The effect of ovine prolactin on the epididymal sialic acid concentration in male rats.

1. Previous experiments have shown that the level of sialic acid in the epididymis is influenced by factors originating in the testis. 2. To exclude interference from these factors, both orchidectomized and duct-ligated rats were used to study the potential role of prolactin in the epididymis. 3. When ovine prolactin was injected in orchidectomized rats, a dose-related increase in the level of sialic acid was observed in the epididymis. 4. That this action of prolactin is independent of androgen was confirmed by studies using bromocriptine, which decreases circulating endogenous prolactin. 5. The physiological role(s) of epididymal sialic acid production in response to prolactin remain to be established.