Topic
Hydroxysteroid dehydrogenase
About: Hydroxysteroid dehydrogenase is a research topic. Over the lifetime, 1087 publications have been published within this topic receiving 28468 citations. The topic is also known as: hydroxysteroid dehydrogenase.
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TL;DR: The 7-hydroxycoumarins, umbelliferone and 4-methylumbellifer one (IC 50 =1.4 and 1.9 μM, respectively) were potent inhibitors of human testes microsomal 17 β -HSD (type 3) enzyme whereas 7-methoxycou marin, 4-HydroxycOUmarin and 7-ethoxyCoumarin had little or no inhibitory activity.
Abstract: The 7-hydroxycoumarins, umbelliferone and 4-methylumbelliferone (IC 50 =1.4 and 1.9 μM, respectively) were potent inhibitors of human testes microsomal 17 β -HSD (type 3) enzyme whereas 7-methoxycoumarin, 4-hydroxycoumarin and 7-ethoxycoumarin had little or no inhibitory activity. Analogues of the weak inhibitory triphenylethenes tamoxifen and clomiphene but lacking the basic substituent, were weak inhibitors of the human microsomal enzyme. Inhibitory activity was improved by replacement of the triphenylethene structure with a triphenylmethyl (17, 52.6% inhibition) or phenylpropyl (16, 94.8%, IC 50 =42.1 μM) skeleton. Further studies on tamoxifen using rat testes microsomal 17 β -HSD showed that the inhibition was time-dependent and irreversible but not specifically mechanism-based.
23 citations
TL;DR: In a series of cinnamates and related coumarin-3-carboxylates, a number of compounds proved to be potent inhibitors of both the oxidative and reductive reactions catalyzed by 17beta-HSDcl, with IC(50) values in the low micromolar range.
23 citations
TL;DR: 20α-Hydroxysteroid dehydrogenase activity, believed to be present exclusively in regressing corpora lutea, was demonstrated in preovulatory follicles of immature rats exposed 52 h previously to pregnant mare serum gonadotropin.
23 citations
TL;DR: Steroid substrates did not protect 20β-hydroxysteroid dehydrogenase against acid inactivation or affect enzyme fluorescence and it was concluded that under the experimental conditions little steroid was bound to the enzyme in the the absence of coenzyme.
23 citations
TL;DR: Differences in the relative levels of the various metabolites were observed for the two age groups and in the different types of cells and unfractionated cells from immature and mature rat prostates.
Abstract: To study androgen-mediated differentiation in the rat ventral prostate, we separated the two principal cell types (epithelial and stromal) derived from prostates of immature and mature rats on two continuous Percoll gradients. Cells were immediately placed in culture medium. Testosterone metabolism by the two prostatic cell types was evaluated using [3H]testosterone and quantifying the formation of 5 alpha-[3H]dihydrotestosterone (5 alpha-DHT) and 5 alpha-[3H]androstane-(3 alpha or 3 beta), 17 beta-diols. In epithelial cells from both immature and mature rat prostates the major testosterone metabolites were 5 alpha-DHT and 5 alpha-androstane-3 alpha, 17 beta-diol. Stromal cells metabolized less testosterone than did the epithelial cells. Differences in the relative levels of the various metabolites were observed for the two age groups. To examine in more detail the changes in testosterone metabolism observed in vitro both types of cells and unfractionated cells from immature and mature rat prostates were assayed for testosterone 5 alpha-reductase (using testosterone as substrate) and 3 alpha-hydroxysteroid dehydrogenase (using 5 alpha-DHT as substrate) activities (expressed as pmol substrate reduced/min per 10(6) cells). In immature rats both 5 alpha-reductase and 3 alpha-hydroxysteroid dehydrogenase activities were localized in the epithelial cell fraction (17 and 52 respectively); stromal cells showed lower 5 alpha-reductase and 3 alpha-hydroxysteroid dehydrogenase activity (4 and 4). Relative to epithelial cells from immature rats epithelial cells from mature rats showed a decrease in 5 alpha-reductase (7) and an increase in 3 alpha-hydroxysteroid dehydrogenase (160) activity while stromal 5 alpha-reductase showed little change (3) and 3 alpha-hydroxysteroid dehydrogenase increased to 22.(ABSTRACT TRUNCATED AT 250 WORDS)
23 citations