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 regional distribution and relative concentrations of LHRH and beta-endorphin immunoreactivity in the hypothalamus were compared in sexually active and sexually inactive Soay rams. LHRH was localized principally in the medial basal hypothalamus and median eminence with lower concentrations in the anterior hypothalamus and preoptic area. beta-endorphin immunoreactivity was also found in highest concentrations in these regions but was more widely distributed into the rostral, dorsal and lateral parts of the hypothalamus. LHRH content in the medial basal hypothalamus was significantly lower in the sexually active rams compared to inactive rams while there was no difference in beta-endorphin immunoreactivity content between the two groups. Gel filtration chromatography of hypothalamic extracts revealed that the beta-endorphin immunoreactivity was due to both beta-lipotropin and beta-endorphin; the ratio of beta-endorphin: beta-lipotropin tended to be less in the sexually active rams than in the sexually inactive rams. The results are consistent with the hypothesis that beta-endorphin is a physiologically important endogenous opioid involved in the modulation of LHRH secretion.
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PMID:LHRH and beta-endorphin in the hypothalamus of the ram in relation to photoperiod and reproductive activity. 297 10

Ovine corticotropin-releasing factor (oCRF) stimulates increased plasma immunoreactive adrenocorticotropin (IR-ACTH) and IR-cortisol at threshold, half-maximal, and maximal doses of 0.01-0.03, 0.3-1, and 3-10 micrograms/kg, respectively. Side effects occur with increasing frequency, severity, and duration at doses above 1 microgram/kg. oCRF has a prolonged duration of action, at least in part because of the long circulating half-life of intact oCRF in plasma. Increasing doses of oCRF given in late afternoon progressively diminish the next morning's circadian rise in plasma IR-ACTH in normal subjects, but not in Addisonian patients or subjects receiving metyrapone, indicating that prolonged oCRF-induced hypercortisolemia is the cause. Plasma IR-lipotropins and IR-beta-endorphin rise and fall concomitantly with IR-ACTH after oCRF injection. Arginine vasopressin increases the IR-ACTH response to oCRF fourfold when given simultaneously with oCRF. Cushing's disease patients respond variably, suggesting that oCRF may not be a very useful diagnostic agent in Cushing's syndrome. However, the combination of oCRF with growth hormone-releasing factor, gonadotropin-releasing hormone, and thyrotropin-releasing hormone appears to provide a rapid and useful test of combined anterior pituitary function.
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PMID:Clinical studies with synthetic ovine corticotropin-releasing factor. 298 41

The antigonadal activity of potent gonadotropin-releasing hormone (GnRH) analogs may be associated with undesirable secondary effects on other aspects of the endocrine system. In preliminary studies, rats treated with GnRH agonists were noted to have altered adrenal weights. To determine whether this was associated with alterations in the pituitary-adrenal axis we have studied male and female rats treated with the GnRH agonist [(imBzl)-D-His6, Pro9-NEt]-GnRH (GnRH-A). Animals receiving daily doses of this peptide showed normal adrenal corticosteroid responsivity to both ether and immobilization stress. Brain, pituitary, and plasma concentrations of immunoreactive (IR) beta-endorphin and ACTH were unaffected in treated animals after four weeks of daily injections, although after one week plasma levels of the two hormones were transiently elevated in female rats. Adrenal, thyroid, and pituitary lobe weights were unchanged with treatment, except for an increase in anterior pituitary weight in males receiving the lowest dose of GnRH-A. In conclusion, long-term treatment with GnRH-A, while significantly affecting gonadal and secondary sexual tissue, had little impact on the hypothalamo-pituitary-adrenal system or on stress responsivity in rats.
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PMID:The effects of the GnRH agonist, [(imBzl)-D-His6, Pro9-NEt]-GnRH, on the response to stress in rats. 298 31

Within the past year, three similar peptides with specific growth hormone (GH) releasing effects have been extracted from human tissue, identified, and synthesized. Human pancreatic tumor GH releasing factor (I-40)-OH (hpGRF-40) was the sole hpGRF isolated from the pancreatic tumor of a patient in Charlottesville and was the predominant peptide isolated from the pancreatic tumor of a patient in Lyon. The Lyon tumor also contained hpGRF(1-37)-OH and hpGRF(1-44)-NH2. Both immunological and biochemical data suggest that hpGRF-40 and hpGRF-44 are present in the human hypothalamus and may be the human GH releasing hormone(s) (GHRH). In cultures of rat pituitary cells, hpGRF stimulates GH but affects neither basal and dopamine-inhibited prolactin release nor basal and gonadotropin releasing hormone (GnRH)-stimulated luteinizing hormone (LH) release. hpGRF stimulates cyclic AMP production within seconds, an effect which is blocked by somatostatin. In contrast, while hpGRF stimulates phosphatidylinositol turnover in the pituitary, the effect is not inhibited by somatostatin. In the human, hpGRF-40 (1 microgram/kg) given intravenously (i.v.) stimulates GH release within 5 minutes. hpGRF-40 does not elevate serum prolactin levels, thyrotropin (TSH), LH, or corticotropin (measured indirectly through plasma cortisol), or blood glucose or plasma concentrations of insulin, glucagon, pancreatic polypeptide, cholecystokinin, gastrin, gastric inhibitory peptide, motilin, or somatostatin. When graded doses of hpGRF (0.1-10 micrograms/kg) are given i.v., no differences are noted in the maximal levels of serum GH achieved.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Human pancreatic tumor GH-releasing factor. 298 23

