Follicular fluid inhibin activity and steroid levels in ovarian tissue obtained at autopsy from human infants from 18 to 200 days of age.

The ovaries of 25 human infants from 18 to 200 days of age were obtained at autopsy, and their follicular fluid was subjected to measurement of inhibin activity, estrogen, progesterone, androstenedione, and testosterone. Significant inhibin activity was present in all samples of follicular fluid (charcoal-treated) (138 +/- 19 U/10 microliter follicular fluid; 10,545 +/- 2758 U/ovary). There was a tendency for greater inhibin activity, follicular volume, and estrogen in infants from 18 to 59 days than in older infants. There was a significant positive correlation between follicular fluid volume, estrogen, and androstenedione, compared with follicular fluid inhibin content per ovary. It is possible that elevated serum follicle-stimulating hormone and luteinizing hormone observed early in life stimulates follicle growth, inhibin, and estrogen production. As a result of elevated inhibin and estrogen, the gonadotropins may be inhibited, which may cause a decline in follicular activity after 4 to 6 months.