Influence of Exogenously Administered Melatonin on the Reproductive System and Prolactin Levels in Underfed Male Rats1

Abstract

After continued immunization of 3 male rhesus monkeys (Macaca mulatta) against luteinizing hormone releasing hormone (LHRH), serum titers of LHRH antibodies rose. When these titers reached an effective level, dramatic decreases in serum concentrations of luteinizing hormone (LH) and testosterone (T) were observed. As antibody levels declined, serum LH and T levels returned to preimmunization values. Repeated immunization throughout a 12 month period caused a decline in testicular weight and steroid production, a decrease in anterior pituitary LH concentrations, a reduction in hypothalamic LHRH content and histological changes within the pituitary and testes. Injection of Freund’s complete adjuvant into 3 other males caused no change in these parameters of reproductive function.