Purification and properties of 17 beta-hydroxy-C19-steroid dehydrogenases of adult male guinea pig kidney.

The 17 beta-hydroxy-C19-steroid dehydrogenase activity of adult male guinea pig kidney was separated into one isolated and two contiguous enzymatically pure fractions by submitting the cytosol to (NH4)2SO4 (40-80% saturation) precipitation, Sephadex G-75 filtration, and DEAE-Sephadex A-50 and CM-Sephadex C-50 chromatography. Further DEAE-Sephadex A-50 and CM-Sephadex C-50 chromatography separated eight isozymes, which were divided into four groups in accordance with their behavior on chromatography and mobility on gel electrophoresis. The molecular weights of the purified enzymes were identical by Sephadex filtration (33,000) and SDS gel electrophoresis (34,000). Two of the enzymes were separated by SDS gel electrophoresis into two subcomponents of 23,000 and 11,000 daltons. The amino acid composition, Km values, and coenzyme and substrate specificities of the enzymes (except one) were very similar. The pI values varied from 5.1-6.4 HgCl2 and PCMB inhibited enzyme activity, but prior addition of cysteine prevented the inhibition. The presence of phosphate or pyrophosphate greatly enhanced the trace of DPN+ -linked activity. The heterogeneity was due to at least two factors. Rapid (within 3 h) preparation of the cytosol in 7 mM 2-mercaptoethanol yielded one intense and one minor enzyme band on gel electrophoresis. Omission of the mercaptoethanol resulted in the appearance of three enzyme bands, which were reversible on the addition of 2-mercaptoethanol. Storage of the cytosol at 4 or -20 C in the absence or presence of 7 mM 2-mercaptoethanol and of the kidney before extraction also resulted in the exhibition of enzyme bands which were not reversible on addition of 2-mercaptoethanol. The purified enzymes exhibited only a single form on storage at -20 C with 2-mercaptoethanol, but multiple forms appeared when the mercaptoethanol was removed by dialysis. The multiple forms were reverted to a single form on addition of mercaptoethanol.

Androgen regulation of transferase II activity in the mouse kidney.

Castration of adult male mice reduced the ability of the transferase factors of the kidney to stimulate amino acid incorporation by polysomes in vitro. The administration of testosterone propionate (TP) to the mice for 11 days greatly increased the activity of the transferase fraction. The changes occurred only in transferase II. The induction of the increase in transferase activity was evident 24 h after the injection of TP and required a lag period of at least 12 h. The concentration of pH 5 enzymes (protein) was slightly decreased by castration and was restored by TP administration. The radioactivity in the hot perchloric acid extract of the protein after amino acid incorporation was increased but the activity of the pH 5 enzyme fraction on amino incorporation was not significantly changed by androgen administration.

Metabolites of testosterone: significance in the vital economy.

Testosterone is metabolized by practically every tissue in the body to a large variety of related steroids. The metabolites vary with each tissue and appear to be formed to meet the specific needs of the particular tissue and animal. The many biologic actions of testosterone do not change in parallel in the various metabolites. Many of the metabolites show interesting differences in their relative biologic effects. A large number and variety of steroid-metabolizing enzymes (oxidoreductases, reductases, hydroxylases, aromatases) are involved. Some have been partially purified. The 17 beta-oxidoreductases of the cytosol of the guinea pig liver and kidney have been purified and characterized.

Anabolic-androgenic steroids: In cell culture.

Testosterone and related steroids at physiological concentrations positively stimulate in cell culture a number of reactions in a variety of tissues from different species of animals. Cells maintained in cell culture provide a means to study toxic effects in target organs and also the mechanism of action of these steroids.

Anabolic-androgenic steroids: in cell culture.

Testosterone and related steroids at physiological concentrations positively stimulate in cell culture a number of reactions in a variety of tissues from different species of animals. Cells maintained in cell culture provide a means to study toxic effects in target organs and also the mechanism of action of these steroids.