Increased serum prolactin induced in hypophysectomized rats bearing ectopic pituitaries.

Abstract

SummaryA radioimmunassay was developed for quantifying rat prolactin in blood serum, but the assay detected small amounts of immunoreactive prolactin in serum from hypophysectomized (Hx) rats. Prolonged anesthesia of these Hx rats with urethane significantly decreased their serum prolactin values, while prolonged anesthesia with pentobarbital (PB) had no significant effect.Transplantation of pituitary tissue (AP) to the renal capsule of Hx rats elevated serum prolactin, and this effect was produced with as little as I/8 AP. Prolonged PB or urethane anesthesia combined with multiple blood sampling of Hx rats bearing ectopic AP significantly increased serum prolactin. The absence of stable prolactin concentrations an these rats suggests that prolactin release by ectopic AP may still be influenced by hypothalamic hypophysiotrophic hormones in the systemic circulation.