THE EFFECT OF HYPOPROLACTINEMIA ALONE AND IN COMBINATION WITH CYCLOSPORINE ON ALLOGRAFT-REJECTION

Recent evidence suggests that prolactin has a role in regulating immune function. Hypophysectomy or administration of bromocriptine results in suppression of the immune response, which is reversed by the administration of prolactin. Hypoprolactinemia has been shown to augment the immunosuppressive effect of cy- closporine. We studied the effect of hypoprolactinemia induced by a new drug, CQP 201-403, on the survival of heterotopic cardiac allografts in the rat and the ability of peripheral blood lymphocytes to respond in vitro to plant mitogens. CQP treatment alone produced a small increase in graft survival but no change in lymphocyte in vitro proliferation (P<0.05). CQP treatment greatly enhanced the immunosuppressive effect of cyclosporine on graft rejection and in vitro lymphocyte function (P<0.02). We conclude that modulation of prolactin may be a useful adjunct to cyclosporine immunosuppression. © 1990 by Williams & Wilkins.