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)

Central administration of neurotensin (NT) has been shown to activate the hypothalamic-pituitary-adrenal axis, an effect which seems dependent upon the release of corticotropin-releasing factor. In this study, we describe the distribution of NT binding sites in the hypothalamus using film and emulsion receptor autoradiography. Among the 125I-NT-labelled hypothalamic nuclei, relatively high densities of neurotensin binding sites were detected over the paraventricular nucleus. Silver grains on emulsion-coated slides overlaid indiscriminately cell bodies and surrounding processes of magnocellular and parvocellular parts of the nucleus. Two newly developed NT receptor antagonists, SR 48692 and its analog SR 48450, competed for 125I-NT binding to hypothalamic tissue sections and membrane preparations with Ki values in the nanomolar range. Moreover, intracerebrally injected SR 48450 was able to block the NT-induced hypothalamic-pituitary-adrenal axis activation in freely moving rats, whereas its administration alone did not significantly affect basal plasma levels of adrenocorticotropin and corticosterone. These data provide anatomical substrate for a potential neurotensin action at the hypothalamus in the hypothalamic-pituitary-adrenal axis activation and highlight the use of new non-peptide NT receptor antagonists to characterize the effects of NT on neuroendrocrine functions.
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PMID:Blockade of neurotensin binding in the rat hypothalamus and of the central action of neurotensin on the hypothalamic-pituitary-adrenal axis with non-peptide receptor antagonists. 808 81

We have previously reported the presence of authentic pro-TRH-derived peptides in cultured anterior pituitary (AP) cells. The present studies were undertaken to determine whether pro-TRH mRNA could be demonstrated in the AP and to elucidate the cell type expressing pro-TRH. AP cells were cultured for up to 18 days, during which time the content of both TRH and prepro-TRH-(25-50) rose significantly (P < 0.01). In contrast, the cellular contents of LH, FSH, TSH, and ACTH fell significantly (P < 0.01), whereas that of GH increased by 45.9% (P < 0.05). Northern blot analysis revealed that the levels of pro-TRH mRNA extracted from AP cells (18 days in culture) were similar to those in hypothalamic tissue from adult male rats, indicating a high relative abundance of this mRNA in the AP. In situ hybridization experiments showed a dense accumulation of silver grains over a subpopulation of cultured AP cells. A combination of in situ hybridization for pro-TRH mRNA and immunocytochemistry for pituitary hormones revealed colocalization of pro-TRH mRNA and GH in a subpopulation of somatotrophs. No colocalization with LH-, TSH-, PRL-, or beta-endorphin-containing cells was observed. Immunocytochemistry at the electron microscopic level demonstrated that prepro-TRH-(25-50) was contained in a subpopulation of secretory granules in AP cells expressing this pro-TRH-derived sequence. These studies demonstrate that pro-TRH mRNA is present in cultured AP cells in high concentration and that the pro-TRH gene is expressed within a subpopulation of somatotrophs.
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PMID:Thyrotropin-releasing hormone (TRH) gene expression in the anterior pituitary. I. Presence of pro-TRH messenger ribonucleic acid and pro-TRH-derived peptide in a subpopulation of somatotrophs. 829 76

Proopiomelanocortin (POMC) is the precursor of the potent opioid peptide beta-endorphin as well as a number of other active peptides. On the basis of neuroanatomical data indicating the presence of contacts between POMC neurons in the rat arcuate nucleus, it has been proposed that POMC neurons could be autoregulated. In order to investigate the role of opiates in the regulation of POMC gene expression in the rat arcuate nucleus, we studied the effects of chronic administration of the opioid drug morphine and an opiate receptor antagonist naloxone on POMC mRNA levels as measured by in situ hybridization, 4-day treatment with naloxone (4 mg/kg/day) produced a 60% increase in the number of silver grains overlying POMC neurons. Conversely, morphine (40 mg/kg/day) also administered during 4 days decreased the hybridization signal by 30%. The concomitant administration of morphine and naloxone completely prevented the effect of morphine on POMC gene expression indicating that the inhibitory influence of morphine is likely to be mediated by opioid receptors. The data obtained clearly indicate that activation of opioid receptors decreased the biosynthetic activity of POMC neurons and that conversely opiate receptor blockade caused an increase in the activity of these neurons. They are consistent with the hypothesis of an autoregulation of the POMC neuronal system by endogenous opiate peptide(s).
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PMID:Opioid regulation of proopiomelanocortin (POMC) gene expression in the rat brain as studied by in situ hybridization. 841 62

