Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The acute administration of 0.015-1.5 nmol ovine corticotropin-releasing factor (CRF) into the lateral ventricle of gonadectomized (or gonadectomized/adrenalectomized) female rats caused a rapid and prolonged dose-related inhibition of LH (but not FSH) secretion. By contrast, the acute peripheral injection of up to 15 nmol CRF was without effect in the same animal preparations. In cycling intact female rats, injection of 1.5 nmol CRF into the brain or of 75 nmol CRF sc inhibited ovulation and blocked the proestrous LH surge in about 50% of the animals. Lower doses of peripherally administered CRF were ineffective. Finally, CRF injected daily sc (15 nmol/day) to female rats during the first 12 days after mating caused a 40% disruption of pregnancy. These results indicate that CRF will lower plasma LH levels and can exert this effect in the absence of circulating steroids of either adrenal or gonadal origin. CRF inhibition of LH secretion, which we have previously reported to be absent in vitro, was unaltered by the opiate receptor antagonist naltrexone or by the ganglionic blocker chlorisondamine. Furthermore, blockade of CRF-induced beta-endorphin or ACTH release into the general circulation by dexamethasone did not interfere with the inhibitory effect of CRF on LH secretion. Such observations suggest that CRF exerts deleterious actions on reproductive functions through brain sites of action which, at least under the experimental mental design used, do not appear to directly involve opiate or peripheral catecholaminergic pathways.
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PMID:Influence of corticotropin-releasing factor on reproductive functions in the rat. 632 Nov 46

Effects of age and naloxone on testicular function were studied in golden hamsters exposed to short photoperiods. Subjection of hamsters to short photoperiods of 6 h light: 18 h darkness for 6 weeks led to testicular regression in young adult (5-6 months) or middle-aged (11-12 months) golden hamsters but not in prepubertal hamsters of 1-2 months of age. The middle-aged hamsters had decreased testis width by week 4 of treatment and the young hamsters by week 5. Daily injection of naloxone at the time of 'lights on' partially prevented testicular regression in young and middle-aged hamsters but the extent of regression was significantly greater in the middle-aged animals. Plasma LH and FSH concentrations were significantly reduced in hamsters placed in short photoperiods regardless of age or testicular weight, while naloxone treatment significantly increased the LH concentrations in all age groups. Plasma beta-endorphin-like immunoreactivity was significantly increased by short photoperiod or older age. These results indicated that (a) the sensitivity of the testicular suppression to short photoperiod increases as a function of age, (b) naloxone, a specific opiate receptor blocker, can partially prevent short photoperiod-induced testicular regression and (c) ageing and short photoperiods increase beta-endorphin-like immunoreactivity. It is concluded that the opiate system may be involved in ageing and photoperiod regulation of reproductive function.
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PMID:Age difference in endogenous opiate modulation of short photoperiod-induced testicular regression in golden hamsters. 632 8

The fetal porcine pituitary was investigated by means of ultrastructural immunocytochemistry (1) to identify the first cells synthesizing the adenohypophyseal hormones, (2) to follow their differentiation during fetal development, and (3) to compare their ultrastructural characteristics with those of mature adult cells. The first ACTH-cells, which produced and stored ACTH, beta-LPH, beta-MSH, and alpha- and beta-endorphin in the same granules, were very numerous at day 34 and displayed a uniform morphology. At day 50 and thereafter, until the end of gestation, the ACTH-cells differed in their appearance probably reflecting various stages of differentiation of one cell type. The GH-cells gained rapidly ultrastructural features comparable to those of mature GH-cells. In contrast, in the case of PRL-cells, which appeared only at the end of the gestation period as immature elements containing very small secretory granules, the morphological maturation seemed to take place only after birth. The first cells synthesizing the glycoprotein hormones (LH alpha, LH beta, FSH and TSH) displayed ultrastructural features of immature cells. At day 50, their ultrastructural organization started to show a different pattern. At the end of gestation, the TSH-cells and the gonadotropic cells displayed the ultrastructural features of mature cells.
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PMID:Functional differentiation of the anterior pituitary cells in the fetal pig. An ultrastructural immunocytochemical study. 632 16

