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)

Rat adrenal cortical cells have been prepared by collagenase dissociation of trypsin-treated adrenal tissue. The content and compositions of cholesteryl ester, phospholipid, and triglyceride fatty acids compare favorably with those of undissociated rat adrenal tissue. During 2-hour control incubations of adrenal cortical cells, steroidogenesis was not detected, and the levels of sterol ester, phospholipid, and triglyceride fatty acids were not significantly altered. Incubations with adrenocorticotropic hormone (ACTH) resulted in coricosterone production and significant depletions of sterol ester and triglyceride fatty acids, but not of phospholipid fatty acids. Although all fatty acid esters of cholesterol were hydrolyzed under these conditions, the greatest contributions to the net decrease in sterol esters were by oleate, arachidonate, and adrenate. Incubations with dibutyryl cyclic adenosine monophosphate (0.5 mM) resulted in significantly greater levels of corticosterone production than did ACTH (250 muunits), but the effects on cellular lipids were comparable to those seen with the tropic hormone. This study represents the first demonstration of hormone-induced hydrolysis of sterol esters in an in vitro cell suspension system. The results are discussed with respect to hormone-sensitive sterol ester hydrolase of adrenal cortex, and to the role of endogenous cholesteryl esters in the steroidogenic pathway.
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PMID:ACTH-induced hydrolysis of cholesteryl esters in rat adrenal cells. 20 12

Melanophores from tadpoles of Xenopus laevis (Daudin) were isolated by digestion of tail fins with acetyltrypsin and collagenase and maintained in primary culture for 6 weeks up to 3 months. Within 36 to 72 h the melanophores develop one to eight dendritic processes per cell; secondary and tertiary branchings of the processes were frequently observed. The melanophores in primary culture disperse under the influence of alpha-MSH or cyclic AMP; upon rinsing out these substances the cells aggregate. In darkness, about 40% of the cells disperse their pigment, whereas under illumination the pigment of the melanophores aggregates. To date, attempts to initiate cell division in melanophores have not been successful.
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PMID:Morphological and physiological aspects of melanophores in primary culture from tadpoles of Xenopus laevis. 22 62

The role of cyclic AMP in the regulation of aldosterone production by adrenocorticotropic hormone (ACTH), angiotensin II (A II), potassium, and serotonin was examined in collagenase-dispersed adrenal glomerulosa cells. The ability of 8-bromo cyclic AMP and choleragen to stimulate maximum aldosterone production indicated that cyclic AMP could act as second messenger for certain of the aldosterone-stimulating factors. The actions of ACTH and choleragen on aldosterone and cyclic AMP production were correlated in dog and rat cells, and a similar relation was seen during stimulation of rat cells by serotonin. In contrast, A II and potassium did not cause changes in cyclic AMP formation while stimulating aldosterone production. Intracellular and receptor-bound cyclic AMP were increased 3-fold by 10(-7) M ACTH but not by A II. Addition of a phosphodiesterase inhibitor increased the magnitude of the cyclic AMP response to ACTH but did not change the lack of stimulation by A II or potassium. In dog cells, the effects of A II and potassium on aldosterone production were partially additive to those of ACTH, choleragen, and 8-bromo cyclic AMP. In contrast, no additivity was observed between A II and potassium, or between combinations of the cyclic AMP-dependent stimuli. These results indicate that the actions of ACTH on aldosterone secretion are mediated by cyclic AMP formation, whereas A II and potassium stimulate aldosterone production through an independent mechanism. The lack of additivity between steroid responses to A II and potassium suggests that these factors could share a common mode of action on steroidogenesis in zona glomerulosa cells.
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PMID:The role of cyclic AMP in aldosterone production by isolated zona glomerulosa cells. 22 59

Oestrous rats and golden hamsters were anesthetized with pentobarbital, one of the femoral arteries and veins and one of the ovarian veins were cannulated. Blood fractions were collected from the ovary. After the first two fractions synthetic adrenocorticotropic hormone (ACTH) or human chorionic gonadotropin (hCG) was injected i.v. Blood pressures and ovarian blood flow were continuously recorded. Progesterone (P) and oestradiol-17 beta (E2) were determined from the ovarian venous blood by radioimmunoassay (RIA). ACTH induced a temporary elevation in the ovarian blood flow, P and E2 secretion both in rats and hamsters. In rats and hamsters hCG induced a continuous elevation in P secretion but the ovarian blood flow and E2 secretion remained unchanged. Luteal cells from pseudopregnant rats or oestrous hamsters were dispersed with collagenase and incubated with ACTH or hCG. A sample of the cells was preincubated with polymixin-B, indomethacin or ibuprofen. P and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) contents of the medium and cyclic 3,5 adenosine monophosphate (cAMP) content of the cells were determined by RIA. ACTH stimulated the release of 6-keto-PGF1 alpha and the secretion of P from the luteal cells of both species, which was inhibited by indomethacin or ibuprofen, but ACTH did not alter the cAMP content of luteal cells. The polymixin-B prevented ACTH to stimulate P secretion, but it did not elevate the 6-keto-PGF1 alpha release, while the cAMP content of the cells remained unchanged. It is supposed that the polyphosphoinositol-Ca(2+)-protein kinase-C second messenger system is involved in the ACTH induced stimulation of P secretion.
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PMID:Action of ACTH in the luteal ovary. 166 58

