Stimulation of luteinizing hormone (LH) and follicle-stimulating hormone by (D-Leu6, des-Gly10-NH2)-LH-releasing hormone ethylamide after subcutaneous, intravaginal, and intrarectal administration to women.

Women, most of whom had regular menstrual cycles, were administered D-Leu6,des-Gly10-NH2)-luteinizing hormone-releasing hormone (LH-RH) ethylamide (D-Leu6-LH-RH-EA)via different routes during the early or midfollicular phase of the cycle. Plasma LH, follicle-stimulating hormone (FSH), and estrogen levels were determined by radioimmunoassay before and after administration of D-Leu6-LH-RH-EA. plasma LH and FSH increased and reached peak levels 3 to 4 hours and 3 to 6 hours, respectively, after subcutaneous injection of 25 mug of the analog of LH-RH. Intravaginal or intrarectal application of 2 mg of D-Leu6-LH-RH-EA also increased plasma LH and FSH levels in most of the women, but the magnitude of the rise, the time of initiation of response, and the peak level varied among the women. The plasma estrogen level also rose after administration via either route.