Using immunoperoxidase techniques, the possible localization of pituitary regulatory peptides in fundic, antral and duodenal mucosae was investigated in both rat and man. All results obtained were similar in the two species. No glycopeptide (FSH, LH, TSH) was detected in the digestive tract. With different antisera directed against beta-lipotropin, alpha-MSH, beta-MSH, endorphins, ACTH 1-24, ACTH 17-39, a positive reaction was only obtained in the antral mucosae with an antiserum specific for the synthetic fragment 17-39 of ACTH. However neither the common precursor, proopiomelanocortin, nor the complete sequence of ACTH seem to be present in endocrine cells of the digestive tract. On the other hand, three antisera, directed against human growth hormone (GH), visualized numerous endocrine cells scattered in the glandular epithelium of the fundic and antral mucosae. Most cells were identified as ECL type in the gastric mucosae. Others are probably of the gastrin cell type in the antral mucosa, since these cells could be visualized on adjacent sections either with the antiserum against GH, or with a specific antiserum for gastrin.
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PMID:[Cytologic demonstration of immunoreactivity characteristic of adenopituitary peptides in the digestive epithelium of the rat and man]. 632 84

Patterning of plasma ACTH, beta-EP/beta-LPH and cortisol in response to ovine CRF (1 microgram/kg b.w.t. injected i.v.), was studied in three normal subjects and in five patients with Cushing's disease, two of whom had undergone total bilateral adrenalectomy. CRF caused in all subjects a prompt and concurrent rise of plasma hormone levels. The hormonal response was of the same magnitude in normal controls and in the three untreated Cushing's patients, but was much greater in the two adrenalectomized subjects. No changes were noted, after CRF, in plasma levels of GH, PRL, TSH, LH and FSH. These findings indicate that CRF specifically promotes the pituitary release of ACTH and ACTH-related peptides both in normal subjects and patients with Cushing's disease. In view of the likely CRF hypersecretion of the adrenalectomized patients, their ACTH and beta-EP/beta-LPH hyperresponsiveness to exogenous CRF would denote that the peptide does not down regulate its own pituitary receptors.
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PMID:Effect of CRF on the release of anterior pituitary hormones in normal subjects and patients with Cushing's disease. 632 64

We have investigated the in vitro and in vivo interactions of the four hypothalamic releasing factors, LHRH, corticotropin-releasing factor, TRH, and GH-releasing factor on anterior pituitary hormone secretions, using a 2 X 2 X 2 X 2 factorial experimental design. This experimental design allows for the evaluation of both the main treatment effects of the hypothalamic releasing factors as well as all of the possible interactions between them. Significant main treatment effects were: LHRH on LH and FSH, corticotropin-releasing factor on ACTH and beta-endorphin, TRH on TSH, and GH-releasing factor on GH. These results confirm the specificity of the four releasing factors on their respective target cells. There were no significant interactions between any of the releasing factors on anterior pituitary hormone secretions. These results suggest that the changes in pituitary secretion that are observed under physiological conditions are not due to interactions between the hypothalamic releasing factors at the level of the pituitary, but rather to other secondary interactions that modify pituitary activation or response. These results also indicate that the clinical pituitary reserve tests can be expanded to include all four hypothalamic releasing factors, since any lack of response will reflect a specific pituitary defect and not a failure to respond owing to interaction of the secretagogues administered.
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PMID:Multiple stimulation of the adenohypophysis by combinations of hypothalamic releasing factors. 632 31

The purpose of this study was to evaluate the effect of chronic immobilization on the hypophysial-adrenal and hypophysial-gonadal axes of adult male rhesus monkeys and the effect such manipulation has on the ability of these axes to respond to exogenous corticotropin, gonadotropin, and GnRH administration. A comparison was also made of the effects of immobilization on testosterone secretion at periods of low (April) and high (November) gonadal activity in this animal. Adult male rhesus monkeys were immobilized in a horizontal position for periods of up to 20 days during March/April. The function of the hypophysial-adrenal and hypophysial-gonadal axes was studied by monitoring plasma levels of cortisol, 17-hydroxylated precursors, 11 deoxycortisol, and testosterone during the period of restraint. Groups of immobilized and control animals also received iv injections of ACTH, FSH, and LH or LHRH on day 18 of the experiment. An additional group of animals was immobilized for 20 days, but did not receive exogenous hormone treatment. This group was used for comparison of seasonal differences in testosterone secretion with another group of animals subjected to the same treatment in November. During the first 3 h of immobilization, levels of cortisol, 17-hydroxylated precursors, and 11-deoxycortisol increased markedly from initial levels. Cortisol levels remained elevated for 3 days, whereas levels of the other three adrenal hormones declined to near-initial levels within 24 h. Testosterone levels declined steadily during the first 6 h of immobilization in males studied at a time of high testicular activity (November), while an increase during the first hour of restraint followed by a decline during the next 3 days were observed in males studied during a period of low testicular activity (April). Animals injected with ACTH on day 18 of immobilization had cortisol levels similar to those of control animals, but other groups of animals restrained for a similar period exhibited a lower level of plasma testosterone than controls after the injection of FSH and LH or LHRH. These data suggest that adaptation to stress results in a reduced demand for corticosteroid production and that the adrenals of chronically stressed animals are capable of responding to exogenous corticotropin, or alternatively, the immobilization imposed was stressful for only a limited time, and after a few days, animals no longer reacted as in response to stress. Also, secretion of testosterone in male monkeys is markedly influenced by the functional state of the gonads at the time of stress initiation.
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PMID:Levels of adrenal and gonadal hormones in rhesus monkeys during chronic hypokinesia. 632 44

