Immunocytochemical analysis of the rat pineal gland using antisera generated against luteinizing hormone-releasing hormone (LHRH).

Seven different antisera generated against synthetic luteinizing hormone-releasing hormone (LHRH) were used to stain pineal gland and median eminence of the hypothalamus of normal rats. The LHRH immunogen complexes used to generate these antisera produced either N- or C-terminal directed antibodies or antisera that recognized both portions of the hormone molecule. Of these, four revealed LHRH-like immunoreactive material in the median eminence and pineal gland, two stained median eminence and not pineal, and one was positive in pineal only. These observations suggest that immunoreactive material in pineal gland may be an LHRH-like substance whose affinity characteristics are different from that of hypothalamic LHRH.