Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q7LGC8 (HSD)
 3,196 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A study of the ultrastructural localization of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD), glucose-6-phosphate dehydrogenase (G-6-PD), beta-hydroxybutyrate dehydrogenase (beta-HBD), NADH diaphorase (NADH-D) and NADPH diaphorase (NADPH-D) in the guinea-pig testis is reported. The procedures employed included short immersion or perfusion fixation with aldehydes followed by incubation of small blocks in a tetrazolium salt or a ferricyanide medium. The effects of incubation conditions were investigated, and a reaction medium for the ultracytochemical demonstration of 11 beta-HSD is described. Using suitable controls, evidence for the specificity of the cytochemical reactions is presented. It was found that all the enzymes studied were present in both the Leydig and Sertoli cells of the guinea-pig testis and that the intracellular distribution pattern for each enzyme was independent of the cell type. Using tetrazolium salt techniques, both 3 beta-HSD and 11 beta-HSD activities were localized on or in membranes of smooth endoplasmic reticulum and within the mitochondria. With the ferricyanide techniques, G-6-PD activity was found to be associated mainly with the smooth endoplasmic reticulum membranes, while beta-HBD activity was limited to mitochondria. With both the tetrazolium salt and ferricyanide techniques, the reaction products for NADH-D and NADPH-D activities showed localizations which were similar to those observed for the steroid dehydrogenases.
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PMID:The ultrastructural localization of the enzymes related to steroid hormone metabolism in the guinea-pig testis. 42 99

By recording the incubation time needed for initial appearance of the red and blue formazans the reliability of the histochemical method for 3beta-HSD was investigated: 1. Prefixation of small tissue blocks with 1% W/V methanol-free formaldehyde (pH=7.2) for up to 30 min preserved morphological integrity as well as maximal enzyme activity. Moreover, the substantivity of formazans and lipids was enhanced. 2. Commercial available glutaraldehyde (pH=7.2) induced SH groups in the tissue (even at 0.1% W/V for 5 min) thereby enhancing the Nothing dehydrogenase reaction. 3. Preextraction of lipids with acetone for 20 min at -30 degree C caused no loss of activity and was an inevitable step if a reliable activity pattern had to be achieved (e.g. in interstitial cells). 4. No diffusion of enzyme was noticed within 30 min of preincubation in phosphate buffer (0.2 M, pH=7.2) at 20 degree C. 5. By using the double-section incubation method no diffusion of 3beta-HSD or rediffusion of NADH or PMSH could be noticed withn 45 min of incubation, provided that low concentrations of NAD (0.1 mg/ml) and PMS (0.003 mg/ml) were balanced against the concentration of Nitro BT (0.5 mg/ml) or Tetranitro BT (1.0mg/ml). 6. The utlity of different inhibitors of alkaline phosphomonoesterase was tested and discussed. 7. By inhibiting alkaline phosphomonoesterase with 0.1 mM of L-p-bromotetramisole or 16 mM of beta-glycerophosphate, 3beta-HSD was shown to be exclusively NAD-linked. 8. Levamisole was a potent inhibitor of NADH-tetrazolium reductase as well as 3 beta-HSD, but not of NADPH-tetrazolium reductase. 9. 3beta-HSD possess SH groups requisite for the activity as this enzyme was totally inhibited by N-ethyl maleimide. 10. Whether alcohol dehydrogenases may use steroids as substrate is discussed; It is concluded that preextraction (by acetone) and/or the use of an inhibitor of alcohol dehydrogenase (1,10-phenanthroline) has to be performed. 11. Propylene glycol was a poor solvent for all substrates and was itself an excellent substrate for alcohol dehydrogenase. 12. Specifications for the ideal solvent of steroid substrates in the histochemical practice are proposed. DMSO showed to be promising as a steroid solvent (e.g. extraction of formazans was considerably lower as compared to DMF). 13. The utilization of substrates was descending in the following order (using 1 mM and 0.1 ml/ml of either DMF or DMSO): epiandrosterone, methandriol, dehydroepiandrosterone and pregnenolone. 14. If DMSO was used as solvent for pregnenolone (but not for the other substrates tested) an evident increase of activity was recorded as compared to DMF.
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PMID:Histochemistry of 3beta-hydroxysteroid dehydrogenase in rat ovary. I. Amethodological study. 55 64

