Regulation of immunity in rats by lactogenic and growth hormones.

Antibody formation to sheep red blood cells and the development of contact dermatitis in response to dinitrochlorobenzene are impaired in hypophysectomized (Hypo-X) rats. Rat prolactin, rat growth hormone, bovine prolactin, bovine growth hormone, human placental lactogen and human growth hormone all restored the immunological competence of Hypo-X animals. The possible mechanism of action of these hormones on immune reactions is discussed.