Showing papers on "Hydroxysteroid dehydrogenase published in 1977"
TL;DR: Eubacterium lentum (ATCC No. 25559) was shown to contain 3α- and 12α-hydroxysteroid dehydrogenases both of which were NAD-dependent and active against conjugated and unconjugated bile salts.
42 citations
TL;DR: It is concluded that preextraction and/or the use of an inhibitor of alcohol dehydrogenase (1,10-phenanthroline) has to be performed and specifications for the ideal solvent of steroid substrates in the histochemical practice are proposed.
Abstract: By recording the incubation time needed for initial appearance of the red and blue formazans the reliability of the histochemical method for 3β-HSD was investigated:
25 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: A protein fraction containing the enzyme corresponding to the fastest migrating band and devoid of the other hydroxysteroid dehydrogenase activities has been obtained, and appears to be distinct from the previously isolated 3(17) beta-hydroxysteroid dehydration.
21 citations
TL;DR: It was concluded that the active form of the dehydrogenase occurs as its monomer with sedimentation coefficient 3.11 s and molecular weight, 35,400 daltons.
8 citations
TL;DR: The activity pattern of NAD/NADP-linked 11β-hydroxysteroid dehydrogenase (HSD) in the submandibular gland of the rat was re-evaluated using several control experiments and 12β-HSD was found to be primarily NAD-dependent.
Abstract: The activity pattern of NAD/NADP-linked 11β-hydroxysteroid dehydrogenase (HSD) in the submandibular gland of the rat was re-evaluated using several control experiments The incubation time needed for the initial appearance of red and blue formazans was used to investigate the activity of NAD-dependent 11β-HSD in control and cortisol-treated rats The following results were obtained (1) Prefixation of small tissue blocks with 1% w/v methanol-free formaldehyde (pH 72) for up to 20 min preserved morphological integrity and maximal enzyme activity The substantivity of formazans was enhanced (2) The substantivity of Nitro BT was highly variable The implication of this forin situ localization of enzymes was analysed (3) Pretreatment with acetone and application of phenanthroline was necessary to avoid a false positive reaction caused by alcohol dehydrogenase (4) No diffusion of 11β-HSD was noticed within 30 min of incubation, nor was rediffusion of reduced intermediates seen (5) With either NAD or NADP as coenzyme, 11β-HSD was localized in the striated, intralobular, interlobular, interlobar, and main duct (6) 11β-HSD was found to be primarily NAD-dependent (7) With DMF or DMSO as solvent, the rate of utilization of substrates was as follows: Cortisol=11β-hydroxyandrostendione>11β-hydroxyprogesterone Aldosterone was utilized very poorly, if at all (8) After injection (ip) of a single pharmacological dose of cortisol, the activity of NAD-linked 11β-HSD was significantly increased 24 h later (9) NADH-tetrazolium reductase was not inhibited by levamisole (10) Distinct NADPH-tetrazolium reductase activity was localized in the apical part of cells (or cell membranes) of the interlobar ducts and the main duct
8 citations
TL;DR: The NADP-dependent microsomal kidney enzymes, 3alpha- and 20beta-hydroxysteroid dehydrogenase (HSDH), which exhibit considerable sex differences in their activities, were investigated after interference with the pituitsary-gonad and pituitary-adrenal systems.
Abstract: The NADP-dependent microsomal kidney enzymes, 3alpha- and 20beta-hydroxysteroid dehydrogenase (HSDH), which exhibit considerable sex differences in their activities (male:female activity ratios, 16:1 and 30:1 respectively), were investigated after interference with the pituitary-gonad and pituitary-adrenal systems. Prepubertal gonadectomy as well as hypophysectomy of mature male rats led to a decline in HSDH activity to almost that found in the normal female rat, whereas activities in female rats were unaffected. Testosterone induced typical male 3alpha-HSDH activity in both gonadectomized and hypophysectomized rats of either sex. Administration of 5alpha-dihydrotestosterone (5alpha-DHT) or 5alpha-androstane-3alpha, 17beta-diol to hypophysectomized male rats was equally effective in restoring full 3alpha- and 20beta-HSDH activities whereas 5alpha-androstane-3beta, 17beta-diol was less effective and dehydroepiandrosterone was ineffective. Simultaneous administration of cyproterone acetate did not block the inductive action of 5alpha-DHT. Administration of chorionic gonadotrophin, pregnant mare serum gonadotrophin or a combination of luteinizing hormone and follicle-stimulating hormone to hypophysectomized male rats all led to parallel increases in the weight of the seminal vesicles and in both renal enzyme activities; administration of growth hormone, prolactin or thyroid-stimulating hormone was ineffective. Adrenalectomy of gonadectomized, but not of hypophysectomized male rats, caused a further drop in activity to the normal female level. Adrenalectomy of otherwise intact rats did not affect either enzyme activity. The hypophysis was involved in the regulation of the two NADP-dependent renal HSDH activities through its gonadotrophic function in male rats; adrenal secretions were of little physiological significance.
7 citations
TL;DR: It is established that DHT (3 μM) is almost completely metabolized to Adiol during a 2-h incubation at 0 °C even in the absence of added coenzymes.
Abstract: In our studies of the binding of steroids in rat skeletal muscles, we have shown the existence of a saturable '4S' dihydrotestosterone-binding protein of low affinity (Kd = 1.16 × 10−6 M). Competit...
6 citations
TL;DR: Progestin-induced changes in 17β hydroxysteroid dehydrogenase activity may not be as important in the regulation of androgen action in prostatic tissue as they appear to be in theregulation of estrogenic action in human endometrium.
6 citations
Journal Article•
TL;DR: Activity of delta5,3beta-hydroxysteroid dehydrogenase was demonstrated either in cells in suspension prior to the culture or in cultured cells, while a majority of cells in culture contained active enzyme in the cytoplasm.
Abstract: Leydig cells isolated from mouse testes were cultured as monolayers for 18 days. Activity of delta5,3beta-hydroxysteroid dehydrogenase (delta5,3beta-OH-SDH) was demonstrated either in cells in suspension prior to the culture or in cultured cells. The dynamics of the enzyme activity in cultured cells was investigated for 11 days. Approximately 50% of cells in suspension prior to culture showed the activity of delta5,3beta-OH-SDH, while a majority of cells in culture contained active enzyme in the cytoplasm.
6 citations
Journal Article•