CONCENTRATION OF OESTROGENS AND ANDROGENS IN HUMAN OVARIAN VENOUS PLASMA AND FOLLICULAR FLUID THROUGHOUT THE MENSTRUAL CYCLE

TLDR

The study quantified androstenedione, testosterone, oestrone, and oestradiol‑17β concentrations in peripheral and ovarian venous blood and follicular fluid from women at multiple menstrual‑cycle stages. During the cycle, estradiol remained stable in small follicles and largely unchanged in large follicles except for a mid‑to‑late follicular peak (~1500 ng/ml), androstenedione was lowest in large preovulatory follicles at midcycle despite increased ovarian‑vein secretion, testosterone stayed constant in large follicles but peaked in small follicles at midcycle, and the concurrent rise of testosterone and androstenedione in peripheral plasma is attributed to preovulatory follicle secretion, with low follicular androstenedione explained by granulosa‑cell aromatization.

Abstract

The concentrations of androstenedione, testosterone, oestrone and oestradiol-17beta were measured in peripheral and ovarian venous blood and follicular fluid of women at various stages of the menstrual cycle. The concentration of oestradiol was similar in small follicles (diameter less than 8 mm) at all stages of the menstrual cycle and in large follicles (diameter greater than or equal to 8 mm) except during the mid- and late follicular phase when the concentration reached a peak (approximately 1500 ng/ml). The concentration of androstenedione was lowest in large preovulatory follicles at midcycle at a time when the secretion into the ovarian vein was markedly increased. The concentration of testosterone in large follicles (greater than or equal to 8 mm) was unchanged during the follicular phase whereas in small follicles there was a peak at mid-cycle. The rise in the concentration of testosterone and androstenedione at mid-cycle in peripheral plasma may be due to increased secretion by the preovulatory follicle into the ovarian vein. It is suggested that the relatively low concentration of androstenedione in follicular fluid of the preovulatory follicle arises from increased aromatization by granulosa cells in the course of oestrogen synthesis.