The development of endocrine cells in the chicken proventriculus has been investigated using light- and electron-microscopy in conjunction with silver and immunocytochemical techniques. The first morphologically detectable endocrine cells were found in 5-day-old embryos by electron microscopy. From the 9th to the 13th day, endocrine cells in contact with the lumen of the organ could be detected both by electron and light (silver impregnation) microscopy. The number of open-type endocrine cells progressively decreased and the number of closed-type increased after this stage. Until the 16th day, endocrine cells were located exclusively in the luminal epithelium, but afterwards they appeared in progressively greater numbers in the compound glands. After hatching, long cytoplasmic processes could be seen in the endocrine cells. Immunoreactivities to regulatory substances appeared in the following order: serotonin (day-14), avian pancreatic polypeptide, glucagon and somatostatin (day-16), bombesin and neurotensin (day-18), and finally, met-enkephalin (day-21).
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PMID:Development of the diffuse endocrine system in the chicken proventriculus. 844 27

We studied the cortisol level in blood serum and adrenal homogenates, as well as the in vitro production of cortisol in adrenals of silver fox embryos of both sexes in response to exogenous adrenocorticotropic hormone (ACTH) stimulation. The level of cortisol in blood serum did not show any significant changes during the embryo development, while its level in adrenals and production by adrenals in vitro increased progressively from Day 35 to Day 50 of prenatal life. We found that ACTH is capable of stimulating cortisol biosynthesis and production in vitro during all studied periods of embryogenesis.
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PMID:[The biosynthesis of cortisol and its regulation by the adrenocorticotropic hormone in the adrenals of silver fox embryos]. 875 26

There is compelling evidence that endogenous opioid peptides are regulated by exogenous opiates. Our previous studies have shown that the mu-opioid receptor protein and mRNA are down-regulated in the mediobasal hypothalamus of the female guinea pig following chronic morphine treatment. In addition, electrophysiological studies have shown that hypothalamic beta-endorphin (beta-EP) neurons express mu-opioid receptors that are uncoupled and down-regulated following chronic morphine treatment. Currently, we tested the hypothesis that chronic morphine, which produces down-regulation of mu-opioid receptors, causes a down-regulation of pro-opiomelanocortin (POMC, the precursor of beta-EP) mRNA expression in female guinea pig hypothalamus. Female guinea pigs were ovariectomized and implanted subcutaneously (s.c.) with 4 x 75 mg pellets for 2 days plus six more pellets of either morphine (n = 6) or placebo (n = 6) for another 5 days. Animals were sacrificed between 1000 and 1100 h on day 7. The expression of POMC mRNA were investigated using in situ hybridization histochemistry with a guinea pig specific 35S-labeled cRNA probe in hypothalamic tissue sections. POMC mRNA was localized to the arcuate nucleus (Arc) and median eminence (ME) of the medial basal hypothalamus. The distribution pattern was the same in both morphine and placebo control animals. However, the density of silver grains was less in morphine treated animals versus placebo control animals. Overall, the level of POMC mRNA was decreased by 22% in the Arc of morphine-treated guinea pigs as compared with the placebo controls (p < 0.05). This decrease in POMC mRNA expression was even greater in the caudal Arc (28%, p < 0.01) in morphine-treated animals. These results suggested that the biosynthetic activity of POMC neurons is down-regulated with chronic exposure to morphine.
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PMID:Proopiomelanocortin (POMC) mRNA expression: distribution and region-specific down-regulation by chronic morphine in female guinea pig hypothalamus. 964 54

In golden hamsters, seasonal changes in day length act via a pineal-dependent mechanism to regulate feedback and behavioral effects of androgen. Endogenous opiates participate in photoperiodically regulated neuroendocrine functions, but the effects of androgen on expression of the gene encoding POMC, the precursor of beta-endorphin, have been controversial. We used quantitative in situ hybridization to examine regulation of POMC messenger RNA (mRNA) by testosterone and to test the hypothesis that short day lengths act through the pineal gland to amplify POMC mRNA expression. We studied intact hamsters and castrates with or without androgen treatment held in long (14 h of light, 10 h of darkness) or short (5 h of light, 19 h of darkness) days for 10 weeks. POMC gene expression differed with rostral-caudal plane, photoperiod, and surgical treatment (castration and testosterone administration). Testosterone increased the number of silver grains in labeled cells throughout the arcuate nucleus, and short day castrates given androgen consistently had more silver grains per labeled cell than did their long day counterparts. Testosterone exerted an inhibitory effect, however, on the number of POMC mRNA-positive cells, and more POMC mRNA-labeled cells were found in the arcuate nucleus of long than short day castrates treated with testosterone. Photoperiod had no significant influence in castrates not receiving androgen. Testosterone treatment had generally similar effects whether it was begun at the time of castration or 5 weeks later. Pinealectomy blocked the influence of photoperiod on both the mean number of silver grains per labeled cell and the number of labeled cells. The results indicate that day length regulates POMC gene expression when androgen levels are held constant, but that androgen is necessary for photoperiod effects to be expressed.
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PMID:Effects of photoperiod and androgen on proopiomelanocortin gene expression in the arcuate nucleus of golden hamsters. 988 26

