Serum Follicle-Stimulating Hormone and Luteinizing Hormone Concentrations During the Menstrual Cycle as Determined by Radioimmunoassays

Abstract

Human FSH and LH have been quantitated by specific radioimmunoassay techniques in sera obtained from 9 subjects during the course of 12 menstrual cycles. The time of ovulation was assessed by basal body temperatures and urinary pregnanediol excretion. Two peaks in FSH levels of similar magnitude were observed in 8 out of the 11 ovulatory cycles; the first during the early proliferative phase, the second at or near the time of ovulation. In one subject no midcycle peak was observed and in 2 others a third peak occurred during the latter part of the cycle. Prior to the next menses serum FSH fell to very low levels in all subjects. Serum LH showed a single midcycle peak in 10 of the 11 ovulatory cycles. Pre-ovulatory and post-ovulatory LH levels were of similar magnitude. The one anovulatory cycle was characterized by a delayed appearance of the first FSH peak and no LH peak of ovulatory magnitude.