Short-term effects of testolactone on human testicular steroid production and on the response to human chorionic gonadotropin.
Testicular responsiveness to a single dose of human chorionic gonadotropin was studied in five normal men before and during short-term treatment with an aromatization inhibitor, testolactone (TL). TL alone resulted in significant increases in the serum concentrations of progesterone, 17-hydroxyprogesterone, 17-hydroxypregnenolone, dehydroepiandrosterone, androstenedione, and the sulfate conjugates of pregnenolone, 17-hydroxypregnenolone and testosterone (T). Concentrations of 5-androstene-3 beta, 17 beta-diol and T remained unchanged, and those of estradiol (E2) decreased. TL had no major influence on serum luteinizing hormone, follicle-stimulating hormone, prolactin, or sex-hormone-binding globulin concentrations. During TL administration, human chorionic gonadotropin stimulation led to a significantly decreased E2 response, but the T response was unchanged. Alleviation of an inhibitory influence of E2 on the steroidogenic enzymes, especially 17,20-desmolase, was probably the reason behind the increased synthesis of several T precursors. In addition, TL appeared to have an inhibitory influence on the 17 beta-reduction of T precursors. TL resulted in increased serum concentrations of some steroid sulfates, but the mechanism of this effect remains unclear.
D000328:Adult; D000728:Androgens / Q000097:blood; D006063:Chorionic Gonadotropin; D004958:Estradiol / Q000097:blood; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D012738:Sex Hormone-Binding Globulin / Q000097:blood; D013738:Testolactone / Q000494:pharmacology*; D013739:Testosterone / Q000097:blood; D013997:Time Factors
D000728:Androgens; D006063:Chorionic Gonadotropin; D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D004958:Estradiol; D013738:Testolactone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone