Somatostatin inhibits prolactin release from the lactotroph primed with oestrogen and cyproterone acetate in man.

The present study investigated the effect of administration of somatostatin (SRIF) on the release of prolactin in men. No effect was observed when SRIF was administered to eugonadal men. Release of prolactin was inhibited, however, when SRIF was administered to oestrogen-treated agonadal subjects (male-to-female trans-sexuals) and to an even greater degree when subjects had been pretreated with a combination of oestrogen and cyproterone acetate. This is consistent with findings in the rat. Thus in man, as in the rat, SRIF can inhibit prolactin secretion, but only after treatment with oestrogen.