The role of androgens in adolescent cycles

Abstract

Serum steroids and gonadotrophins were measured at days 6–9 and 20–23 of 209 adolescent cycles. Based on serum progesterone levels, about 80% of the cycles during the first gynecological year (years since menarche) were anovulatory, during the third, about 50%, and 6.0–7.5 years after menarche, 15% of the cycles were anovulatory. Testosterone was higher at days 6–9 and 20–23 in anovulatory cycles as compared with ovulatory ones. In addition, serum testosterone was higher in the latter part of the anovulatory cycles as compared to the beginning of the cycles. The pattern of serum androstenedione was very similar to that of testosterone. The only difference was that there were no significant differences between the ovulatory and anovulatory cycles in its concentration in samples taken at the beginning of the cycles. In the case of 5α-dihydrotestosterone, no significant differences were observed in its concentration between ovulatory and anovulatory cycles. However, its concentration was significantly higher in the luteal phase of ovulatory cycles as compared with the follicular phase. The midcycle increases in serum FSH and LH, seen in ovulatory cycles, occasionally appeared in anovulatory cycles, but were usually absent. The increase in serum LH in the latter part of the anovulatory cycles was converted to a decrease in ovulatory cycles. In addition, concentrations of FSH remained higher at the end of anovulatory cycles compared with the ovulatory ones. Animal experiments and evidence from clinical conditions associated with increased androgen production suggest that androgens have regulatory functions in the development of follicles. This evidence, put together with our present findings, suggests that the cyclic element in female reproduction is primarily ovarian in origin and is introduced by an androgen effect on maturing follicles. According to this concept, production of androgens by the first maturing follicles leads to a certain critical androgen concentration, resulting in follicular arrest and decreased steroid production. Repetitions of this process finally lead to synchronization of the endocrine feed-back processes operative during the reproductive life of woman.