Figure 1.

Study protocol diagram. Follicular phase administration of transdermal estradiol was used to induce LH secretion 48 hours later as a model of the midcycle LH surge in women. Ten healthy women were administered NK3R antagonist AZD4901 from cycle day 4–6 for 6 days, matched to 10 women having no treatment. Transdermal estradiol was applied after 5 days; 24 hours later, women were randomized to 7 hour of kisspeptin-10 (Kp-10) or vehicle infusion, returning in a subsequent cycle for the alternate infusion. Reproductive hormones were measured throughout the study and LH pulsatility assessed during 10 minutes of blood sampling for 8 hours.