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 effects of temperature on adenylate cyclase (AC) activity from rat white adipocytes were studied. Arrhenius plots of the data were found to be biphasic for basal AC activity, with a break near 27 degrees C. Noradrenaline and corticotropin induced a shift in the break with a rise in energy of activation (Ea) on both sides of the break. Aabove break point only, Ea increased with respect to hormone does as a hyperbolic function. The maximum value was in the range 17-21 Kcal x mol-1. Temperature was shown to have only a slight effect on the binding capacity of corticotropin to its receptor sites. The possibility of the existence of multiple thermodynamic states for the enzyme is envisaged. Basal AC activity is thermodynamically different from the hormone-stimulated enzyme. Hormones induce changes in the basal conformation of the enzyme, and this is reflected in modifications of Arrhenius plots. The maximal state of activation reached with high doses of hormones could be interpreted as a 'desensitization' of enzyme and/or enzyme systems to membrane lipid interactions.
Mol Cell Endocrinol 1977 Jun
PMID:Temperature dependence of adenylate cyclase activity from rat white adipocytes. 1 77

Antisera to ACTH were produced in rabbits injected repeatedly at multiple intradermal sites with synthetic [Asp25, Ala26, Gly27]alphah-corticotropin-(1-28)-octacosapeptide-bovine gamma globulin conjugate (octacosapeptide is a sequence analogue of alphah1-28-ACTH). Antibodies to extracted human or porcine ACTH were detected in all of the sera 1 month after immunization. A considerable proportion of the antisera obtained from a single final bleeding 5 months after the primary immunization were suitable for sensitive radioimmunoassay. The antisera were shown to neutralize the steroidogenic activity of ACTH in an isolated rat adrenal cell bioassay system. Titres estimated from antiserum dilution curves and relative avidities from the standard curves were compared. It was possible to detect picogram amounts of ACTH in plasma-free medium with the best antisera. The method described is an effective means of producing anti-sera to the weakly immunogenic N-terminal fragment of the ACTH molecule.
Mol Cell Endocrinol 1977 Sep
PMID:Preparation and assessment of antisera to ACTH. 7 98

Substance P stimulation of salivation in rats has been studied as has its in vitro enhancement of amylase release by isolated parotid cells. The extent of the stimulation on amylase release by isolated parotid cells was dependent upon the concentration of substance P, with the minimum effective concentration being 1 nM. The substance P effect was detectable within 1 min after incubation and lasted for at least 50 min. Substance P stimulation was demonstrable at 25--37 degrees C but not at 0 degrees C. Adrenocorticotropic hormone (ACTH), thyrotropin-releasing hormone (TRH), vasopressin and neurotensin had no effect on amylase release. These results suggest that substance P may act directly on the parotid cells. Examination of the salivary-stimulating activity of fragments of substance P showed that the C-terminal octapeptide and (pyroglutamyl)hexapeptide were active, although less potent than substance P, whereas its free acid, C-terminal tetra- and tri-peptides were inactive. Vasopressin, angiotensin II and neurotensin could inhibit substance P induced salivation, whereas TRH, ACTH and somatostatin had no effect. Amylase activity per unit volume of saliva was not changed by the injection of vasopressin, angiotensin II or neurotensin. These vasoactive peptides did not affect substance P stimulation of amylase release by isolated parotid cells. The results indicate that vasopressin, angiotensin II and neurotensin inhibit the action of substance P on salivation at sites other than the parotid cells.
Mol Cell Endocrinol 1979 Sep
PMID:Substance P stimulation of amylase release by isolated parotid cells and inhibition of substance P induction of salivation by vasoactive peptides. 22 41

Specific radioimmunoassays (RIAs) for ACTH, beta-endorphin, alpha-MSH and beta-MSH were used to identify the immunoreactive components released during incubation of rat anterior pituitary cells in primary culture. Such measurements were performed after separation of the incubation media by chromatography on Sephadex G-50 or G-75. The ACTH-RIA measured approximately equal amounts of 13 and 4.5K ACTH while equal proportions of components migrating at the position of beta-LPH and beta-endorphin were measured in the beta-endorphin RIA system. Immunoreactive components migrating at the position of gamma-LPH and alpha-MSH were measured in the beta-MSH and alpha-MSH RIA systems, resp. 3 purified corticotropin-releasing fractions (CRF) prepared from porcine hypothalami and increasing concentrations of N6,O2'-dibutyryl cyclic AMP and theophylline led to parallel release of ACTH, beta-endorphin, beta-MSH and alpha-MSH immunoreactivities while preincubation with dexamethasone led to a 30-60% inhibition of the release of all peptides. The present data show that the release of ACTH, beta-LPH, beta-endorphin, gamma-LPH and alpha-MSH-like immunoeactivities occurs in parallel in anterior pituitary cells in culture both under basal and acute stimulatory or inhibitory conditions of release.
Mol Cell Endocrinol 1979 Nov
PMID:Parallel release of ACTH, beta-endorphin, alpha-MSH and beta-MSH-like immunoreactivities in rat anterior pituitary cells in culture. 22 47

