary prolactin messenger ribonucleic acid (mRNA) in the rat. Male rats were castrated (CSX) and received either no T, low T or high T delivered using silastic implants. In a second study experimental groups comprised CSX/AA, CSX/AA + progesterone or CSX/AA + progesterone + T. The time of onset was sooner and the severity of AA was greater in CSX rats. Inflammation was prevented by T replacement. Endogenous plasma T levels were decreased in AA rats. In control animals with AA there was an increase in pro-opiomelanocortin (POMC) mRNA in the anterior pituitary and of plasma corticosterone, and a decrease in corticotrophin-releasing factor (CRF) mRNA. These changes in the HPA axis of AA and CSX/AA rats were reversed by T replacement. These data suggest that T has an important protective effect on the progress and severity of AA. This was reflected by a reversal of the neuroendocrine changes of the HPA axis. Progesterone treatment alone had no effect on the severity of the disease. Prolactin mRNA in the anterior pituitary was decreased in the CSX and in the CSX/AA group but was not altered by AA. Plasma prolactin was raised in AA but T replacement did not reduce these elevated levels despite the absence of disease. Thus, prolactin provides a poor indicator of inflammation, suggesting that it may not be a potent pro-inflammatory compound in AA.
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PMID:A protective role for testosterone in adjuvant-induced arthritis. 860 51

Progesterone (P) stimulates prolactin secretion through a neural mechanism in estrogen (E)-primed female monkeys. Several peptides, including beta-endorphin (BE), oxytocin (OT), substance P (SP) and vasoactive intestinal polypeptide (VIP) are potential prolactin stimulatory factors and could mediate the effect of P. We hypothesized that the antagonism of a pivotal peptidergic neural system would block P-induced prolactin secretion and that the function of a pivotal peptidergic system would be altered by changes in gonadal steroid concentrations. Therefore it was of interest (1) to examine the effect of infusion of antagonists to these peptides on P-induced prolactin secretion, and (2) to determine BE, OT, SP and VIP levels in the hypothalamus of monkeys of various reproductive states. For the antagonist studies, female monkeys (n = 8) were spayed, adapted to a vest and tether remote sampling system and catheterized prior to antagonist challenges. E-primed monkeys received P injections 48 h prior to antagonist administration. Prolactin increased within 36-48 h of P injection. All antagonist challenges were administered in varying doses during the P-induced prolactin elevation and blood samples were collected every 10 min for prolactin determinations. The opiate antagonist, naloxone (n = 5), reduced serum prolactin in a dose-related manner with a mean IC50 of 1.5 +/- 0.6 micrograms/kg/min. The OT (n = 4), SP (n = 4) or VIP (n = 4) antagonists did not reduce serum prolactin in a dose-related manner. We previously reported that the hypothalamic content of OT is increased by ovarian hormones. To determine whether the hypothalamic content of BE, SP or VIP was related to gonadal status, the peptide levels in 4 hypothalamic regions of monkeys in various physiological states were measured. BE (ng/mg protein) in the medial basal hypothalamus (MBH) was significantly greater in adult females (17.7 +/- 6.9; n = 6) as compared to spayed females (0.6 +/- 0.2; n = 3) and juvenile females (1.8 +/- 1.1; n = 3). Hypothalamic content of SP in the preoptic area and mammillary bodies, but not the MBH, was significantly greater in gonadal intact females than spayed females. VIP content (pg/mg protein) was not significantly different between adult, spayed and juvenile females nor between adult and juvenile males in any hypothalamic area. Taken together these results support a pivotal role for BE in the neural regulation of P-induced prolactin secretion. The involvement of OT, SP, and VIP in a specific manner at the pituitary level is not indicated.
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PMID:Beta-endorphin, but not oxytocin, substance P or vasoactive-intestinal polypeptide, contributes to progesterone-induced prolactin secretion in monkeys. 879 99

Gonadal steroids have been implicated in the control of blood pressure and fluid homeostasis. These experiments test the effect of progesterone in ovariectomized ewes on blood pressure, volume, and hormone responses to hypotension. Eight ewes were each studied in four conditions: ovariectomized, progesterone and estrogen replaced, progesterone replaced, or sham treated. During each treatment mean arterial pressure (MAP), plasma volume (PV), baroreflex responsiveness, and adrenocorticotropic hormone (ACTH), arginine vasopressin (AVP), and renin responses to hypotension were determined. Progesterone treatment significantly reduced resting MAP and increased PV compared with ovariectomy or sham treatments. Heart period at 85 mmHg was reduced with progesterone treatment. There was no effect of progesterone treatment on ACTH, AVP, or renin or heart rate responses to hypotension. Basal AVP levels were increased, and angiotensin II concentrations were decreased, by estrogen and progesterone and by sham treatments; plasma Na+ also tended to be increased during these treatments. These results suggest that a small increase in progesterone can reset resting MAP and PV without altering reflex heart rate or endocrine responses to hypotension.
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PMID:Effects of progesterone on blood pressure, plasma volume, and responses to hypotension. 903 32

The effect of adrenocorticotropic hormone (ACTH) administration on progesterone and cortisol concentrations was determined in lactating primiparous sows. Physiological saline and 50 IU ACTH were administered on days 20 and 21 of lactation at 0900 hours via an indwelling jugular catheter. Blood samples for hormone analysis were collected via indwelling jugular catheters every 15 min (0800 to 1200 hours) and every 60 min (1300 to 1500 hours). Saline administration had no effect on progesterone nor cortisol concentrations in the lactating sows. Progesterone and cortisol concentrations increased (p < 0.001) within 15 min after ACTH administration. Progesterone and cortisol concentrations peaked (p < 0.01) within 45 min and had returned to pretreatment values within 120 min after ACTH treatment.
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PMID:Plasma levels of progesterone and cortisol after ACTH administration in lactating primiparous sows. 959 47

The paper contains a review of reports concerned with how for hormones, epileptic seizures and antiepileptic drugs can be influenced by one another. Hormones influence brain excitability but, on the other hand, both epileptic seizures and antiepileptic drugs may alter hormone secretion and metabolism. Effect of hormones on seizures--Experimental studies revealed the properties which inhibit or stimulate convulsive reactivity of different hormones. Progesterone, testosterone, adrenocorticotropin and desoxycorticosterone are responsible for an increase in seizure threshold, while estradiol, cortisol and thyroid hormones cause a reduction. Effect of seizures on hormones--Epileptic seizures, chiefly tonic-clonic, also complex partial and sometimes simple partial seizures, result in "the hormonal storm". Immediately after an epileptic seizure, an increase is found in serum concentrations of prolactin, cortisol, adrenocorticotropin, triidothyronine, thyroxin, thyrotropin, luteotropin, follicular stimulating hormone and growth hormone. These changes may persist for two hours, while prolactin concentration even for 24 hours after a seizure. Effect of antiepileptic drugs on hormones--Antiepileptic drugs may affect hypothalamus-pituitary function directly or indirectly through neurotransmitter system. By induction of hepatic microsomal enzymes, some antiepileptic drugs cause acceleration of hormone metabolism, reducing hormone serum concentrations. Moreover, antiepileptic drugs enhance sex hormone binding globulin SHBG/synthesis, increase binding of these hormones and reduce their active fraction concentration in serum. Recognition of the relationship between epilepsy and hormonal system is necessary to obtain better understanding of this disease.
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PMID:[Epilepsy and hormones]. 1076 43

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