Pro-opiomelanocortin (POMC) gene expression and POMC peptides have been demonstrated in the Leydig cells of the testis, although selective removal of the Leydig cells with the cytotoxic drug ethane dimethane sulfonate did not significantly reduce levels of testicular POMC mRNA or peptides in adult rats. Since macrophages in the rat spleen synthesize POMC peptides, we investigated whether isolated macrophages from the adult rat testis may be an additional source of POMC-derived peptides. Testicular macrophages were isolated by collagenase treatment of adult rat testes and adherence to siliconized glass coverslips; the biological, cytochemical and immunological characteristics of the attached cells were compared with those of Leydig cells purified by Percoll gradient centrifugation. Macrophages in the cell preparations were identified by positive esterase cytochemical staining, latex bead ingestion, and immunocytochemical staining with ED2 (a macrophage-specific monoclonal antibody), and an absence of 3 beta-hydroxysteroid dehydrogenase cytochemical staining. Leydig cells in the purified preparations were positive for 3 beta-hydroxysteroid dehydrogenase and esterase staining but negative with ED2, and were not phagocytic. Based on these criteria, the purities of the macrophage and Leydig cell preparations employed in this study were estimated to be 87 +/- 4% and 91 +/- 3%, respectively. Cytoplasmic beta-endorphin (beta EP) immunoreactivity (ir) was present in 62 +/- 9% of cells in the purified Leydig cell preparations--confirming these cells as a source of POMC-derived peptides. In addition, ir-beta EP and ir-ACTH were localized to the cytoplasm of a similar proportion of cells (beta EP, 62.5 +/- 5%; ACTH, 64 +/- 5%) in macrophage preparations.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Localization of immunoreactive beta-endorphin and adrenocorticotropic hormone and pro-opiomelanocortin mRNA to rat testicular interstitial tissue macrophages. 166 44

Myotubes prepared from the Japanese quail embryo at 9 days gestation were cultivated in the presence of glycyl-L-glutamine (Gly-Gln, beta-endorphin C-terminal dipeptide) or glycyl-glutamic acid (Gly-Glu), and changes in the activity of acetylcholinesterase (AChE) molecular forms and binding of 125I-alpha-bungarotoxin (alpha BGT) to cell surface nicotinic acetylcholine receptors were measured. The A12 oligomer was the major form of AChE in the cultures. The activity of all molecular forms of the enzyme was increased in the presence of Gly-Gln, but Gly-Glu did not alter AChE activity. In cells infected with the temperature-sensitive mutant, La31C, of Rous sarcoma virus (ts-RSV) and transferred to the nonpermissive temperature, the A12 form of AChE was absent, but its activity could be induced following exposure of the cells to Gly-Gln. When cells treated in this way were incubated in the presence of collagenase, there was a small but significant loss of A12 AChE activity, indicating that Gly-Gln stimulated the activity of a pool of this oligomer which was mainly but not entirely intracellular. Neither Gly-Gln nor Gly-Glu influenced 125I-alpha BGT binding after exposure of the cells to the peptides for any duration. Neither Gly-Gln nor Gly-Glu influenced the accumulation of cyclic AMP in the cultures. beta-Endorphin is one of a family of peptides that coexist transiently with acetylcholine in lower motoneurones of vertebrates in the perinatal period. This report provides evidence for the selective trophic activity of one of its derivatives toward the postsynaptic cholinergic system in avian muscle cells.
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PMID:Glycyl-L-glutamine stimulates the accumulation of A12 acetylcholinesterase but not of nicotinic acetylcholine receptors in quail embryonic myotubes by a cyclic AMP-independent mechanism. 215 12

To determine if opioid peptides have a local effect on the modulation of progesterone (P4) synthesis, a study was made of the effect of beta-endorphin and leu-enkephalin on P4 production by pure preparations of small luteal cells and dissociated luteal cells comprising both small and large cells from cows 2-3 months pregnant. Corpora lutea were dispersed by collagenase, and the large and small luteal cells were separated using Percoll gradients. Viable luteal cells (5 x 10(5)) were incubated in 0.5 mL of Eagle medium for 2 h at 37 degrees C, in an atmosphere of 5% CO2. Cells were treated with 8-bromoadenosine 3',5'-monophosphate (8Br-cAMP), hCG, beta-endorphin (BE) and leu-enkephalin (LE) alone or in combination. When small luteal cells were used, P4 synthesis was significantly enhanced in the presence of opioid peptides alone (P less than 0.01); there was an additive effect with 8Br-cAMP and with hCG. For dissociated luteal cells, opioid peptides alone had no effect on P4 production but the stimulation of P4 production induced by 8Br-cAMP or hCG was significantly (P less than 0.01) inhibited in the presence of opioid peptides. In contrast, dissociated luteal cells that were preincubated with PGF2 alpha (degranulation) responded to the presence of BE with increased P4 synthesis similar to that seen with the pure preparation of small luteal cells. It is concluded that opioid peptides play an auto/paracrine role in both basal and tropic hormone-induced stimulation of steroidogenesis by the bovine luteal cell.
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PMID:Effect of beta-endorphin on steroidogenesis by bovine luteal cells. 221 91

