Metabolism of androstenedione by guinea-pig peritoneal macrophages: synthesis of testosterone and 5 alpha-reduced metabolites.
Androstenedione metabolizing enzymes present in guinea-pig peritoneal macrophages were investigated using tritium-labeled androstenedione as the substrate. We found that the metabolites of [3H]-androstenedione produced by these macrophages were testosterone, 5 alpha-androstane-3,17-dione, isoandrosterone, androsterone, 5 alpha-dihydrotestosterone, 5 alpha-androstane-3 alpha, 17 beta-diol and 5 alpha-androstane-3 beta, 17 beta-diol. The rates of metabolite formation remained linear as a function of time of incubation for approximately 30 min and with macrophage number up to 2 x 10(7) cells per ml. The formation of these metabolites in indicative that the following androstenedione metabolizing enzymes are present in guinea-pig peritoneal macrophages: 5 alpha-reductase, 3 alpha-hydroxysteroid oxidoreductase, 3 beta-hydroxysteroid oxidoreductase and 17 beta-hydroxysteroid oxidoreductase. It is possible, therefore, that the macrophage, in vivo, may play a role in the metabolism of blood-borne androstenedione to potent androgens. These hormones are important in the regulation of many biological processes, possibly including the activity of the macrophage itself.
D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000378:metabolism; D000735:Androstenedione / Q000378:metabolism*; D000818:Animals; D001202:Ascitic Fluid / Q000166:cytology; D002852:Chromatography, Ion Exchange; D006168:Guinea Pigs; D008264:Macrophages / Q000378:metabolism*; D013739:Testosterone / Q000096:biosynthesis
D013739:Testosterone; D000735:Androstenedione; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase