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PubMed2001

Estrogen regulates 11 beta-hydroxysteroid dehydrogenase-1 and -2 localization in placental syncytiotrophoblast in the second half of primate pregnancy.

We recently demonstrated that the 11 beta-hydroxysteroid dehydrogenase enzymes catalyzing cortisol-cortisone reduction (11 beta-hydroxysteroid dehydrogenase-1) and oxidation (11 beta-hydroxysteroid dehydrogenase-2) are located in different regions of the baboon and human placental syncytiotrophoblast. Moreover, there was a 2-fold increase in the ratio of 11 beta-hydroxysteroid dehydrogenase-2 to 11 beta-hydroxysteroid dehydrogenase-1 in syncytiotrophoblast membranes contiguous with the basal membrane (BMm) between mid and late baboon gestation. Our laboratories have also shown that estrogen regulates syncytiotrophoblast functional differentiation. Therefore, the current study determined whether the change in the ratio of 11 beta-hydroxysteroid dehydrogenase-2 to 11 beta-hydroxysteroid dehydrogenase-1 in the BMm was regulated by estrogen. Placentas were obtained on d 165 of gestation (term = d 184) from baboons that were untreated or were treated daily beginning on d 100 with the aromatase inhibitor CGS 20267, which reduced uterine and maternal serum E2 by more than 95% or with CGS 20267 plus E2 benzoate. Western blot analyses and immunofluorescence confirmed that in untreated controls the expression of 11 beta-hydroxysteroid dehydrogenase-1 was abundant in the microvillus membranes and considerably less in the BMm. In contrast, expression of 11 beta-hydroxysteroid dehydrogenase-2 was abundant in more internal regions of the syncytiotrophoblast, including the BMm, but was not detected in the microvillus membranes. The 11 beta-hydroxysteroid dehydrogenase-2 protein level was significantly decreased in the BMm of placentas from estrogen-suppressed baboons, resulting in a 2-fold decrease in the ratio of these enzymes in membranes juxta the fetal blood, and these changes were partially restored by CGS 20267 and E2. In contrast, estrogen had no effect on the ratio of 11 beta-hydroxysteroid dehydrogenase-2 to 11 beta-hydroxysteroid dehydrogenase-1 in whole villous homogenate or the micro-villus membranes. Collectively, these results indicate that estrogen regulates the developmental increase in the ratio of 11 beta-hydroxysteroid dehydrogenase-2 to 11 beta-hydroxysteroid dehydrogenase-1 in syncytiotrophoblast membranes juxta fetal blood, providing the subcellular architectural mechanism responsible for the previously demonstrated estrogen-dependent switch in transplacental glucocorticoid metabolism that regulates maturation of the primate fetal pituitary-adrenocortical axis.

11-beta-Hydroxysteroid Dehydrogenase Type 2↗
PubMed1988

Lyophilized Clostridium perfringens 3 alpha- and Clostridium bifermentans 7 alpha-hydroxysteroid dehydrogenases: two new stable enzyme preparations for routine bile acid analysis.

Preparations of 3 alpha-hydroxysteroid dehydrogenase (EC 1.1.1.50) from Clostridium perfringens were successfully lyophilized into a stable powder form. Purification of the enzyme was achieved using triazine dye affinity chromatography. C. perfringens 3 alpha-hydroxysteroid dehydrogenase was purified 24-fold using Reactive Red 120 (Procion Red) -cross-linked agarose (70% yield). Quantitative measurement of bile acids with the purified enzymes, 3 alpha-hydroxysteroid dehydrogenase and 7 alpha-hydroxysteroid dehydrogenase (EC 1.1.1.159) from Clostridium bifermentans (strain F-6), was achieved spectrophotometrically. Standard curves with chenodeoxycholic acid (CDC) and cholic acid were linear within a concentration range of 20-100 microM. Analysis of mixtures of ursodeoxycholic acid and CDC showed the additive nature of the 3 alpha-hydroxysteroid dehydrogenase and showed also that 7 alpha-hydroxyl groups were independently quantified by the 7 alpha-hydroxysteroid dehydrogenase. Bile acids in Folch extracts of human bile samples were measured using purified preparations of Pseudomonas testosteroni 3 alpha-hydroxysteroid dehydrogenase, C. perfringens 3 alpha-hydroxysteroid dehydrogenase, Escherichia coli 7 alpha-hydroxysteroid dehydrogenase and C. bifermentans (strain F-6) 7 alpha-hydroxysteroid dehydrogenase. Statistical comparison validated the use of C. perfringens 3 alpha- and C. bifermentans 7 alpha-hydroxysteroid dehydrogenases for the quantification of bile acids in bile.

3-Hydroxysteroid Dehydrogenases↗
PubMed1994

Phosphorylation of 17 beta-hydroxysteroid dehydrogenase in BeWo choriocarcinoma cells.

