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)

Somatostatin and dihydrosomatostatin (H2somatostatin) are equipotent in inhibiting insulin and glucagon release induced by arginine in the rat. The ID50 of H2somatostatin on insulin and glucagon secretion induced by arginine are 14 +/- 6 and 6 +/- 10 mug/100 g BW respectively, similar to the ID50 of H2somatostatin (18 +/- 10 mug/100 g BW) on inhibition of insulin release induced by glucose. Thyrotropin releasing factor, luteinizing hormone releasing factor, alpha-MSH, and the N-terminus decapeptide of the beta-chain of porcine hemoglobin did not alter the secretion of insulin and glucagon induced by arginine. With the exception of [Ala2[-somatostatin and [Ala5]-somatostatin, alanine substituted analogs of somatostatin were less potent than somatostatin. [D-Trp8]-somatostatin is 6-8 times as potent as somatostatin in inhibiting insulin and glucagon release induced by arginine. The relative potencies of these analogs to inhibit the secretion of the pancreatic hormones are in good agreement with our previously reported values based on the inhibition of GH secretion in vitro.
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PMID:Biological activity of somatostatin and somatostatin analogs on inhibtion of arginine-induced insulin and glucagon release in the rat. 81 91

The effects of alpha-MSH and several other vasoactive substances on the mesenteric vascular bed were studied in the anesthetized cat under conditions of controlled blood flow. Intra-arterial injections of alpha-MSH in doses of 10, 30, and 100 mug resulted in significant dose-related decreases in mesenteric arterial perfusion pressure but little or no effect on systemic arterial pressure. The vasodilator response to alpha-MSH was breif in duration and resistance to flow was decreased 10, 18, and 26 percent at 10, 30, and 100 mug. These significant changes after alpha-MSH were of a much smaller magnitude than were observed after prostaglandins E1 and E2, isoproterenol, bradykinin or glyceryl trinitrate and differed completely from the increased resistance after angiotensin II and norepinephrine.
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PMID:Comparison of alpha-MSH and several vasoactive substances on vascular resistance in the feline mesenteric vascular bed. 82 86

The alpha-MSH levels in the frog hypophysis were measured by use of a sensitive ans specific radioimmunoassay. Sephadex G-50 gel chromatography of frog pars distalis and pars intermedia extracts showed that frog hypophyseal MSH was chemically related to synthetic alpha-MSH. Rat tissue homogenates were capable of degrading frog pars intermedia MSH as well as synthetic alpha-MSH. These results provide evidence that the frog hypophysis--pars intermedia and pars distalis--contains an alpha-MSH-like peptide.
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PMID:[Melanotropic hormone in the green frog (Rana esculenta): biochemical and radioimmunological study]. 82 75

Application of the 2-methylsulfonylethyloxycarbonyl group for temporary amino protection enables the synthesis from one precursor of des-Nalpha1-acetyl-alpha-MSH, the two mono N-acetylated forms (in positions I and II) and the diacetyl form of this tridecapeptide amideq The free tridecapeptide amide, although structurally unrelated to the normal substrate, was recognized by an enzyme occurring in calf eye-lens tissue. The product of the enzymatic reaction was exclusively alpha-MSH. Partial sequences derived from the N-terminus were less rapidly acetylated or not at all, depending on their chain length. The enzyme, therefore, appears to direct its activity to free N-terminal alpha-amino groups of peptides exceeding a certain critical chain length. Acetylation of epsilon-amino functions did not occur.
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PMID:Des-Nalpha-acetyl-alpha-melanotropin: a synthetic substrate for specific N-terminal directed enzymatic acetylation. 83 31

Two analogues of alpha-MSH are described, in which the tryptophan residue occuring in position 9 of the natural hormone has been replaced by pentamethylphenylalanine and phenylalanine, respectively. The analogues were synthesized via a conventional procedure and the [Phe9]-analogue also by a semi-synthetic approach, which demonstrated the favourable properties of the applied, new amino-protecting Msc function for this purpose. The widely different electron donor properties of the substituted residues were accompanied by a large difference in melanocyte stimulating activity of the analogues. The [Pmp9]-analogue, having donor properties comparable to those of the natural compound, was four to five times more active than the analogue containing the poorly donating Phe residue. The opposite effect was noted in in vivo lipolysis in rabbits.
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PMID:Investigation of the role of tryptophan in alpha-MSH. Replacement by L-pentamethylphenylalanine and L-phenylalanine. 84 38

The present experiment investigated the opposite effects of synthetic alpha-MSH and Melatonin on acquisition and extinction of a passive avoidance response (PAR) and on emotionality, as indexed by defecation, in the PA box. It was found that intraperitoneal (IP) administration of alpha-MSH delayed extinction and increased defecation responses whereas IP administration of Melatonin facilitated extinction of the PAR and decreased defecation. The present experiment confirmed MSH-Melatonin opposition on memory and on the defecation response.
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PMID:Effects of melanocyte-stimulating hormone (MSH) and melatonin on passive avoidance and on an emotional response. 88 81

