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 present study was undertaken to determine the structure-activity relationships of ACTH analogs on corticosteroid production by frog adrenal gland. Rana ridibunda interrenal dice were perifused with amphibian culture medium for 10 hr. Corticosterone and aldosterone concentrations were measured in the effluent perifusate using sensitive and specific radioimmunoassay methods. Perifusion of interrenal fragments with increasing concentrations of synthetic human ACTH 1-39 (ranging from 6.25 X 10(-11) to 10(-9) M) led to a linear log-dose increase in both corticosterone and aldosterone secretion. Thus, this model made it possible to compare the steroidogenic potency of several ACTH analogs. Synthetic alpha-MSH and its des-N alpha-acetyl derivative were found to be approximately equipotent, and 5 X 10(3) times less active than authentic ACTH. The short-chain analog ACTH 1-10 was 2 X 10(4) times less potent than ACTH whereas ACTH 4-10 was totally inactive. A fragment of the N-terminal region of the proopiomelanocortin molecule, gamma 3-MSH, caused a dose-related stimulation of steroid secretion. However, in contrast to what has been observed in the rat, gamma 3-MSH did not potentiate the corticotropic action of ACTH on frog interrenal gland. Since processing of proopiomelanocortin in frog intermediate lobe generates high amounts of alpha-MSH and des-N alpha-acetyl alpha-MSH, these results suggest that in amphibians, several peptides other than ACTH may be involved in the control of corticosteroidogenesis.
Gen Comp Endocrinol 1986 Feb
PMID:In vitro study of frog (Rana ridibunda Pallas) interrenal function by use of a simplified perifusion system. VIII. Structure-activity relationship of synthetic ACTH fragments and gamma-MSH. 300 66

Unlike tetrapod ACTH cells, teleost ACTH cells do not react with the periodic acid-Schiff method (PAS). To find an explanation for this unique feature, chromatographic fractions obtained after filtration of pituitary extracts of Prochilodus platensis in Sephadex were immunologically analyzed. A high-molecular-weight protein which was identified as pro-opiomelanocortin (POMC) was detected. When this POMC was submitted to affinity chromatography in concanavalin binding, it was not detected. Furthermore, pituitaries incubated in media containing [3H]glucosamine or [3H]fucose did not incorporate these amino acids to the newly synthesized POMC. The results obtained strongly suggest an inability of the fish to glycosilate POMC, and this failure could account for the PAS-negative reaction in the ACTH cells.
Gen Comp Endocrinol 1986 Feb
PMID:Lack of glycosilation of pro-opiomelanocortin might account for the periodic acid-Schiff-negative reaction in ACTH cells of teleost fishes. 300 68

Antisera raised against chum salmon prolactin (PRL), trout growth hormone (GH), mammalian adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), luteinizing hormone (LH), and alpha-melanophore-stimulating hormone (alpha-MSH) were used to localize PRL, GH, ACTH, gonadotropic, TSH, and MSH cells in the hypophysis of the teleost Dicentrarchus labrax using the unlabeled peroxidase anti-peroxidase method. In the rostral pars distalis, ACTH cells stained very intensively with anti-ACTH; so did the MSH cells in the pars intermedia. The prolactin cells stained very specifically with anti-prolactin without staining the growth hormone cells. In the proximal pars distalis anti-GH, anti-TSH beta, and anti-LH stained selectively the corresponding cells; with these antisera no cross-reaction with any other cell type was observed. Anti-alpha-MSH only stained cells in the pars intermedia. Some cells in the pars intermedia did not react at all; these could correspond to the PAS-positive cells. A characteristic feature was positive staining with anti-LH in some cell groups encircling the pars intermedia, indicating the fact that in the seabass some cells of the proximal pars distalis surround the pars intermedia.
Gen Comp Endocrinol 1986 Mar
PMID:Immunocytochemical identification and localization of the different cell types in the pituitary of the seabass (Dicentrarchus labrax). 300 72

The ability of corticoliberin (CRF), urotensin I, sauvagine, arginine-vasopressin (AVP), and mesotocin to stimulate ACTH release by frog anterior pituitary cells and alpha-melanotropin (MSH) by frog neurointermediate lobe was studied in vitro using a perifusion technique. CRF and AVP were found to be potent stimulators of ACTH secretion, whereas urotensin I and sauvagine were totally inactive. In opposition to recent findings in the rat. CRF did not modify alpha-MSH secretion by the frog neurointermediate lobe. Mesotocin, which is present in the parenchymal cells of the frog pars intermedia, had no effect on alpha-MSH release in vitro. No potentiation of CRF-induced ACTH release was observed when anterior pituitary cells were incubated with a combination of AVP and CRF. Together with the recent elucidation of a CRF-like molecule in the frog diencephalon, these results suggest that, in Amphibia, CRF and AVP exert their stimulatory action specifically on distal lobe corticotrophs.
Gen Comp Endocrinol 1986 Mar
PMID:Comparative effects of corticotropin-releasing factor, arginine vasopressin, and related neuropeptides on the secretion of ACTH and alpha-MSH by frog anterior pituitary cells and neurointermediate lobes in vitro. 300 73