OBJECTIVE: The purpose of this study was to test whether 17 beta-hydroxysteroid dehydrogenase might exist in a phosphorylated form. STUDY DESIGN: Phosphorylation of 17 beta-hydroxysteroid dehydrogenase was evaluated in BeWo choriocarcinoma cells. The phosphorylation of 17 beta-hydroxysteroid dehydrogenase expressed in Escherichia coli as a glutathione transferase fusion protein was also studied. RESULTS: Human BeWo choriocarcinoma cells were metabolically labeled with phosphorus 32 orthophosphate. Immunoprecipitates were prepared with rabbit anti-17 beta-hydroxysteroid dehydrogenase antiserum from the labeled cells and separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A phosphorylated protein with a molecular size of 35 kd was obtained from anti-17 beta-hydroxysteroid dehydrogenase immunoprecipitates, which suggested that 17 beta-hydroxysteroid dehydrogenase was phosphorylated in BeWo cells. The predominant phosphoamino acid was phosphoserine. 17 beta-Hydroxysteroid dehydrogenase expressed in E. coli as a glutathione transferase fusion protein was a substrate of protein kinase A in vitro. Protein kinase A phosphorylated the recombinant 17 beta-hydroxysteroid dehydrogenase exclusively on serine. Incubation of BeWo cell lysates with bacterial alkaline phosphatase led to a decrease in the oxidative activity of 17 beta-hydroxysteroid dehydrogenase. Incubation of the alkaline phosphatase inhibitor levamisole with BeWo cell lysates resulted in a higher estradiol-to-estrone conversion rate, compared with cell lysates without any treatment. CONCLUSION: Our data suggest that 17 beta-hydroxysteroid dehydrogenase may exist in phosphorylated forms and that phosphorylation may regulate the activity of 17 beta-hydroxysteroid dehydrogenase in vivo.

17-Hydroxysteroid Dehydrogenases↗
PubMed1976

3alpha-, 7alpha- and 12alpha-hydroxysteroid dehydrogenase activities from Clostridium perfringens.

25 strains of Clostridium perfringens were screened for hydroxysteroid dehydrogenase activity; 19 contained NADP-dependent 3alpha-hydroxysteroid dehydrogenase and eight contained NAD-dependent 12alpha-hydroxysteroid dehydrogenase active against conjugated and unconjugated bile salts. All strains containing 12alpha-hydroxysteroid dehydrogenase also contained 3alpha-hydroxysteroid dehydrogenase although 12alpha-hydroxysteroid dehydrogenase was invariably in lesser quantity than the 3alpha-hydroxysteroid dehydrogenase. In addition, 7alpha-hydroxysteroid dehydrogenase activity was evident only when 3alpha, 7alpha, 12alpha-trihydroxy-5beta-cholanoate was substrate but notably absent when 3alpha, 7alpha-dihydroxy-5beta-cholanoate was substrate. The oxidation product 12alpha-hydroxy-3, 7-diketo-5beta-cholanoate is rapidly further degraded to an unknown compound devoid of either 3alpha- or 7alpha-OH groups. Group specificity of these enzymes was confirmed by thin-layer chromatography studies of the oxidation products. These enzyme systems appear to be constitutive rather than inducible. In contrast to C. perfringens. Clostridium paraputrificum (five strains tested) contained no measurable hydroxysteroid dehydrogenase activity. pH studies of the C. perfringens enzymes revealed a sharp pH optimum at pH 11.3 and 10.5 for the 3alpha-OH- and 12alpha-OH-oriented activities, respectively. Kinetic studies gave Km estimates of approx. 5 X 10(-5) and 8 X 10(-4) M with 3alpha, 7a-dihydroxy-5beta-cholanoate and 3alpha, 12alpha-dihydroxy-5beta-cholanoate as substrates for two respective enzymes. 3alpha-hydroxysteroid dehydrogenase was active against 3alpha-OH-containing steroids such as androsterone regardless of the sterochemistry of the 5H (Both A/B cis and A/B trans steroides were substrates). There was no activity against 3beta-OH-containing steroids. The 3alpha- and 12alpha-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.

Androsterone↗
PubMed1996

Unusual evolution of 11beta- and 17beta-hydroxysteroid and retinol dehydrogenases.

11beta-hydroxysteroid dehydrogenases regulate glucocorticoid concentrations and 17beta-hydroxysteroid dehydrogenases regulate estrogen and androgen concentrations in mammals. Phylogenetic analysis of the sequences from two 11beta-hydroxysteroid dehydrogenases and four mammalian 17beta-hydroxysteroid dehydrogenases indicates unusual evolution in these enzymes. Type 1 11beta- and 17beta-hydroxysteroid dehydrogenases are on the same branch; Type 2 enzymes cluster on another branch with beta-hydroxybutyrate dehydrogenase,11-cis-retinol dehydrogenase and retinol dehydrogenase; Type 3 17beta-hydroxysteroid dehydrogenase is on a third branch; while the pig dehydrogenase clusters with a yeast multifunctional enzyme on a fourth branch. Pig 17beta-hydroxysteroid dehydrogenase appears to have evolved independently from the other three 17beta-hydroxysteroid dehydrogenases; in which case, the evolution of 17beta-hydroxysteroid dehydrogenase activity is an example of functional convergence. The phylogeny also suggests that independent evolution of specificity toward C11 substituents on glucocorticoids and C17 substituents on androgens and estrogens has occurred in Types 1 and 2 11beta- and 17beta-hydroxysteroid dehydrogenases.

11-beta-Hydroxysteroid Dehydrogenases↗