Effects of bromocriptine-induced hypoprolactinaemia on the developmental pattern of androgen and LH levels in the male rat.

In immature male rats, receiving daily injections of bromocriptine (3 mg/kg bw), serum prolactin (Prl) remains low throughout development. In such hypoprolactinaemic males androgen variables are affected: a) the normally low pre-pubertal serum androgen (testosterone, dihydrotestosterone-T, DHT) is considerably increased, in correlation with a precocious development of the testicular Leydig cell population; b) the peri-pubertal rise of androgen is not prevented, but is is followed by significantly lower post-pubertal T, DHT levels, in correlation with moderately reduced Leydig cell counts and with strongly attenuated growth rates of sex accessory organs. Observed alterations of the post-natal androgen pattern cannot be related to LH changes since developmental LH values remained essentially unaltered. Results are in concordance with a marked age-dependent sensibility of androgen variables to a lack of Prl in the developing male.