title: Metabolism of [4-14C]testosterone and precursors by homogenates of rat testes after chronic LHRH-treatment.
abstract: Adult male rats were injected daily for 8 days with an LHRH agonist. Twenty-four hours after the last injection testes-homogenates were incubated in the presence of a 4-14C-labeled steroid, either progesterone, 17 alpha-hydroxyprogesterone, dehydroepiandrosterone, androstenedione or testosterone. The activity of several enzymes involved in the androgen biosynthetic pathway was inferred from the amount of metabolites produced under these conditions. After LHRH-treatment a significant increase in the 17,20-lyase activity was observed without any significant change in the activity of 17 alpha-hydroxylase, 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4-isomerase and 17 beta-hydroxysteroid dehydrogenase. The results of the experiments indicate that the decreased testosterone secretion observed in rats after chronic LHRH-administration is not due to an inhibition of the enzyme-systems studied.
mesh_terms: D000735:Androstenedione / Q000378:metabolism; D000818:Animals; D013196:Dihydrotestosterone / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D006908:Hydroxyprogesterones / Q000378:metabolism; D008297:Male; D011374:Progesterone / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013737:Testis / Q000201:enzymology / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism*
chemical_list: D006908:Hydroxyprogesterones; D013196:Dihydrotestosterone; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D000735:Androstenedione; D011374:Progesterone