Adult rats of both sexes were either gonadectomized or hypophysectomized and gonadectomized. Three to eight weeks later they were treated for 14 consecutive days with oil or with 75 or 200 mug testosterone propionate (TP) per 100 g body weight. The animals were killed and for each sex the gonadectomized animals were compared with the hypophysectomized-gonadectomized animals as far as their NADPH- and NADH-dependent 3alpha-hydroxy-steroid dehydrogenases (3alpha-HSD) in renal microsomes, transcortin levels in serum and five organ weights relative to total body weight were concerned. For two of the latter, i.e. the relative kidney and prostatic weights, no significant differences were found. Transcortin levels, relative adrenal weights and renal NADPH-dependent 3alpha-HSD activities were higher in oil-treated gonadectomized animals than in oil-treated hypophysectomized-gonadectomized animals. The opposite was found for the relative weights of uterus and seminal vesicles and renal NADH-dependent 3alpha-HSD activities. These differences between gonadectomized and hypophysectomized-gonadectomized animals disappeared after TP treatment as far as transcortin levels were concerned but remained for the five other parameters. After gonadectomy sexual differences subsisted for all parameters studied. But whereas intact male rats had higher NADH-dependent 3alpha-HSD activities than female rats the opposite was found after gonadectomy. After gonadectomy plus hypophysectomy the between sex differences disappeared as far as transcortin levels were concerned but remained in the other parameters studied.
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PMID:Effects of testosterone mediated or modulated by pituitary factors. 119 29

3 alpha-Hydroxysteroid dehydrogenase (3 alpha-HSD) was purified greater than 500-fold from human liver cytosol. The purification was monitored using 5 beta-[3H]dihydrocortisol (5 beta-DHF) as substrate. Electrophoretically homogeneous enzyme was obtained using a procedure that involved ammonium sulfate precipitation and three successive column chromatography steps: DEAE-cellulose, hydroxylapatite and Blue-Sepharose. The enzyme is a monomer since the native molecular weight was found to be 37,000, using a calibrated Sephadex G-75 column, and the denatured subunit molecular weight was determined to be 38,500, by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. The enzyme had a pI of 5.6-5.9. The 3-ketosteroids: cortisol, testosterone, progesterone and androstenedione, were not substrates for 3 alpha-HSD indicating that a saturated 4,5 double bond was required for substrate activity. The conformation at the 5 position, however, did not influence substrate activity since 5 alpha- and 5 beta-DHF and 5 alpha-dihydrotestosterone were all reduced at similar rates. The purified enzyme preferred NADPH to NADH as a cofactor and showed a broad peak of activity in the pH range of 6.8-7.4. The apparent Km for 5 beta-DHF was 18 microM. The enzyme was markedly stabilized by 50 mM phosphate buffer containing 10 to 20% glycerol at 4 degrees C. Freezing and thawing of the enzyme resulted in a large loss of activity during early stages of the purification. This is the first report of the purification to homogeneity of 3 alpha-HSD from human tissue.
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PMID:Purification and properties of human hepatic 3 alpha-hydroxysteroid dehydrogenase. 139 Feb 84

In earlier studies, two distinct molecules, 20 alpha-HSD-I and 20 alpha-HSD-II, responsible for 20 alpha-HSD activity of pig adrenal cytosol were purified to homogeneity and characterized [S. Nakajin et al., J. Steroid Biochem. 33 (1989) 1181-1189]. We report here that the purified 20 alpha-HSD-I, which mainly catalyzes the reduction of 17 alpha-hydroxyprogesterone to 17 alpha,20 alpha-dihydroxy-4-pregnen-3-one, catalyzes 3 alpha-hydroxysteroid oxidoreductase activity for 5 alpha (or 5 beta)-androstanes (C19), 5 alpha (or 5 beta)-pregnanes (C21) in the presence of NADPH as the preferred cofactor. The purified enzyme has a preference for the 5 alpha (or 5 beta)-androstane substrates rather than 5 alpha (or 5 beta)-pregnane substrates, and the 5 beta-isomers rather than 5 alpha-isomers, respectively. Kinetic constants in the reduction for 5 alpha-androstanedione (Km; 3.3 microM, Vmax; 69.7 nmol/min/mg) and 5 beta-androstanedione (Km; 7.7 microM, Vmax; 135.7 nmol/min/mg) were demonstrated for comparison with those for 17 alpha-hydroxyprogesterone (Km; 26.2 microM, Vmax; 1.3 nmol/min/mg) which is a substrate for 20 alpha-HSD activity. Regarding oxidation, the apparent Km and Vmax values for 3 alpha-hydroxy-5 alpha-androstan-17-one were 1.7 microM and 43.2 nmol/min/mg, and 1.2 microM and 32.1 nmol/min/mg for 3 alpha-hydroxy-5 beta-androstan-17-one, respectively. 20 alpha-HSD activity in the reduction of 17 alpha-hydroxyprogesterone catalyzed by the purified enzyme was inhibited competitively by addition of 5 alpha-DHT with a Ki value of 2.0 microM. Furthermore, 17 alpha-hydroxyprogesterone inhibited competitively 3 alpha-HSD activity with a Ki value of 150 microM.
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PMID:3 alpha-hydroxysteroid dehydrogenase activity catalyzed by purified pig adrenal 20 alpha-hydroxysteroid dehydrogenase. 154 86