The distribution and nature of ACTH-related material in the pituitary gland of chinook salmon (Oncorhynchus tschawytscha) was studied. Pars distalis (PD) and neurointermediate lobe (NIL) extracts were analyzed by gel filtration on BioGel P6 and the resultant fractions assayed for ACTH immunoreactivity (ACTH-IR) using six different antibodies, all of which were specific for ACTH when applied to mammalian samples, and for alpha-MSH. In the PD a number of distinct peaks of ACTH-IR were observed, which were detected to different degrees by the different ACTH antibodies. Three of the ACTH antibodies produced essentially similar results. The other ACTH antibodies produced results quite distinct from these, and distinct from one another. Thus ACTH-IR is present in the salmon PD in a number of distinct forms, all of which appear to have molecular weights between about 2000 and 5000. No alpha-MSH was detected in the PD. All of the ACTH antibodies also detected material in the NIL. In general the different antibodies produced similar results. There were fewer peaks of ACTH-IR in the NIL than in the PD. The major one of these, which eluted between the void volume and 1-39 ACTH, was detected by all the antibodies. One of the antibodies also detected a peak of ACTH-IR which eluted close to where alpha-MSH eluted. All of the ACTH antibodies detected more material in the PD than in the NIL, the ratio being about 3:1 in every case. alpha-MSH-IR eluted as a minor peak at the void volume, and a major peak in the position of authentic 1-13 alpha-MSH.
Gen Comp Endocrinol 1986 Jun
PMID:ACTH-related material in the pituitary gland of the chinook salmon (Oncorhynchus tschawytscha). 302 59

A radioimmunoassay (RIA) capable of determining blood ACTH levels in salmonid fishes was developed and validated. The RIA used an antibody raised against mammalian ACTH, iodinated human ACTH as tracer, and human 1-39 ACTH as standard. Incubation of the standard or unknown with antibody for 3 days before addition of as little high-specific activity tracer as practicable (1500 cpm; equivalent to 5 pg ACTH) produced a very sensitive RIA; the operating range was 5 to 200 pg ACTH/ml. Extracts of both pars distalis and neurointermediate lobe of the pituitary glands from a range of salmonid species diluted parallel to the ACTH standard in the RIA. There was always considerably more ACTH-immunoreactivity (ACTH-IR) in the pars distalis extracts than in the neurointermediate lobe. Generally plasmas also diluted parallel to the ACTH standard, with the exception only of the plasma from sexually mature female salmonids, which diluted very non-parallel to the standard, leading to unrealistically low estimates of the ACTH-IR level. The use of heparin as an anticoagulant during collection of samples caused problems when these plasmas were immunoassayed; instead EDTA was found to be a suitable anticoagulant. When the ACTH-IR was extracted from a pool of plasma obtained from acutely stressed salmon and chromatographed on a column of BioGel P6, followed by subsequent ACTH RIA of the fractions, only a single sharp peak of ACTH-IR was detected, which eluted in the position of authentic 1-39 ACTH. The plasma ACTH-IR level in unstressed fish was low, and near the detection limit of the RIA. An acute stress, produced by crowding and confinement for 30 min, increased ACTH-IR approximately 10-fold, and plasma cortisol levels 50-fold, but the plasma alpha-MSH level was not affected. Dexamethasone-treated fish did not respond to this stressor with any increase in either ACTH or cortisol levels.
Gen Comp Endocrinol 1986 Jun
PMID:The development and validation of a radioimmunoassay to measure plasma ACTH levels in salmonid fishes. 302 60