Recombinant plasmids coding for fusion proteins which consist of human adrenocorticotropin joined to N-terminal sequences of Escherichia coli alkaline phosphatase via collagenase-sensitive linkers were constructed and used for the production of these proteins by transformed E. coli cells. It was shown that repetitive linkers of the form -Gly-(Pro-Xaa-Gly)n-Pro- with n greater than or equal to 2 were cleaved by clostridiopeptidase A (Clostridium histolyticum) by orders of magnitude faster than corresponding nonrepetitive sequences (n = 1). The C-terminal cleavage product was Gly-Pro-adrenocorticotropin which could be converted to the authentic hormone by dipeptidyl peptidase IV. On the basis of these enzymatic reactions a procedure for the preparation of pure adrenocorticotropin was developed. Derivatives of alkaline phosphatase containing similar repetitive linker sequences were cleaved by clostridiopeptidase A as efficiently as the adrenocorticotropin fusion proteins.
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PMID:Production of human adrenocorticotropin by cleavage of alkaline-phosphatase-derived fusion proteins containing repetitive recognition sequences for collagenases. 257 29

The effect of cortisol or adrenocorticotropic hormone (ACTH) on basal and gonadotropin-releasing hormone (GnRH)-induced secretion of luteinizing hormone (LH) was studied in vitro using dispersed pig pituitary cells. Pig pituitary cells were dispersed with collagenase and DNAase and then grown in McCoy's 5a medium containing 10% dextran charcoal-pretreated horse serum and 2.5% fetal calf serum for 3 days. Cells were preincubated with cortisol or ACTH before GnRH was added. When pituitary cells were incubated with 400 micrograms cortisol/ml medium for 6 h or longer, increase basal secretion of LH was observed. However, GnRH-induced LH release was reduced by cortisol. The degree of this reduction was dependent on cortisol, and a concentration of cortisol higher than 100 micrograms/ml was needed. Cortisol also inhibited the 17 beta-estradiol-induced increase in GnRH response. ACTH-(1-24), ACTH-(1-39), or porcine ACTH had no influence on GnRH-induced LH secretion. Our results show that cortisol can act directly on pig pituitary to inhibit both normal and estradiol-sensitized LH responsiveness to GnRH.
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PMID:Effect of cortisol or adrenocorticotropic hormone on luteinizing hormone secretion by pig pituitary cells in vitro. 282 56

The secretion of aldosterone and its responses to stimulation have been studied in rat adrenal zona glomerulosa tissue incubated as intact capsules or as collagenase-dispersed cell suspensions, and in intact perfused rat adrenal glands. Several differences are apparent in the functions of the various preparations. Aldosterone secretion rates are similar in incubated intact capsules and in the perfused gland. Relative to corticosterone, lower yields of aldosterone are obtained in dispersed glomerulosa cell in vitro. This may be related to the loss in the dispersed cells of a pool of tissue steroid (aldosterone or a precursor) which is revealed only in intact tissue incubations by trypsin stimulation of aldosterone secretion. Trypsin-released aldosterone is increased by prior dietary sodium restriction. In addition, differences occur in the responses of dispersed cells and perfused glands to stimulation. Perfused glands from animals on a normal diet are less sensitive to stimulation by ACTH or alpha-MSH, but more sensitive than dispersed cells to angiotensin II amide. In the perfused gland, sensitivity of response (lowest effective concentration) to all three stimulants is increased by prior dietary sodium restriction, in contrast to dispersed cells in which increased sensitivity has been reported only to alpha-MSH. The perfused gland is particularly sensitive to angiotensin II amide, and a bolus administration of 1 amol gives significant stimulation in glands from animals on low sodium intake. Electrical (field) stimulation or dopamine administration at 10(-6) mol/l (which is ineffective in dispersed cells) both depress aldosterone secretion by the perfused gland. The data suggest that the sequestered pool of steroid is utilized in the perfused gland for aldosterone secretion. They furthermore suggest that in the intact gland there are mechanisms, which involve neural components, for intraglandular regulation of aldosterone secretion, which are lost in dispersed cells in vitro. Such mechanisms may be involved in sensitivity increases in sodium depletion.
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PMID:Control of aldosterone secretion in zona glomerulosa cell suspensions and in the perfused adrenal gland of the rat. 282 12


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