A new transplantable prolactinoma, designated MtT/F84 has been serially passaged in female F344 rats. Persistently high levels of serum prolactin could be achieved in male F344 rats by MtT/F84 inoculating under the skin.
This investigation deals with the effects of hyperprolactinemia upon the accessory sexual organs of male rats during puberty. The weights and the concentrations of dihydrotestosterone (DHT) in the dorsal prostate increased significantly in rats with moderate hyperprolactinemia (756 ± 179 ng/ml), but they in rats with marked hyperprolactinemia (3612 ± 1089 ng/ml) were similar t.o those of control rats. In contrast, serum testosterone levels (0.52 ± 0/17 ng/ml) in those of hyperprolactinemic rats were significantly decreased compared to that of controls (1.11± 0.13 ng/ml).
These results suggested that the growth-promoting effect of prolactin on the rat prostate mediated through the action of androgen varied according to the degree of hyperprolactinemia.