3 Alpha-hydroxysteroid dehydrogenase (3 alpha-HSD) from Pseudomonas testosteroni was shown to reduce the xenobiotic carbonyl compound metyrapone (MPON). Reversely, MPON reductase purified from mouse liver microsomes and previously characterized as aldehyde reductase, was competitively inhibited by 3 alpha-HSD steroid substrates. For MPON reduction both enzymes can use either NADH or NADPH as co-substrate. Immunoblot analysis after native and SDS gel electrophoresis of 3 alpha-HSD gave a specific crossreaction with the antibodies against the microsomal mouse liver MPON reductase pointing to structural homologies between these enzymes. In conclusion, there seem to exist structural as well as functional relationships between a mammalian liver aldehyde reductase and prokaryotic 3 alpha-HSD. Moreover, based on the molecular weights and the co-substrate specificities microsomal mouse liver MPON reductase and Pseudomonas 3 alpha-HSD seem to be members of the short-chain alcohol dehydrogenase family.
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PMID:Functional and immunological relationships between metyrapone reductase from mouse liver microsomes and 3 alpha-hydroxysteroid dehydrogenase from Pseudomonas testosteroni. 155 29

3-alpha-Hydroxysteroid dehydrogenase (3 alpha-HSD) (EC 1.1.1.50) is an important multifunctional oxidoreductase capable of metabolizing steroid hormones, polycyclic aromatic hydrocarbons, and prostaglandins. 3 alpha-HSD is also required for bile acid synthesis and has been suggested to play an important role in net bile acid transport across the hepatocyte (Stolz, A., Takikawa, H., Ookhtens, M., and Kaplowitz, N. (1989) Annu. Rev. Physiol. 51, 166-177). In order to characterize molecular forms and begin to determine its regulation, we now report the nucleotide sequence, tissue distribution, and homology to other members of the oxidoreductase superfamily. Rat hepatic 3 alpha-HSD cDNA encodes for a 322-amino acid protein with a predicted molecular weight of 37,022 expressed in a 2.4-kilobase (kb) message size. Northern blot analysis of total RNA revealed equivalent steady-state levels in liver and intestine in male rats with lower levels of expression in the colon and minimal expression in stomach, lung, and testis. Female liver contained approximately 2-3-fold greater steady-state levels of mRNA as compared to the male liver with equivalent intestinal expression. Two hybridizing bands, 2.4 and 1.4 kb, were identified in total RNA from the ovary. 3 alpha-HSD exhibits 75% amino acid sequence homology with bovine lung prostaglandin F synthetase and 50% homology with human aldose reductases. Amino acid sequence analysis with short chain alcohol dehydrogenases identified a possible NADP(H) cofactor-binding site at the amino terminus. The significant homology of 3 alpha-HSD with both prostaglandin F synthetase and aldose reductases suggest a subdivision of monomeric, NADPH reductases within the larger oxidoreductases superfamily.
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PMID:Molecular structure of rat hepatic 3 alpha-hydroxysteroid dehydrogenase. A member of the oxidoreductase gene family. 171 56