We have previously shown that cultured bovine pituitary or hypothalamic cells incorporate 3H-labeled amino acids into high molecular weight glycoproteins containing the antigenic determinants of both corticotropin (ACTH) and beta-endorphin. We now report resolution of this 3H-labeled ACTH/beta-endorphin-like material into two predominant size classes upon SDS polyacrylamide-gel electrophoresis with apparent molecular weights (Mr) of 41 500 +/- 1600 and 36 000 +/- 1100. Isoelectric focusing revealed these components to be basic proteins with apparent isoelectric points greater than 8.5. Overnight trypsinization generated a 3H-labeled fragment comigrating with synthetic beta-lipotropin (61-69) [beta-endorphin (1-9)] upon paper electrophoresis which was immunoprecipitable with antibody directed against the corresponding synthetic fragment. Limited trypsinization of bovine immunoreactive ACTH/beta-endorphin extracted from freshly obtained bovine hypothalamic and anterior pituitary tissue, generated fragments which possessed ACTH bioreactivity. Both bovine pituitary and hypothalamic derived material are similar with respect to these foregoing physiochemical parameters and appear to be larger than the reported forms in mouse pituitary.
Mol Cell Endocrinol 1979 Dec
PMID:Preliminary characterization of in vitro synthesized hypothalamic precursor ACTH/beta-endorphin-like material. 23 Jan 5

Protein biosynthesis in neurointermediate lobes of mouse pituitaries was investigated using pulse and pulse-chase techniques with [3H]lysine. Electrophoretic analysis of lobe homogenates on acid-urea gels resolved 11 labeled products. One was a large protein which was rapidly synthesized during pulse-incubations and disappeared during chase incubations. Three of the products increased during chase incubations, suggesting a precursor-product mode of biosynthesis for these chasde peptides. One of these three products co-migrated with synthetic alpha-MSH and also corresponds to the major peak of mouse neurointermediate lobe MSH bioactivity and immunoactivity on electrophoretograms. Another case of these peptides has electrophoretic properties similar to those of ACTH.
Mol Cell Endocrinol 1979 Feb
PMID:Biosynthesis of MSH and related peptides in the pars intermedia of the mouse: a pulse-chase analysis. 44 80

alpha-Adrenergic receptors are present on the plasma membrane of normal anterior pituitary cells and alpha-adrenergic agonists may play a role in the secretion of corticotropin (ACTH) and thyrotropin (TSH). However, alpha-adrenergic involvement in prolactin (PRL) secretion is uncertain. We have therefore examined this question in the PRL-secreting clonal rat pituitary tumor-derived GH4C1 cells. Norepinephrine (NE), an alpha-adrenergic agonist, had no effect on basal PRL secretion but abolished thyrotropin-releasing hormone (TRH)-induced PRL secretion in a dose-dependent manner (EC50 100 nM). NE also significantly suppressed the TRH-stimulated rise in [Ca2+]i. Phentolamine (PA), a non-selective alpha-adrenergic antagonist, reversed the inhibitory effect of NE on both the TRH-stimulated PRL secretion and [Ca2+]i rise. NE did not inhibit the rise in PRL secretion or [Ca2+]i induced by depolarizing 30 mM K+, 30% hyposmolarity or BAY K-8644, a specific L-type Ca2+ channel agonist. The inhibitory effect of NE on TRH-induced PRL and [Ca2+]i changes was also present when Ca2+ influx was prevented by removing medium Ca2+ or by blocking L-type Ca2+ channels with 2 microM nifedipine. The TRH-stimulated first-phase rise in [Ca2+]i in GH4C1 cells is believed to result primarily from release of sequestered Ca2+ from an intracellular pool through the activation of inositol 1,4,5-trisphosphate (IP3) and this [Ca2+]i spike stimulates PRL secretion. Our data thus suggest that GH4C1 cells have alpha-adrenergic receptors and that alpha-adrenergic agonists either suppress IP3 generation or block IP3 release of sequestered intracellular Ca2+.
Mol Cell Endocrinol 1992 Sep
PMID:Alpha-adrenergic inhibition of thyrotropin-releasing hormone-induced prolactin secretion in GH4C1 cells is associated with a depressed rise in intracellular Ca2+. 128 Feb 33