Recent studies indicate that proopiomelanocortin (POMC)-derived peptides are present in the testis and may be involved in the regulation of gonadal function, although their precise role still remains obscure. In the present study, we investigated in the rat whether testicular interstitial fluid (TIF), a functionally important compartment of the testis, contains POMC-derived peptides. Adult rats were used for all the experiments, and TIF was collected from each individual testis and analyzed for the presence of ACTH and beta-endorphin-like immunoreactivity (beta end-LI). Initial studies indicated that both ACTH and beta end-LI can be readily detected in TIF from intact rats, and that the concentrations of these peptides are severalfold higher than those in the peripheral plasma of the same animals. Similar studies in rats 3-5 days after hypophysectomy indicate that although ACTH and beta end-LI levels in plasma were undetectable, high levels of both peptides were measured in TIF. Moreover, serial dilution curves of TIF showed parallelism with the respective standard curves in the beta end and ACTH assays. Additional studies indicated that levels of POMC peptides in TIF were modified by treatments that affect the endocrine function of the testis. In that respect, hCG given sc to hypophysectomized rats increased testosterone levels in TIF and plasma, and similarly increased beta end-LI concentrations in TIF. A LHRH analog (LHRH-A; [D-Ala6,des-Gly10]LHRH-ethylamide) given sc to hypophysectomized rats resulted in increased testosterone production, but decreased beta end-LI in TIF, suggesting that the effects of hCG and LHRH-A on testicular beta end-LI secretion are not directly coupled with testosterone production. Prolonged treatment of intact rats with the LHRH-A for 2-10 days resulted in progressive declines in testicular weight and testosterone levels in TIF and in plasma, and a significant suppression of beta end-LI levels in TIF as early as 2 days after analog treatment. On the other hand, acute intratesticular injection of LHRH-A to intact rats (5 ng into the right testis) produced a short-lived increase in beta end-LI in TIF 2 h after injection, coincident with a temporary decrease in TIF volume. These results indicate that the POMC-derived peptides ACTH and beta end are present in TIF and are secreted locally into this compartment, supporting previous reports demonstrating the presence and local synthesis of POMC peptides in testicular tissue.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Proopiomelanocortin-derived peptides in testicular interstitial fluid: characterization and changes in secretion after human chorionic gonadotropin or luteinizing hormone-releasing hormone analog treatment. 300 Jul 42

A circannual analysis was made of serum cortisol, luteinizing hormone (LH), and testosterone concentrations in the male clouded leopard (Neofelis nebulosa). Group I males (n = 4), maintained in a standardized environment, were bled serially during a regimented anesthesia/electroejaculation episode occurring monthly (beginning in January, ending in December). Additional sampling intervals were conducted under anesthesia only (control, n = 8), anesthesia plus a single adrenocorticotropin hormone challenge (ACTH, Cortrosyn, n = 4), or anesthesia plus a single 25 micrograms injection of gonadotropin-releasing hormone (GnRH, Gonadorelin, n = 4). Group II males (n = 6) from various zoological collections were sampled serially under the same semen collection conditions on one random occasion within the year. Serum cortisol levels were 2 times greater than values measured in comparable studies involving other felid species. Cortisol concentrations were similar during electroejaculation and control (anesthesia only) episodes, and mean levels did not rise as a result of semen collection. Adrenocorticotropin caused an immediate rise in cortisol to levels at least 1.5 times greater than electroejaculated or control counterparts. Mean concentrations of basal cortisol in individual males gradually increased as the year progressed, possibly as a consequence of repeated psychogenic stress. Between seasons, there were no differences in mean LH; however, testosterone levels were greater (p less than 0.05) in the winter compared to all other seasons. There were no differences (p greater than 0.05) between individual males in secretory patterns or mean concentrations of cortisol, LH, or testosterone. Within males, distinct temporal fluctuations were observed in both LH and testosterone during the approximately 80-min sampling interval. Neither LH nor testosterone profiles appeared affected by cortisol patterns during electroejaculation or after an ACTH challenge. A bolus of GnRH induced a marked rise in serum LH and testosterone within 15 and 30 min respectively, indicating that these two hormones were coupled. Both LH and testosterone profiles in Group II males mimicked those in Group I; concentrations of cortisol in Group II males immobilized on one occasion were similar to those of Group I animals sampled from January-May but appeared to be less than values measured from June-December. These data demonstrate that the clouded leopard, compared to other felids, produces markedly elevated concentrations of cortisol, which are likely related to an aggressive behavioral temperament.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Reproductive physiology of the clouded leopard: II. A circannual analysis of adrenal-pituitary-testicular relationships during electroejaculation or after an adrenocorticotropin hormone challenge. 301 73