17 Beta-Hydroxysteroid dehydrogenase (17 beta-HSD) is present in multiple forms in human breast tissue. One soluble form, with a molecular weight of approximately 35 kDa, was purified to near homogeneity from whole normal breast tissue. This form catalysed the oxidation of oestradiol and the reduction of oestrone, with NADP+ and NADPH as the preferred coenzymes. Three other soluble forms with higher molecular weights (in the range 50-80 kDa) were isolated. They catalysed the oxidation of oestradiol but not the reduction of oestrone, and all of them had properties very different from those of the low molecular weight enzyme. Activities of 17 beta-HSD were measured in particulate and soluble fractions from normal breast adipose and non-adipose tissues, and from breast tumours obtained from post-menopausal women, in the oxidative direction with NAD+ and NADP+ as coenzymes and in the reductive direction with NADH and NADPH as coenzymes. Particulate fractions from tumours had much higher oxidative and reductive activities than those from normal tissues. Soluble fractions from tumours had higher oxidative activities than those from the normal tissues but similar reductive activities. The major soluble form of 17 beta-HSD in adipose tissue was the 35 kDa enzyme which had both oxidative and reductive activities. In contrast, the majority of the soluble activity in non-adipose tissue was due to enzymes, with molecular weights in the range 50-80 kDa, which had oxidative activity only. The soluble fractions of tumours, like those of non-adipose tissue, contained enzymes with molecular weights in the range 50-80 kDa. In addition, they contained a 35 kDa enzyme with properties different from those of the enzyme with the same molecular weight present in adipose tissue.
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PMID:17 Beta-hydroxysteroid dehydrogenases in human breast tissues: purification and characterization of soluble enzymes and the distribution of particulate and soluble forms in adipose, non-adipose and tumour tissues. 189 41

Pig testicular 20 beta-hydroxysteroid dehydrogenase (20 beta-HSD) has also 3 alpha- and 3 beta-HSD (3 alpha/beta-HSD) activities. The purified 20 beta-HSD preparation from neonatal pig testes could catalyze the conversion of 5 alpha-dihydrotestosterone (5 alpha-DHT) in the presence of beta-NADPH to 5 alpha-androstane-3 alpha,17 beta-diol and 5 alpha-androstane-3 beta,17 beta-diol at the ratio of 4:3, and the specific 3 alpha/beta-HSD activity of 20 beta-HSD for 5 alpha-DHT was about 10 or 15 times larger than the 20 beta-HSD activities for 17 alpha-hydroxypregn-4-ene-3,20-dione (17 alpha-hydroxyprogesterone) or progesterone, respectively. The result indicates that the testicular 20 beta-HSD has high 3 alpha(axial, 3R)- and 3 beta(equatorial, 3S)-HSD activity. The testicular 20 beta-HSD could catalyze the reversible conversion of various 5 alpha- or 5 beta-dihydrosteroids which have a 3-carbonyl or 3-hydroxyl group with beta-NADP(H) as the preferred cofactor. The enzyme transferred the 4-proS hydrogen of NADPH to the 5 alpha-DHT for both 3 alpha- and 3 beta-hydroxylation and it was the same as the 20 beta-hydroxylation of 17 alpha-hydroxyprogesterone. Although the 3 alpha/beta-HSD activity has been known to be present in 3 alpha,20 beta-HSD of Streptomyces hydrogenans, the enzymological properties for 3 alpha/beta-HSD activity catalyzed by testicular 20 beta-HSD were different from the properties for 3 alpha/beta-HSD activity catalyzed by prokaryotic 3 alpha, 20 beta-HSD with respect to the specificity of the catalytic reaction and the cofactor requirement.
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PMID:20 beta-hydroxysteroid dehydrogenase of neonatal pig testis: 3 alpha/beta-hydroxysteroid dehydrogenase activities catalyzed by highly purified enzyme. 206 95

An analogue of androstenedione containing an ethano bridge between carbons 2 and 10 of the A ring of the steroid, 1, has been evaluated as an inhibitor and a possible substrate of human placental aromatase. This compound was found to be a competitive inhibitor versus androstenedione (Kis = 25 +/- 2 nM) of the aromatase activity. Analyses of the incubation mixtures of 1 with human placental microsomes and NADPH by GC-MS indicated the formation of a new compound having an increase in molecular weight of 2 mass units (300 m.u.) from that of the parent steroid (298 m.u.). Subsequent analyses of incubations of 1 with an isolated 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) from Pseudomonas testosteronii in the presence of NADPH resulted in the formation of a new compound having the same retention time and molecular mass as that found for the product from the placental microsome incubation. Consequently, steroid 1 is both an inhibitor of human placental aromatase and a substrate for 17 beta-HSD.
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PMID:Enzyme interactions of 2,10-ethanoandrostene-3,17-dione: aromatase and 17 beta-hydroxysteroid dehydrogenase. 216 Dec 28


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