We have investigated the pharmacological profile of the opioid stimulation of adenylate cyclase activity in rat olfactory bulb, in order to identify the opioid receptor subtype(s) involved in this response. The synthetic delta-selective agonists (D-Ala2)deltorphin I, (2-D-penicillamine,5-D-penicillamine)-enkephalin, and (D-Ser-Leu5-enkephalyl)-threonine were effective stimulators of the enzyme activity, with EC50 values of 6.7, 420, and 63 nM, respectively. A significant increase was also observed with the mu-selective agonists (N-methyl-Phe3,D-Pro4)-morphiceptin, dermorphin, and (D-Ala2-N-methyl-Phe4-Gly-ol5)-enkephalin (DAGO). The latter two agonists displayed biphasic concentration-response curves, with high affinity components accounting for 75-80% of the maximal responses. The kappa-selective agonists U-50,488 and U-69,593 were ineffective, whereas (D-Ala2)dynorphin A-1-11, dynorphin A, dynorphin A-1-13, and dynorphin A-1-6 acted with a rank order of potency consistent with their affinity for delta receptors. The stimulatory responses of Leu-enkephalin, beta-endorphin, dynorphin A, and delta-selective agonists were counteracted by naltrindole with pA2 values of 9.39-8.93, whereas naloxone was less potent (pA2 = 8.17-7.59). The kappa-selective antagonist norbinaltorphimine was the least potent. The inhibition by naltrindole and naloxone of DAGO stimulation showed biphasic curves, with 90% of the response being antagonized more potently by naloxone than by naltrindole. These results demonstrate that delta- and mu- but not kappa-opioid receptor subtypes stimulate basal adenylate cyclase activity in rat olfactory bulb.
Mol Pharmacol 1992 Jul
PMID:Characterization of opioid receptors mediating stimulation of adenylate cyclase activity in rat olfactory bulb. 132 51

Regulation of corticotropin-releasing hormone (CRH) gene expression in vivo was assessed via in situ hybridization histochemistry, using probes directed against an intronic sequence of the CRH gene. Initial characterization of the CRH intron (CRHin) probe revealed specific localization of signal to the nuclear compartment of neurons in the medial parvocellular paraventricular hypothalamus, which are known to produce CRH peptide and mRNA. Abundance of CRHin signal was low, commensurate with a low resting pool of CRH heteronuclear RNA (hnRNA), representing CRH primary transcript. Regulation of CRH hnRNA levels was assessed after acute glucocorticoid synthesis blockade by injection of metyrapone. Metyrapone inhibits the conversion of 11-deoxycorticosterone to corticosterone, thereby rapidly depleting glucocorticoids and serving as a discrete stimulus for hypothalamo-pituitary-adreno-cortical activation. Plasma hormone measurements verified the efficacy of treatment, as metyrapone-treated rats showed extremely low basal corticosterone levels at all postinjection time points, while exhibiting progressive increases in plasma ACTH release over the 60-min postinjection period. CRH hnRNA levels were markedly increased 15-30 min after metyrapone injection, consistent with a rapid induction of CRH gene transcription in response to the stimulatory event. CRH mRNA, on the other hand, did not exceed control levels until 60 min post metyrapone, illustrative of a temporal lag between transcriptional changes and detectable changes in mRNA pools. Additional sections from metyrapone-and vehicle-treated rats were hybridized with probes complementary to mRNA encoding the immediate-early gene c-fos. c-fos was not present under unstimulated conditions yet was rapidly induced upon metyrapone treatment or vehicle injection (15 min).(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Endocrinol 1992 Jul
PMID:Rapid regulation of corticotropin-releasing hormone gene transcription in vivo. 132 19

The intracellular mechanisms of action of alpha-MSH in rat adrenocortical cells were examined. When rat adrenal capsule (largely glomerulosa) cells were stimulated with a range of concentrations of alpha-MSH there was significant stimulation of aldosterone secretion at 10(-10) mol/l, although cyclic AMP was not increased until high concentrations of alpha-MSH were used (10(-6) mol/l and above). However, cells incubated with ACTH showed an increase in aldosterone secretion at 10(-11) mol/l and levels of cyclic AMP were elevated at 10(-9) mol ACTH/l. When rat adrenal whole capsules were incubated with alpha-MSH, membrane-bound protein kinase C (PKC) activity was increased and cytosolic enzyme activity decreased, showing PKC activation. Stimulation with angiotensin II also induced translocation of PKC activity, but ACTH did not. When [3H]inositol-loaded glomerulosa cells were stimulated with alpha-MSH there was significant generation of [3H]inositol trisphosphate (IP3) at concentrations of alpha-MSH which stimulated secretion of aldosterone. Significantly increased levels of [3H]IP3 were also measured when loaded cells were exposed to angiotensin II. ACTH did not cause any significant stimulation of [3H]IP3 production at any concentration used. These results indicate that activation of PKC and phospholipase C is important in modulating the steroidogenic effect of alpha-MSH.
J Mol Endocrinol 1992 Aug
PMID:Studies on the intracellular mechanism of action of alpha-melanocyte-stimulating hormone on rat adrenal zona glomerulosa. 132 51


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