The neurointermediate lobes of dark-adapted toads Xenopus laevis were incubated for 30 min in [3H]arginine and then "chased" for various time periods. By use of this pulse-chase paradigm there were detected 10 trichloroacetic acid (TCA)-precipitable peptides separated on acid-urea polyacrylamide gels and one TCA-soluble peptide separated by high-voltage electrophoresis (pH 4.9) with melanotropic activity. Each of these peptides had a different degree of melanocyte stimulating hormone (MSH) activity as revealed by the Anolis skin bioassay. Three of these TCA-precipitable peptides comigrated with ACTH, beta-lipotrophin, and alpha-MSH on acid-urea gels. Evidence suggesting a precursor-product mode of biosynthesis of the melanotropic peptides is presented. 7 of the 10 TCA-precipitable peptides and the one TCA-soluble peptide with melanotropic activity were released into the medium. The half-time of release of the TCA-precipitable peptides was about 2 h, whereas the half-time of TCA-soluble peptide release was about 30 min. The release of these peptides was inhibited by 5 X 10(-5) M dopamine. Dopamine inhibition of release did not appear to affect the biosynthesis of the melanotropic peptides, but did appear to enhance the degradation of the newly synthesized TCA-soluble peptide in the tissue. White adaptation of the toads greatly decreased the biosynthesis of all of the TCA-precipitable melanotropic peptides.
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PMID:Biosynthesis, processing, and control of release of melanotropic peptides in the neurointermediate lobe of Xenopus laevis. 89 50

The effect of the chronic administration of alpha-MSH on the incorporation of tritiated tyrosine into noradrenalin and dopamine and of tritiated tryptophan into serotonin was studied in different regions of the rat brain. Alpha-MSH increased the incorporation of tritiated trytophan into serotonin in the cortex and slightly decreased that of tryosine into the dopamine in the hypothalamus. As the brain concentration of serotonin was unchanged in the animals treated with alpha-MSH, it is suggested that some of the changes in behavior, which other investigators have found following the administration of peptides containing the same sequence of amino acids to that found in MSH, could be associated with an increased turnover of cortical serotonin.
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PMID:The effect of alpha-melanocyte stimulating hormone (alpha-msh) on the metabolism of biogenic amines in the rat brain. 93 8

In healthy women (21-28 years) the influence of synthetic alpha-MSH upon the peripheral plasms levels of LH, FSH, progesterone and cortisol was determined during the corpus luteum phase of the menstrual cycle. As controls 3 women were given 6 intravenous infusions of 250 ml NaCl; 4 women received a total of 18 intravenous infusions of 5-20 mg alpha-MSH from 9.00 to 11.00 a.m. on the 5th and 7th hyperthermic day of the menstrual cycle. The blood levels of the hormones were usually followed for 24 h, and in two cases for 48 h. During and after the control as well as the experimental infusions with 5-20 mg alpha-MSH, no significant changes in the plasma concentrations of LH, FSH and progesterone were found. The cortisol concentrations, however, showed on the average a 2-fold increase over the initial values during the infusion of 5 mg and 10 mg alpha-MSH. During the control infusions they were not enhanced. One experiment was conducted with 20 mg alpha-MSH. The increase in the plasma cortisol levels following alpha-MSH administration generally seemed to be dose dependent, but statistically no significant differences regarding the increase in cortisol level could be detected between the 5 mg and 10 mg doses.
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PMID:Effect of alpha-MSH on plasma levels of LH, FSH, progesterone and cortisol during the corpus luteum phase of the menstrual cycle. 94 46

Radioactive synthetic alpha-MSH, prepared by selective tritiation of its dibromo-L-tyrosine-derivative, was injected into the carotid artery of intact, hypophysectomized or pinealectomized rats. More radioactivity was found in the occipital cortex, cerebellum, and pons-medulla than in most other brain parts of rats decapitated 15 sec and, to a less significant extent, 30 min after injection. Part of this radioactivity behaved like alpha-MSH in several identification procedures. After administration of 3H-tyrosine, the least radioactivity was consistently found in the pons-medulla. Large amounts of radioactivity after 3H-alpha-MSH were found in the pituitary and, particularly in the hypophysectomized rats, in the pineal. The half-time disappearance of the first component of radioactivity from the blood of each group of rats injected with tritiated-alpha-MSH was no more than 2.5 minutes, a time considerably shorter than the behavioral and EEG effects of this pituitary hormone on visual attention.
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PMID:Distribution of 3H-alpha-MSH in rat brain. 97 94


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