The present study investigated the effects of acute administration of cyanamide (a potent inhibitor of aldehyde dehydrogenase used to treat alcoholics), on the hypothalamo-pituitary adrenal (HPA)-axis. Cyanamide resulted in a significant increase in arginine vasopressin mRNA and corticotrophin releasing factor (CRF) mRNA in the parvocellular cells of the paraventricular nucleus and pro-opiomelanocortin (POMC) mRNA in the anterior pituitary. Plasma corticosterone concentrations were elevated by a range of doses of cyanamide which were maintained in the high dose group at 4 h following administration. These results suggest that cyanamide is able to activate the HPA axis at all levels of the axis. Arginine vasopressin mRNA, in the parvocellular cells of the paraventricular nucleus is an important component of the stress response. Silver grain counting of emulsion dipped slides is commonly used for its evaluation following in-situ hybridization. This method is however, not entirely satisfactory and very time-consuming. We compared this method with a film autoradiographic method, and show that the film autoradiographic method is valid for the determination of arginine vasopressin mRNA in the parvocellular cells of the paraventricular nucleus.
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PMID:Cyanamide-induced activation of the hypothalamo-pituitary-adrenal axis. 1071 21

Sheep experience well-documented seasonal changes in reproductive activity and voluntary food intake (VFI). Within the hypothalamus, neurones that express neuropeptide Y (NPY) and pro-opiomelanocortin (POMC) have been implicated in the regulation of reproduction and appetite. In this study, we aimed to determine the extent to which the expression of these two neuronal systems is linked to the seasonal reproductive cycle and/or the seasonal appetite cycle. VFI in our sheep reaches a nadir in August with no difference occurring between December and February. We examined the brains of ovariectomized (OVX) female sheep (n=5-7) that were killed during the breeding season (February) or during the early or late nonbreeding season (August and December, respectively). The brains of these animals were perfused with paraformaldehyde and processed for in situ hybridization histochemistry, using ribonucleotide probes labelled with 35S. The number of NPY and POMC cells and the number of silver grains per cell were counted using an image analysis system. For NPY, the number of cells counted in the arcuate nucleus/median eminence region and the number of silver grains per cell was significantly lower in animals killed during August than in animals killed in February or December. The number of grains per cell over NPY cells was also significantly lower in animals killed during August. For POMC, the number of cells was lower in February than in August and December. Similarly, the number of grains per cell for POMC were lower in February than in August and December. VFI was significantly lower in animals during August than at other times of the year. We conclude that in OVX ewes: (i) NPY gene expression is lower at the time of the year when VFI is reduced and (ii) POMC gene expression is greater at the time of the nonbreeding season than during the breeding season. Because these results were obtained in OVX animals, the changes appear to be independent of alterations in the secretion and/or action of ovarian steroids. Thus, the activity of NPY neurones appears to relate to changes in appetite whereas changes in POMC expression may be relevant to the seasonal breeding cycle.
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PMID:Seasonal changes in the expression of neuropeptide Y and pro-opiomelanocortin mRNA in the arcuate nucleus of the ovariectomized ewe: relationship to the seasonal appetite and breeding cycles. 1106 26

The gut of silver eels (Anguilla anguilla L.) was investigated in order to describe both the cholinergic and adrenergic intramural innervations, and the localization of possible accessory neuromediators. Histochemical reactions for the demonstration of nicotinamide adenine dinucleotide phosphate, reduced form-(NADPH-)diaphorase and acetylcholinesterase (AChEase) were performed, as well as the immunohistochemical testing of tyrosine hydroxylase, met-enkephalin, substance P, calcitonin gene-related peptide (CGRP), bombesin, vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), somatostatin, cholecystokinin-octapeptide (CCK-8), serotonin, cholineacetyl transferase. The results evidenced a different pattern in comparison with other vertebrates, namely mammals, and with other fish. Both NADPH-diaphorase and AChEase activities were histochemically detected all along the gut in the myenteric plexus, the inner musculature and the propria-submucosa. Tyrosine hydroxylase immunoreactivity was observed in the intestinal tract only, both in the myenteric plexus and in the inner musculature. Several neuropeptides (metenkephalin, CGRP, bombesin, substance P, VIP, NPY, somatostatin) were, in addition, detected in the intramural innervation; some of them also in epithelial cells of the diffuse endocrine system (met-enkephalin, substance P, NPY, somatostatin). Serotonin was only present in endocrine cells. Tyrosine hydroxylase immunoreactivity was present in localizations similar to those of NADPH-diaphorase-reactivity, and in the same nerve bundles in which substance P- and CGRP-like-immunoreactivities were detectable in the intestinal tract. In addition, NADPH-diaphorase-reactive neurons showed an anatomical relationship with AChEase-reactive nerve terminals, and a similar relationship existed between the latter and substance P-like immunoreactivity.
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PMID:Neurotransmitters and putative neuromodulators in the gut of Anguilla anguilla (L.). Localizations in the enteric nervous and endocrine systems. 1109 1


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