Testosterone supplementation attenuates the antifertility effects of an LHRH agonist in male rhesus monkeys.

Continuous administration of LHRH agonists in high doses disrupts pituitary and testicular function, thus providing an approach to male fertility control. However, testosterone supplementation is required to prevent the side effects associated with low androgen concentrations resulting from chronic LHRH agonist treatment. Three adult male rhesus monkeys were treated with the LHRH agonist, Buserelin, using osmotic minipumps implanted subcutaneously. Testosterone was administered simultaneously via Silastic capsules. This combined treatment led to a marked decrease in testicular volume, and all animals were oligospermic within 8-15 weeks of treatment. Azoospermia was, however, not achieved even after 22 weeks of treatment although in a previous study in which the LHRH agonist had been administered alone, azoospermia had been achieved after 8-10 weeks. It is concluded that in this primate species testosterone supplementation attenuates the suppressive effects of LHRH agonist infusion on spermatogenesis.