Activins, on the other hand, increase FSH secretion. Both compounds have other endocrine, paracrine, and probably autocrine influences, but their exact roles in the menstrual cycle have yet to be defined. A small amount of testosterone is secreted directly by the ovary. Androstenedione is also an important ovarian androgen. The principal role of ovarian androgens may well be within the ovary, but secreted androstenedione serves as a prohormone for peripheral conversion to testosterone or estrone.
Ovarian androgens contribute to the anabolic state in females.
In excess, they inhibit the normal menstrual cycle. The menstrual cycle is dated by patients from the first day of bleeding in one period to the first day of the next period. This interval averages 35 days in teenagers and 28 to 29 days in women from 20 to 40 years of age, but it then increases to 50 days in perimenopausal women. The four-tiered system that has been outlined provides a rational approach to differential diagnosis.