Pituitary prolactin content and mammary development after chronic administration of prolactin.

Abstract

SummaryDaily injection of 1 or 10 mg of prolactin for 10 days or transplantation of anterior pituitaries (AP) to the kidney capsule for 14 days markedly decreased pituitary weight and prolactin content of mature virgin rats. Ovariectomy reduced prolactin content of pituitaries relative to intact controls, but ovariectomy plus transplantation of AP's reduced prolactin content even further. These results indicated that function of the auto-feedback control of prolactin can occur without the ovary. Prolactin injections and AP transplants increased total mammary DNA and RNA, but these increases were somewhat reduced in ovariectomized rats compared with intact rats. Exogenous prolactin reduced uterine and adrenal weights, stimulated body weight increases but had no significant effects on ovarian weights.