Handling and confinement caused a steady increase in the plasma ACTH level in both coho salmon and rainbow trout. Within 2 min plasma ACTH levels had increased significantly, and by 30 min they were 5- to 8-fold higher than the basal ACTH level in unstressed fish. This type of stress also caused a pronounced elevation in plasma cortisol, which lagged behind the ACTH increase, although the degree of change was greater, the level rising between 20- and 50-fold. The plasma alpha-MSH level was unaffected by handling and confinement stress. A second series of experiments assessed the effects of a more severe stress, which consisted of 5 min out of water, during which the fish were restrained, followed by 25-min confinement in a small volume of water. This caused a very rapid, pronounced increase in the plasma ACTH level of sterile rainbow trout, the level reaching a peak at 5 min, and remaining elevated for the next 25 min. Plasma cortisol levels, which were low at the beginning of the experiment, remained so for the first 5 min, and rose thereafter. This type of stress also caused a rapid and pronounced elevation of the plasma alpha-MSH level. It rose in a very similar way, and at the same time, as the plasma ACTH level, but instead of remaining elevated it fell during the 25 min of confinement which followed the 5 min of restraint, to finish one-third of the peak value reached after 5 min.
Gen Comp Endocrinol 1986 Jun
PMID:The effects of stress on plasma ACTH, alpha-MSH, and cortisol levels in salmonid fishes. 302 61

Using the unlabelled antibody method at the light microscope level, and the immunogold method at the electron microscope level, the distribution of the different adenohypophysial cells was demonstrated in the teleost Poecilia latipinna, by means of antisera to both teleostean and mammalian pituitary hormones and their subunits. Anti-salmon prolactin, but not anti-rat or -ovine prolactin, gave a specific staining of the acidophils of the rostral pars distalis (RPD), while anti-trout growth hormone (GH), but not anti-rat GH, stained similar but always separate cells in the proximal pars distalis (PPD). Antisera to the whole molecules of mammalian glycoprotein hormones stained the entire population of basophils in the PPD, but separate populations of gonadotrophs and thyrotrophs could be discriminated using anti-salmon gonadotrophin and anti-human thyrotrophin beta subunit. Antisera to ACTH (1-24) and (11-24) sequences, as well as beta-endorphin and met-enkephalin, stained the lead haematoxylin-positive cells of the RPD and pars intermedia (PI), whereas anti-alpha-MSH stained only the PI cells. Ultrastructural examination showed that these immunoreactivities were present in the same secretory granules, and were always greater in pale granules rather than electron dense granules. In the RPD, blebs of ACTH-immunoreactive cytoplasm were found to protrude through the gaps in the basement membrane into the neurohypophysis. The second "PAS-positive" cell type of the PI showed a strong cross-reaction with anti-salmon gonadotrophin, suggesting that it may produce a glycoprotein chemically related to the gonadotrophin(s).
Gen Comp Endocrinol 1986 Jul
PMID:Immunocytochemical demonstration of pituitary cell types in the teleost Poecilia latipinna, by light and electron microscopy. 302 62

This paper reports the effects of salmonid melanin-concentrating hormone (MCH), administered via an Alzet minipump, on pigmentation and secretion of pituitary melanotrophin (MSH) and corticotrophin (ACTH) by black-adapted, adult rainbow trout. The drug induced melanin concentration in the skin melanophores and prevented melanogenesis. Both the cytological appearance of the pituitary pars intermedia and determinations of plasma alpha-MSH suggest that MCH prevented the increase in secretory activity of the melanotrophic cells seen normally in black-adapted trout. Resting plasma cortisol titres were similar in all groups of fish but anterior pituitary glands taken from stressed, MCH-treated fish released less ACTH in vitro than those from corresponding saline-treated fish.
Gen Comp Endocrinol 1986 Jul
PMID:Effects of chronic administration of melanin-concentrating hormone on corticotrophin, melanotrophin, and pigmentation in the trout. 302 63

Concentrations of immunoreactive (IR) growth hormone (GH) in the plasma of domestic fowl have been measured by homologous and heterologous radioimmunoassays and the estimates compared. Both assays detected an age-related decline in the circulating IR-GH concentration, an increase in IR-GH secretion following TRH-stimulation or fasting, and a fall in the IR-GH concentration following adrenocorticotropin administration. However, while the overall estimates of IR-GH concentration were significantly correlated, the magnitude of the changes in IR-GH concentration determined by the homologous assay were far greater than those detected by the heterologous system, which failed to show any inhibitory effect of anesthesia or exogenous thyroid hormones on basal or stimulated IR-GH release. These results suggest that the heterologous GH radioimmunoassay lacks the sensitivity of the homologous chicken GH assay and that circulating GH in birds is probably composed of heterogeneous moieties with differing immunoreactivities with rat GH antibodies.
Gen Comp Endocrinol 1987 Jan
PMID:Plasma immunoreactive-growth hormone in domestic fowl: measurement by homologous and heterologous radioimmunoassays. 302 86


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