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)

Steroid-induced difference spectra have been used to examine the combination of cholesterol with adrenal mitochondrial cytochrome P-450 which participates in cholesterol side chain cleavage (P-450scc) and the depletion of cholesterol from the cytochrome which results from turnover of the enzyme system. Type I difference spectra-induced by cholest-5-ene-3beta, 25-diol (25-hydroxycholesterol) and cholest-5-ene-3beta, 20 alpha, 22R-triol (20alpha, 22R dihydroxycholesterol) have been used to quantitate binding of cholesterol to two sites (I and II) on cytochrome P-450scc. The action of adrenocorticotropic hormone (ACTH) in vivo and the action of calcium or phosphate ions on isolated mitochondria stimulate the combination of cholesterol with site I but not site II. Cholesterol derived from lecithin-cholesterol micelles, however, binds to both sites. Malate-induced cholesterol depletion occurred at a comparable rate to the transfer of cholesterol from lecithin-cholesterol micelles. However, a residual proportion of cholesterol-cytochrome P-450scc complexes remained, even after 10 min of exposure to malate, and was of similar magnitude in mitochondria from both cycloheximide-treated and stressed rats. It is suggested that this reflects a less reactive form of cholesterol-cytochrome complex. Steroid-induced difference spectra indicate that sites I and II on cytochrome P-450scc are similarly depleted after metabolism of mitochondrial cholesterol in vitro and after inhibition of the action of ACTH in vivo. Anaerobiosis of adrenal cells after excision of the accumulation of cholesterol at cytochrome P-450cc. When anaerobiosis was prevented, cytochrome P-450scc in the freshly isolated mitochondria was apparently essentially free of complexed cholesterol, irrespective of the extent of ACTH action. For 30 min after suspension of the mitochondria in 0.25 M sucrose at 4 degrees, cholesterol combines with cytochrome P-450scc. The extent of this process was not affected by the presence of cycloheximide during ether stress treatment of the rats. It is concluded that there are at least two pools of mitochondrial cholesterol with access to cytochrome P-450scc but that ACTH stimulates only the pool which most readily interacts with the cytochrome.
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PMID:Cytochrome P-450 of adrenal mitochondria. In vitro and in vivo changes in spin states. 16 1

This study compares the efficacy of intravenous adrenocorticotropic hormone (ACTH) with intravenous hydrocortisone in the treatment of patients with symptomatic inflammatory bowel disease. Drug doses were pharmacologically equivalent on the basis of achieved plasma cortisol levels and continuously monitored urinary corticoid excretion rates. Drug selection and patient evaluation were accomplished with a random double blind technique. Evaluation of 22 consecutive hospital patients indicates that ACTH and hydrocortisone, when administered intravenously in pharmacologically equivalent dosage, are therapeutically equivalent, that response to ACTH is rapid, with no therapeutic lag, and that differences in therapeutic responses cannont be corrrelated with differences in systemic steroid levels.
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PMID:A controlled evaluation of intravenous adrenocorticotropic hormone and hydrocortisone in the treatment of acute colitis. 16 21

Denaturing solvents have been used to determine the molecular weight of the adrenocorticotropic hormone (ACTH) activity in mouse pituitary, in an ACTH secreting mouse pituitary tumor cell line (AtT-20/D-16v), and in the tissue culture medium from the pituitary tumor cells. ACTH activity was quantitated by radioimmunoassay and by bioassay. It is possible to utilize guanidine hydrochloride or sodium dodecyl sulfate in characterizing the multiple forms of ACTH because treatment of porcine ACTH (the 39 amino acid polypeptide form of ACTH, alpha(1-39)), pituitary extracts, tumor cell extracts, and tumor cell tissue culture medium with these denaturants does not diminish the immunological ACTH activity. Based on gel filtration in the presence of guanidine hydrocholoride, extracts of the pituitary tumor cells and the mouse pituitary contain three distinct molecular weight classes of ACTH activity. The major form of ACTH has a molecular weight similar to alpha(1-39) (molecular weight 4000-5500), but there are significant amounts of two higher molecular weight forms of ACTH: molecular weight 6500-9000 and molecular weight 20,000-30,000. The 6500-9000 molecular weight form of ACTH is the major form of ACTH in the tissue culture medium; there is no peak of alpha(1-39) size ACTH in the medium. In the radioimmunoasay all three forms of ACTH generate competitive binding curves parallel to that of porcine alpha(1-39); in the bioassay (stimulation of steroidogenesis in a mouse adrenal tumor cell line) the dose response curve for each of the molecular forms of ACTH is parallel to that for porcine alpha(1-39).
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PMID:High molecular weight forms of adrenocorticotropic hormone in the mouse pituitary and in a mouse pituitary tumor cell line. 16 85