Human GRF-(1-44)-NH2 (GRF-44) was administered iv in graded doses of 0.01-10 micrograms/kg to 35 normal young adult men and 38 women. GRF-44 stimulated the release of GH in a dose-dependent fashion, although the individual responses varied widely. The ED50 values for this effect were 0.4 micrograms/kg in men and 0.2 micrograms/kg in women in the midfollicular phase of the menstrual cycle. Maximal responses in men and women were not significantly different, and a dose of 1 micrograms/kg was sufficient to produce a maximal response. There was, likewise, no difference between responses of women tested in the midfollicular and midluteal phases of the cycle. There were no changes in PRL, LH, FSH, TSH, ACTH, beta-endorphin, or cortisol at doses up to 1 microgram/kg; at 10 micrograms/kg, PRL increased by an average of 7.6 ng/ml in the women. Side effects occurred in approximately 20% of both men and women at 1 microgram/kg and in nearly all subjects given 10 micrograms/kg; these consisted primarily of flushing and a sense of warmth. Thus, a dose of 1 microgram/kg GRF-44 is safe and effective, and would appear to be a reasonable choice for use in studying GH responses in normal subjects of other ages and in patients with disorders of GH secretion.
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PMID:Dose-response relationships for the effects of growth hormone-releasing factor-(1-44)-NH2 in young adult men and women. 633 Jan 51

The endocrine function of the hypophysial pars tuberalis is currently unknown. Recent immunocytochemical and electron microscopic studies have shown the presence of gonadotropin-producing cells in this tissue in intact rats. Because the pars tuberalis is not destroyed by hypophysectomy, the objective of the present study was to determine whether this gland is activated to produce pituitary hormones following hypophysectomy. Hormone-producing cells were identified by the unlabeled antibody peroxidase-antiperoxidase method of immunocytochemistry using primary antisera generated against the following hormones: LH, FSH, TSH, GH, PRL, ACTH, and beta-endorphin. In intact control rats, the only cell types detected in the pars tuberalis were gonadotropes and thyrotropes. Most gonadotropes contained both LH and FSH. The TSH cells were a separate cell population, and constituted the majority of pars tuberalis parenchymal cells. As early as 1 week after hypophysectomy, a hyperplastic and hypertrophic response was noted in the gonadotropes, and both cell types showed cytological features characteristic of enhanced hormonal synthesis and secretion. These responses increased with time post hypophysectomy. Secretory cell types not present in the pars tuberalis before hypophysectomy, i.e. somatotropes, mammotropes, opiocorticotrophes, were not activated or induced to differentiate after hypophysectomy. Based on these immunocytochemical observations, the hypophysectomized rat cannot be viewed as an animal totally devoid of anterior pituitary hormones. It has the capacity, or at least the potential, for secretion of LH, FSH, and TSH.
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PMID:Hormone production in the hypophysial pars tuberalis of intact and hypophysectomized rats. 640 Dec 46

The hypophysiotropic activities of a synthetic human pancreatic growth hormone releasing factor (hpGRF) with 40 residues was examined in vitro using rat pituitary halves. At concentrations from 10(-10) M to 10(-7) M the peptide stimulated GH release in a dose-dependent manner with the ED50 being 1.2 x 10(-9) M. The concentration of 10(-10) M hpGRF is comparable to the basal hypophyseal portal blood levels of other known hypothalamic hypophysiotropic hormones. However, GH release was enhanced three-fold by concentration as low as 10(-12) M, though no dose-response relationship was observed up to 10(-10) M. Thus, this peptide not only stimulates the release of GH in a dose-dependent manner, but at lower concentrations also maintains elevated GH levels. The release of ACTH, beta-endorphin, LH, and FSH was not affected by hpGRF at any of the concentrations tested. At hpGRF concentrations less than 10(-7) M, the release of TSH and PRL were unaffected. However, at 10(-6) M, TSH release was enhanced about 2.5 fold and prolactin release was elevated slightly.
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PMID:In vitro pituitary hormone releasing activity of 40 residue human pancreatic tumor growth hormone releasing factor. 640 22


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