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.

Cyproterone acetate induced changes in the behaviour of hydroxysteroid dehydrogenases in rat Leydig cells during perinatal development.

Abstract: The influence of cyproterone acetate (CA) upon the behaviour of hydroxysteroid dehydrogenases (HSDH) in the Wistar rat Leydig cells was investigated during the perinatal phase with the help of enzymhistochemical cum morphometrical techniques. The pregnant rats as well as their offsprings were injected with CA (dosage: 35 mg/kg body wt) sc, daily from 14 fetal day upto 31 postnatal day (p.n.d.). The animals were killed on 5, 20, and 32 p.n.d.; the enzymhistochemical reactions for 3-beta-HSDH, 11-beta-HSDH, 17-HSDH and 3-alpha-HSDH were performed in the cryostat sections of the testis, and the morphometric evaluation of HSDH positive Leydig cells was carried out. On 5 p.n.d. the activity of 17-beta-HSDH was slightly impaired in the intertubular Leydig cells of the CA treated animals. On 20 p.n.d., CA prevented nearly completely the HSDH activity in the newsly built peritubular Leydig cells; the activities of 3-beta-HSDH, 17-beta-HSDH, and 3-alpha-HSDH resided mainly in the intertubular Leydig cells. On 32 p.n.d. the HSDH activities in the Leydig cells were observed in the control as well as in treated animals. It seems that the differentiation of peritubular Leydig cells, and thereby the steroid production, is delayed by CA, but not entirely blocked.

Immunocytochemical localization of 17β-hydroxysteroid dehydrogenase in porcine testis

Abstract: The immunocytochemical localization of 17β-hydroxysteroid dehydrogenase (17β-HSD) in porcine testes was examined by applying an indirect-immunofluorescence method using an antiporcine testicular 17β-HSD antibody. Only the Leydig cells located in the interstitial tissue exhibited a positive immunoreaction for 17β-HSD: the germ cells and Sertoli cells located in the seminiferous tubules were entirely negative. These results suggest that, in porcine testis, the biosynthesis of testicular testosterone, the final step of which is the conversion of androstenedione to testosterone, takes place in the Leydig cells.

Modulation of 3 alpha-hydroxysteroid dehydrogenase activity by the redox state of glutathione.

Abstract: 3 alpha-Hydroxysteroid dehydrogenase (EC 1.1.1.50), purified to homogeneity from rat liver, was strongly inactivated by incubation with a disulfide such as GSSG, L-cystine or L-cystamine, as well as an SH-reagent such as DTNB (5,5'-dithiobis(2-nitrobenzoic acid)), NEM (N-ethylmaleimide) or iodoacetic acid. The inactivation advanced with incubation time. Coenzyme (NADP+) completely protected the enzyme from this inactivation by disulfides, but neither of the substrates (androsterone and benzenedihydrodiol) did. The activity of inactivated enzyme was restored by treatment with thiols such as DTT (dithiothreitol) or GSH. In the GSH/GSSG redox buffer, the enzyme existed in an equilibrium between active (reduced) and inactive (oxidized) forms.

Absence of type 1 11-hydroxysteroid dehydrogenase enzyme in koala liver

Abstract: The 11beta-hydroxysteroid dehydrogenases (11beta-HSDs) interconvert 11beta-hydroxysteroids such as cortisol into 11-oxosteroids such as cortisone. In most mammals, 11beta-HSD 1 is expressed predominantly in the liver and is active in both the oxidative (cortisol to cortisone) and dehydrogenase (cortisone to cortisol) directions, whilst 11beta-HSD 2 is expressed predominantly in the kidney and functions as a pure oxidative enzyme. We have investigated 11beta-HSD 1 activity in the Australian koala (Phascolarctos cinereus) and have found no activity (either reductive or oxidative) in hepatic microsomes. Immunoblot analysis of koala hepatic microsomes, using an 11beta-HSD 1 antibody raised against the mouse enzyme, failed to identify immunoreactive protein. Reverse transcriptase-polymerase chain reaction (RT-PCR) of koala liver mRNA and genomic PCR using primers designed against highly conserved regions of 11beta-HSD 1 nucleotide sequences were also negative. Furthermore, Southern and Northern blot analysis of koala genomic DNA and mRNA, respectively, confirmed that the koala lacks the 11beta-HSD 1 gene and gene transcript. These results support the fact that the lack of hepatic 11beta-HSD 1 activity in the koala is due to the absence of the 11beta-HSD 1 gene, and this absence is novel among mammalian species studied to date.