Female rats were treated with two intraventricular injections each of 350 micrograms 6-hydroxydopamine (6-OHDA) and used for experiment 4 or 14 days later. The response to laparotomy, as assessed by subsequent in vitro corticosterone release, was unaffected by the drug, but that to the smaller stress of a skin cut was significantly reduced. Both fast and delayed feedback responses to corticosterone administration were still evident in 6-OHDA-treated animals. When determined 14 days after treatment, hypothalamic concentrations of epinephrine (E) and norepinephrine (NE) were reduced by 46 and 84%, respectively. There was no significant change in content of immunoreactive corticotropin-releasing factor (CRF-41). The acetylcholine-stimulated release of CRF bioactivity from control hypothalami incubated in vitro was significantly inhibited by E or NE, with E being at least 10 times more potent on a molar basis. This effect of NE was enhanced in hypothalami removed from 6-OHDA-treated rats, complete inhibition of acetylcholine-stimulated release of CRF being produced by 0.6 nM NE, as opposed to 6.0 nM for untreated controls. At the level of the anterior pituitary gland, tissue content of adrenocorticotropin (ACTH) was unaffected by treatment, but that of luteinizing hormone (LH) in the same tissues was significantly increased. The corticotrophic response of fragments of the gland incubated or perifused in vitro to hypothalamic extract, CRF-41, arginine vasopressin or E was reduced. In contrast, the response of the tissue to gonadotropin-releasing hormone (GnRH) added in vitro was not significantly affected.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effects of 6-hydroxydopamine on the hypothalamo-pituitary-adrenocortical axis. 301 9

IPL nude females present an absence of lactation with hypoprolactinemia. While males present a slight but significant decrease in serum testosterone and gonadotropins, females show normal values of estradiol, progesterone, LH and FSH during all estrus cycle stages. In this work, we observed that the postovariectomy rise of LH and FSH was significantly lower in the IPL nude females. We studied also the effect of acute (1 injection of 25 micrograms/rat E2Bz) or long-term (E2Bz capsule for 8 days) estradiol benzoate (E2Bz) treatment, with or without progesterone injection (5 mg/rat) in ovariectomized (OVX) IPL and normal females. The sensitivity of gonadotropins to E2 negative feedback is decreased in the IPL nude rats, result in agreement with previous reports and which could be linked to both hypoprolactinemia and decreased beta-endorphin observed in the IPL nude rat. The responsiveness of LH to LHRH was also tested in OVX and OVX + E2Bz or OVX + E2B + P treated. In OVX females responsiveness of LH to LHRH was similar in IPL nude to that of normal females. However, LH responsiveness in acute and long-term steroid-treated OVX IPL nude was significantly depressed. Since the mechanism whereby PRL interacts with steroids to modify gonadotropin secretion is still unexplained, IPL nude rat could be a good model to study it.
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PMID:Steroid regulation of gonadotropins in genetically hypoprolactinemic females (IPL nude rats). 308 74

There are few reports of spontaneous pregnancies in patients with Sheehan's syndrome. We describe two cases which exhibited adrenal and thyroid insufficiency but not amenorrhea, return of the menstrual periods being at the expected time after delivery. Endocrinologic studies confirmed thyrotropin and corticotropin insufficiency. Clinical evidence of preserved gonadotropin secretion was supported by the response of LH and FSH to acute administration of synthetic LHRH and by the fact that thyroid and corticoid hormonal replacement resulted in a spontaneous pregnancy with successful outcome.
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PMID:[Sheehan's syndrome followed by spontaneous pregnancy. Apropos of 2 cases]. 309 24

This short review discusses the gonadotropin-releasing hormone 'pulse generator' in the female rhesus monkey and the important modulatory role which the endogenous opioid peptides exert in the control of its activity. Also discussed is the modulation of opioid peptide release by ovarian steroids and corticotropin-releasing hormone.
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PMID:A role for the endogenous opioid peptides in the regulation of gonadotropin secretion in the primate. 313 66


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