Effect of LHRH agonist (buserelin) on pulsatile secretion of LHRH and LH

The LHRH agonist buserelin was administered intranasally to eight patients with endometriosis in doses of 300, 600 or 900 micrograms/day for six months. In all patients buserelin clearly suppressed ovulation. In the patients treated with 900 micrograms/day, estradiol levels declined to less than 30pg/ml, and LH release in response to LHRH testing decreased markedly after 2 months of treatment. A mild decrease in LH release was noted in the premarin test at the end of the treatment. At the end of buserelin treatment baseline levels of plasma LHRH, LHRH pulse amplitude and frequency were not lowered. However, baseline levels of plasma LH and LH pulse amplitude decreased. These results indicate that buserelin may act to decrease pituitary response to LHRH.