Showing papers on "Hydroxysteroid dehydrogenase published in 1969"

Hydroxysteroid dehydrogenase activity in the placenta of the domestic pig.

Abstract: A histochemical method was used for the detection and localization of Δ5-3β- and 17β-hydroxysteroid dehydrogenase activity in the epitheliochorial placenta of the domestic pig, Sus scrofa. Placentas were obtained from the fourth week of gestation until term (114 days) and showed much the same substrate specificity throughout pregnancy. Both dehydroepiandrosterone and 3β,17β-dihydroxyandrost-5-ene (androstenediol) were better substrates than pregnenolone, particularly in the earlier stages. 17α- Hydroxypregnenolone was not utilized. With testosterone and estradiol-17β as substrates, the presence of both neutral and phenolic 17β-hydroxysteroid dehydrogenase enzymes could be demonstrated. No activity was seen with estradiol- 17α. The significance of these findings is discussed in relation to the possible role of the placenta in estrogen production in the sow. (Endocrinology 84: 426, 1969)

[30] Purification of ovarian 20α-hydroxysteroid dehydrogenase

Abstract: Publisher Summary This chapter describes the assay method for purification of ovarian 20α-hydroxysteroid dehydrogenase. Activity of the enzyme is determined spectrophotometrically by following the rate of increase of the absorbancy at 340 mμ associated with the reduction of triphosphopyridine nucleotide (TPN) to TPNH in the presence of excess 20α-hydroxypregn-4-en-3-one-4- 14 C. This partial purification of 20α-hydroxysteroid dehydrogenase results in the elimination of reactivity toward diphosphopyridine nucleotide (DPN + ) and 17α-hydroxyprogesterone. The enzyme preparation shows absolute specificity for the 20α-hydroxyl group of certain steroids and for TPN + . It does not react with the 20β-hydroxyl, 17α-hydroxyl, 17-ketone, or 21-hydroxyl groups of steroids or with the nonsteroids, secondary butyl alcohol, and ethanol.

Differentiation of the mammary gland in experimental congenital adrenal hyperplasia due to inhibition of delta 5,3beta-hydroxysteroid dehydrogenase in rats.

Abstract: Summary The development of mammary glands has been studied in fetuses of pregnant rats treated with an analog (2α-cyano-4, 4,17α-trimethyl-androst-5-en-17β3-ol-3-one) of a C-19 substrate of 3β-hydroxysteroid dehydrogenase and Δ5-4, 3-ketosteroid isomerase, which is a selective inhibitor of these enzymes. In male fetuses, the analog causes the development of nipples, which are normally suppressed by fetal testicular function. In light of the previous demonstration of the feminizing effect of the analog on the male external genitalia due to inhibition of the fetal testicular dehydrogenase, this observation suggests that inactivation of the testicular dehydrogenase system leads to insufficient endogenous Δ4,3-ketoandrogen (testosterone) production, thus allowing the development of the nipple in the male. In female fetuses, the analog inhibits nipple development, probably because of adrenal overproduction of 3β-hydroxyandrogens in response to inhibition of the adrenal dehydrogenase system. The authors are grateful for the excellent technical assistance of Miss Esther Levy, Mrs. Gwendolyn Peyton, and Mrs. Barbara Sperling.

Effect of ergocornine on the luteal 20alpha-hydroxysteroid dehydrogenase in pseudopregnant and pregnant rats.

Abstract: Trattando ratte gravide o pseudogravide con ergocornina si puo osservare la comparsa dell'attivita 20α-idrossisteroide-deidrogenasica nei corpi lutei rispettivamente gravidici o pseudogravidici nei quali tale attivita normalmente manca. Perche questo effetto si manifesti sono necessari 2–3 giorni di trattamento. Si constata che l'ergocornina causa la comparsa dell'attivita enzimatica sopra indicata in qualsiasi periodo della pseudogravidanza, e nel periodo della gravidanza precedente l'impianto dell'uovo. L'ergocornina quindi agirebbe tramite l'ipofisi dalla cui regolazione dipende l'attivita 20α-idrossisteroide-deidrogenasica dell'ovaio.

Adrenal morphology and hydroxysteroid dehydrogenase enzymes in normal and intersex goats.

Abstract: A comparison of the adrenal morphology in 6 intersexes with that of normal aduItTgoats and kids indicated that the total size of the adrenal in the intersexes was much reduced as compared to that of adults. The intersex goats resembled week-old kids in total size and in cortex to medulla ratio. Histometric analysis on the relative thickness of the outermost cortical zone (zona glomerulosa) and the two inner zones (zona fasciculata and zona reticularis) revealed that the former in normal males occupied more than a third of the total cortical area whereas this zone in the kids and adult females approximated a fifth. The intersexes were in between the adult females and adult males in the relative distribution of their inner adrenal zones. Histochemical studies on hydroxysteroid dehydrogenase enzymes in the adrenals and the gonads of normal and intersex goats revealed localization of 3p-hydroxysteroid dehydrogenase in the zona reticularis in male goats and intersexes when androstenediol was used as the substrate whereas the intensity was much lower in the other two zones of intersexes as compared to those of normal goats. The ability of the adrenal enzymes to use pregnenolone as substrate was exhibited by all three cortical zones of all goats even though this reaction was more diffuse in adult goats whereas in intersexes and kids the reaction was localized at the junction of zona glomerulosa and zona fasciculata. The presence of 17 P-hydroxysteroid dehydrogenase was not demonstrable using either estradiol or testosterone as substrates in intersexes and normal adult males. Traces of this enzyme was detected in the adrenal cortex of the kids using testosterone as substrate and a similar weak reaction was noticeable with estradiol as substrate in the inner zones of females. The distribution of 3a-hydroxysteroid dehydrogenase in the Leydig cells was weak in male goats and intersexes when androstenediol was used as the substrate. In similar experiments using pregnenolone as substrate, a weak positive reaction was noted in the Leydig cells of intersexes and in the stroma of adult females but the reaction was negative in adult males and kids. As in their adrenals, the presence of 17 p-hydroxysteroid dehydrogenase was not detectable in the testes either with testosterone or estradiol as substrates. The marked hypoplasia and cellular damage affecting the adrenal cortex of intersexes and their closer resemblance to the kids in the distribution of hydroxysteroid dehydrogenase enzymes are considered to be indicative of a generalized interference with their steroid hormone-producing cells.

[40] 16α-hydroxysteroid dehydrogenase from rat kidney

Abstract: Publisher Summary 16α-Hydroxysteroid dehydrogenase from rat kidney is an adaptive enzyme regulated by sex hormones. Significant activity is found only in mature females, but the enzyme can be induced in castrated males or immature animals by estrogen administration. Testosterone inhibits this induction. Cat, chicken, and pigeon kidneys have lesser activity, and no striking sex difference is evident in these species. Mouse, hamster, guinea pig, rabbit, dog, pig, sheep, cow, and human kidneys show little or no activity. This chapter describes the method of assay, purification procedure, and properties of the enzyme. The chapter concludes with a discussion on other sex-dependent enzymes of steroid metabolism. All of these sex-dependent rat liver enzymes are localized in the microsomal fraction of differentially centrifuged homogenates. Solubilization attempts have been unsuccessful and most studies of these enzymes have utilized crude, washed particulate preparations.