The molecular weight of the adrenocorticotropic hormone (ACTH) activity in extracts of the separated anterior and intermediate-posterior lobes of the mouse pituitary was determined by gel filtration in guanidine-HCl. Following dilution or removal of the guanidine-HCl, ACTH activity was quantitated by both radioimmunoassay and bioassay. Extracts of the intermediate-posterior lobe contain approximately a tenth as much ACTH activity as extracts of the anterior lobe. In extracts of both the anterior and the intermediate-posterior lobes, about half of the immunological ACTH activity is similar in size to porcine ACTH (molecular weight 4000--5500). Two higher molecular weight forms of ACTH account for the remainder of the ACTH activity. About 40% of the immunological ACTH activity in anterior lobe extracts has a molecular weight of 6500--9000. Extracts of both the anterior lobe and the intermediate-posterior lobe contain ACTH activity with a molecular weight of 20,000--30,000. While this 20,000--30,000 molecular weight ACTH accounts for only 5% of the immunological ACTH activity in the anterior lobe extracts, it accounts for half of the immunological ACTH activity in extracts of the intermediate-posterior lobe. Extracts of an ACTH-secreting mouse pituitary tumor cell line (AtT-20/D-16v) contain the same three molecular weight forms of ACTH. Each of the three molecular weight forms of ACTH has a characteristic ratio of biological ACTH activity to immunological ACTH activity, independent of the source of the material (anterior lobe, intermediate-posterior lobe, or mouse pituitary tumor cell line).
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PMID:Molecular weights of adrenocorticotropic hormone in extracts of anterior and intermediate-posterior lobes of mouse pituitary. 17 67

Simultaneous measurements of both beta-melanocyte stimulating hormone (beta-MSH) and adrenocorticotropic hormone (ACTH) in extracted plasma were performed by specific radioimmunoassays. During insulin-induced hypoglycemia, there was a marked increase of plasma ACTH levels and a slight but significant increase of plasma beta-MSH levels. Lysine-vasopressin on the other hand, caused a significant rise of plasma ACTH levels without corresponding response of plasma beta-MSH. Following glucagon administration, neither hormone rose significantly. However, metyrapone infusion caused a significant increase of both ACTH and beta-MSH levels, and frequent blood sampling revealed that both hormones were secreted episodically, and that peaks generally coincided with each other. These data suggest that the secretion of these two hormones can occur together in most instances, and that the same mechanism is involved in the secretion of both hormones under the negative feedback control.
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PMID:Plasma levels of beta-MSH and ACTH during acute stresses and metyrapone administration in man. 17 35

The process used for extracting adrenocorticotropic hormone (ACTH) from plasma in the Searle ACTH immunoassay kit involves a loss of 70-100% of the biological activity of the ACTH.
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PMID:Loss of ACTH biological activity in plasma during extraction with a commercial radioimmunoassay kit. 17 83

A daily variation in the concentration of plasma corticosteroid hormone is present in hypophysectomized rats implanted with pellets of adrenocorticotropic hormone (ACTH) and thyroxine. Although ACTH is necessary to maintain a functional adrenal, and thyroxine is required to permit the expression of the plasma corticosteroid rhythm, a normal daily variation in plasma corticosteroid concentration does not appear to depend on the periodic release of pituitary hormones.
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PMID:Daily variation in concentration of plasma corticosteroid in hypophysectomized rats. 17 96

