Rapid endocrine effects of tamoxifen and testolactone in prostatic carcinoma patients.
The short-term (6-day) endocrine effects of tamoxifen and testolactone were investigated in men with prostatic carcinoma. Tamoxifen treatment (20 mg/day) did not affect the gonadotropin levels, but it temporarily increased prolactin, induced sex hormone-binding globulin production, and suppressed peripheral serum progesterone, 17-hydroxyprogesterone, androstenedione, testosterone, and 5 alpha-dihydrotestosterone concentrations. These changes were attributed to the estrogenic properties of tamoxifen, since no changes in peripheral serum estradiol concentrations were observed. Testolactone (1000 mg/day) decreased peripheral estradiol concentrations by 50% and increased the concentrations of the neutral steroids measured. The increases in serum FSH and LH were very small. This study corroborates the early estrogen-like action of tamoxifen, and the experiment with testolactone further suggests that endogenous estradiol has physiological functions in man, regulating gonadotropin and androgen production.
D000368:Aged; D004702:Endocrine Glands / Q000187:drug effects*; D004958:Estradiol / Q000097:blood; D006065:Gonadotropins, Pituitary / Q000097:blood; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000097:blood*; D013256:Steroids / Q000097:blood; D013629:Tamoxifen / Q000494:pharmacology*; D013738:Testolactone / Q000494:pharmacology*
D006065:Gonadotropins, Pituitary; D013256:Steroids; D013629:Tamoxifen; D004958:Estradiol; D013738:Testolactone