Showing papers on "Hydroxysteroid dehydrogenase published in 1976"
TL;DR: It is suggested that during sexual maturation the testicular biosynthesis of active 5-ane androgens may proceed via5-ane precursors with the help of age-dependent 5-anes-3beta-hydroxysteroid dehydrogenase activities.
Abstract: The activities of hydroxysteroid dehydrogenases of 5-ane and 5-ene steroids were examined in interstitial tissue from testes of rats at different ages. The enzyme reactions were localized in the Leydig cell cytoplasm of isolated cells and in frozen tissue slices. Relative reaction velocities of the NADlinked hydroxysteroid dehydrogenases were obtained spectrophotometrically with 17 steroid substrates using the 12,000 i g supernatant of isolated interstitial cells from 28–29 clay old rats; the rate of 3(α,β) dehydrogenation of 5-ane-3β steroids was markedly (10 to 20i) higher than that of 5-ene-3β steroids and 5-ane-3α steroids. The hydroxysteroid dehydrogenase activities of testes from 124 rats between the ages of 15 and 138 days were determined using as substrates, 3β-hydroxy- 5β-androstan-17-one, 3β-hydroxy-5a-androstan- 17-one, 3β,17β-dihydroxy-5α-androstane, dehydroepiandrosterone and pregnenolone. Between the ages of 15 and 32 or 34 days the gonads grow in size more rapidly than the body and the 5-an...
144 citations
TL;DR: The 3α- and 12α-hydroxysteroid dehydrogenase activities, although differing in cofactor requirements cannot be distinguished by their appearance in the growth curve, their mobility on disc gel electrophoresis, elution volume on passage through Sephadex G-200 or heat inactivation studies, appear to be constitutive rather than inducible.
69 citations
TL;DR: It is concluded that HSD is present in the inner mitochondrial membrane and, therefore, that the enzyme has a dual mitochondrial and microsomal localization in the rat adrenal cortex.
Abstract: SummaryIn this study we have compared some properties of the microsomal and mitochondrial 3β-hydroxysteroid dehydrogenase/isomerase (HSD) from the rat adrenal cortex. The following major differences were noted: (i) the microsomal enzyme required exogenous NAD while the mitochondrial enzyme was active in the absence of added NAD. (ii) The mitochondrial enzyme was inhibited by a combination of rotenone, KCN, and citric acid cycle substrates. These agents did not influence the activity of the microsomal enzyme, (iii) The ratio of the specific activities of HSD to the 21-hydroxylase (a microsomal marker enzyme) was greater in the mitochondria than in the microsomes. We conclude that HSD is present in the inner mitochondrial membrane and, therefore, that the enzyme has a dual mitochondrial and microsomal localization in the rat adrenal cortex.The authors wish to thank Drs. P. J. Mulrow and S. Y. Tan for several helpful discussions during the course of this study.
17 citations
TL;DR: The microsomal 3-hydroxysteroid dehydrogenases were solubilized with lubrol, a non-ionic detergent and purified by double affinity chromatography on 5alpha-dihydrotestosterone-Sepharose to show that this enzyme can use both NADH and NADPH as coenzymes.
Abstract: The microsomal 3-hydroxysteroid dehydrogenases were solubilized with lubrol, a non-ionic detergent. A 3alpha-hydroxysteroid dehydrogenase is purified about 100-fold by double affinity chromatography on 5alpha-dihydrotestosterone-Sepharose. This enzyme can use both NADH and NADPH as coenzymes.
16 citations
TL;DR: Results indicated that the 3β and 17β-hydroxysteroid dehydrogenase was involved in steroid uptake by membrane vesicles ofP.
11 citations
TL;DR: The isolation of an equatorial 3-hydroxysteroid dehydrogenase from liver microsomes of male rats is reported, which converts both 5aand 5/3dihydrotestosterone (DHT) to the corresponding 3a-Hydroxysteroids
9 citations
TL;DR: It is demonstrated that the testicular 20a-hydroxysteroid dehydrogenase is not assembled into a polymeric form even while performing its enzymic function.
7 citations
TL;DR: The mouse epididymis was studied to localize histochemically a number of hydroxysteroid dehydrogenases in the various zones, and the epithelium of the posterior half of the initial segment (head) and the anteriorhalf of the middle segment (body) shows a strong reaction for delta5-3beta-, 3alpha,5alpha, 3 alpha,5beta, 11beta, 16alpha, 17beta, 20alpha-hydroxysteroid dehydration.
Abstract: The mouse epididymis was studied to localize histochemically a number of hydroxysteroid dehydrogenases in the various zones. The epithelium of the posterior half of the initial segment (head) and the anterior half of the middle segment (body) shows a strong reaction for △5-3β-, 3α,5α-, 3α,5β-, 11β-, 16α-, 170β- 20α- and 20β-hydroxysteroid dehydrogenases. This activity attenuates posteriorly. Only the 11β-hydroxysteroid dehydrogenase is present throughout the length of the epididymis. The luminal contents of the middle segment also show the histochemical utilization of a number of steroids.
6 citations
TL;DR: Observations provide an exception to the rule proposed by Alworth and Bentley that with regard to the paired methylene hydrogens at C-4 of NADH and NADPH "the stereospecificity of a particular reaction is fixed and does not vary with the source of the enzyme preparation".
Abstract: In the reduction of 17beta-hydroxy-5alpha-androstan-3-one to the 3beta-alcohol, horse liver alcohol dehydrogenase utilizes the 4-pro-R hydrogen of NADH whereas the 3(17)beta-hydroxysteroid dehydrogenase of Pseudomonas testosteroni utulized the 4-pro-S hydrogen. These observations provide an exception to the rule proposed by Alworth and Bentley that with regard to the paired methylene hydrogens at C-4 of NADH and NADPH "the stereospecificity of a particular reaction is fixed and does not vary with the source of the enzyme preparation". It is also apparent that for these two enzymes, the selection of the side of NADH from which hydride is transferred to substrate cannot in both cases be dictated by the "best fit" of substrate and cofactor.
5 citations
TL;DR: In vivo, 20beta-hydroxysteroid dehydrogenase appears to consist of four equal subunits, and the monomers, molecular weight of 27 300, show a high tendency to form dimers and tetramers in the absence of dissociating agents.
Abstract: Antiserum against crystallized 20beta-hydroxysteroid dehydrogenase from Streptomyces hydrogenans was used for various immunodiffusion and immunoprecipitation tests to show an increase of the de novo synthesis of 20beta-hydroxysteroid dehydrogenase by Streptomyces hydrogenans after cultivation of the cells in the presence of 11beta,21-dihydroxy-4,17(20)-pregnadien-3-one. Half lives of mRNA for 20beta-hydroxysteroid dehydrogenase in induced cells and of total mRNA in non-induced cells were calculated to be 126 s and 66 s, respectively. In vivo, 20beta-hydroxysteroid dehydrogenase appears to consist of four equal subunits. The monomers, molecular weight of 27 300, show a high tendency to form dimers and tetramers in the absence of dissociating agents. The aggregation is completely reversible in the presence of increasing concentrations of sodium dodecylsulfate.
4 citations
Journal Article•
TL;DR: Adult male albino rats showed characteristic stimulating effect on adrenocortical tissues with marked depletion of ascorbic acid, cholesterol containing neutral lipids and significant increase in the delta5-3 beta -hydroxysteroid dehydrogenase and glucose-6-phosphate dehydration activities in the zona fasciculata and zona reticularis regions.
Abstract: Acute intraperitoneal administration of delta-9-THC (at doses of 10 mg/kg and 50 mg/kg) to adult male albino rats showed characteristic stimulating effect on adrenocortical tissues with marked depletion of ascorbic acid, cholesterol containing neutral lipids and significant increase in the delta5-3 beta -hydroxysteroid dehydrogenase and glucose-6-phosphate dehydrogenase activities in the zona fasciculata and zona reticularis regions. Adrenal weights and the histometric measurements of the adrenocortical areas showed no significant changes. Chronic intraperitoneal administration of delta-9-THC (at doses of 10 mg/kg per day for 15 days) produced marked accumulation of cholesterol containing neutral lipids, with increase in ascorbic acid and delta5-3 beta-hydroxysteroid dehydrogenase and glucose 6-phosphate dehydrogenase activities in the fasciculata-reticularis regions. Adrenal weights and histometric measurements revealed marked hypertrophy of the adrenal glands.
TL;DR: In this paper, the localization of Δ 5 -3 β -hydroxysteroid dehydrogenase activity was demonstrated histochemically in the neonatal mouse ovary, and the effects of gonadotropic deprivation from birth to age 7 or 14 days on the distribution of enzymatic activity was investigated.
TL;DR: Antiserum against crystallized 20β-hydroxysteroid dehydrogenase from Streptomyces hydrogenans was used for different immunodiffusion and immunoprecipitation tests to quantify the bacterial enzyme in cell-free supernatants of the microorganism.
Abstract: Antiserum against crystallized 20beta-hydroxysteroid dehydrogenase from Streptomyces hydrogenans was used for different immunodiffusion and immunoprecipitation tests to quantify the bacterial enzyme in cell-free supernatants of the microorganism. After immunoprecipitation and gel electrophoresis the molecular weight of the subunits of 20beta-hydroxysteroid dehydrogenase was calculated to be 27 300 +/- 700.
01 Jan 1976
TL;DR: In this paper, the 17β-hydroxysteroid dehydrogenase of rat testes was not completely solubilized by several available procedures, such as treatments with detergents, phospholipases, organic solvents, sonication, freezing and thawing, etc.
Abstract: Testicular 17β-hydroxysteroid dehydrogenase was localized intracellularly in the agranular microsomal fraction among the organelles of the interstital tissue. The microsomal 17β-hydroxysteroid dehydrogenase of rat testes was not completely solubilized by several available procedures, such as treatments with detergents, phospholipases, organic solvents, sonication, freezing and thawing, etc. Recently, however, the 17β-hydroxysteroid dehydrogenase of porcine testes, which was also present in the microsomal fraction was solubilized by sonication, and partially by freezing and thawing. The solubilized dehydrogenase of the porcine testes was purified by a fractional ammonium sulfate precipitation, and column chromatographies through Sephadex G-100, DEAE-cellulose, and Bio-Gel P-100, and finally, an apparent homogeneous preparation was obtained. Using the enzyme preparation obtained at the last step of purification, its molecular weight and radius, optimal temperature and pH, cofactor requirement, substrate preference, stoichiometry, stereochemical relationship between the substrate and NADPH through the oxido-reduction, and its activity as transhydrogenase from NADPH to NAD+ were examined.