A double antibody immunoprecipitation technique using affinity-purified adrenocorticotropic hormone (ACTH) antiserum was employed to investigate the biosynthesis of ACTH in a mouse pituitary tumor cell line. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of cell extracts resolved four forms of ACTH with apparent molecular weights of 4,500, 13,000, 23,000, and 31,000. These four forms of ACTH can be detected by radioimmunoassay of cell extracts or by immunoprecipitation of cell extracts following incubation of cultures in [3H] tryptophan, [3H] lysine, or [3H] tyrosine. The double antibody immunoprecipitation scheme developed is specific, quantitative, and reproducible. ACTH biosynthesis was examined in both steady and pulse-labeling experiments using [8H] tyrosine or [3H] lysine. The results of these experiments are consistent with the proposal that Mr=31,000 ACTH is the biosynthetic precursor for all three smaller forms of ACTH and that Mr=23,000 ACTH is a biosynthetic intermediate. Both Mr=13,000 ACTH and Mr=4,500 ACTH are derived from the intracellular processing of Mr=31,000 ACTH.
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PMID:Biosynthesis of adrenocorticotropic hormone in mouse pituitary tumor cells. 18 15

An attempt to define in quantitative terms the characteristics of the biphasic rate curve for pregnenolone synthesis in cell-free systems from the adrenal using male Sprague-Dawley rats is reported. When adrenocorticotropic hormone (ACTH) was used 2 units of .2 ml of .9% saline were injected ip 15 minutes before killing the rats. The effect of ACTH on adrenal steroidogenesis is in the stimulation of the rate of conversion of cholesterol to pregnenolone. This reaction sequence is thought to occur in the mitochondria. Methods of preparing subcellular fractions are described. Incubation of pregnenolone with mitochondria for 20 minutes at 20 degree C resulted in a 70% disappearance of the pregnenolone. This loss does not occur if the mitochondria are boiled, indicating an enzymatic process. The rate of pregnenolone synthesis characteristically shows a biphasic curve with a rapid primary rate and a slower secondary rate. ACTH administration in vivo increased both rates but the percentage increase was greater for the secondary rate. In addition an increase in the duration of the primary rate resulted. Different explanations are offered for these characteristics. Pregnenolone may act as an inhibitor of its own synthesis from cholesterol but not from 20alpha-hydroxycholesterol. Substances that cause mitochondria to swell may stimulate pregnenolone synthesis. Another theory proposes that the limiting ACTH-sensitive step is the rate at which mitochondrial cholesterol is transported to or binds to the cholesterol side-chain cleavage enzyme. The possible role of an inhibitor in the regulation of steroidogenesis is indicated. Data are consistent with the observation that the transition from the primary rate to the slower secondary rate shows the accumulation of an inhibitory substance. The action of ACTH would then be to modify the structure of the cholesterol side-chain cleavage enzyme so that there is a decreased susceptibility of the enzyme to the inhibitor.
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PMID:Some characteristics of adrenal steroidogenesis and their possible relationships to the action of the adrenocorticotropic hormone. 18 Aug 93

The role of growth hormone (GH), prolactin (PRL), and adrenocorticotropic hormone (ACTH) in the induction of the PRL receptor was investigated in hypophysectomized male rat livers and in the livers of male rats bearing a GH secreting tumor. After 7 days of sc injections, specific binding of PRL in controls and rats treated with PRL, GH, ACTH, human chorionic gonadotropin, estradiol, or testosterone was approximately 1%. Treatment with PRL plus ACTH increased specific binding to 4%; adding estradiol to this combination produced a further increase to 8%, whereas the addition of testosterone decreased hepatic binding to 1%. Combination of GH with ACTH was most effective giving a specific binding of 33%, which is similar to the 36% observed in the liver of rats bearing a GH-secreting tumor. These results suggest that GH acts synergistically with PRL and/or ACTH to increase lactogenic binding sites in the male rat liver and that sex steroids have a modulating effect on this action.
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PMID:Induction of lactogenic receptors. II. Studies on the liver of hypophysectomized male rats and on rats bearing a growth hormone secreting tumor. 18 48


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