[Effect of gonadectomy and luliberin on the gonadotropic function of the hypophysis in Papio hamadryas].

A comparative study was made of the effect of LH-RH on the hypophyseal reactivity in intact and castrated male papio hamadryas. Hypophysis gonadotropic function was evaluated by the content of the biologically active luteinizing hormone in the peripheral blood plasma which was determined by an in-vitro biological method. Bilateral gonadectomy caused an increase in the luteinizing hormone concentration by an average of 600% in this species of apes. The hormone level got stable at maximum values in the course of 3 days. After administration of exogenous LH-RH the maximum LH concentration both in intact and castrated animals was recorded 30 min after the administration of a hypothalamic mediator. Basal and LH-RH stimulated values of the LH concentration were higher in castrated apes. However the period of a hormone concentration increase in the peripheral blood of intact animals exceeds the response time in castrated males. The authors discuss possible mechanisms of change in the hypophyseal reactivity to LH-RH under conditions of surgical disconnection of testicle function.