Demonstration of a gradient in inhibin activity, estrogen, progesterone, and delta 4-androstenedione in follicular fluid, ovarian vein blood, and peripheral blood of normal women.

Ovarian vein serum from 3 subjects during the late follicular phase of the menstrual cycle had detectable inhibin activity, whereas ovarian vein serum of 12 other subjects during the early follicular phase and luteal phase had no detectable inhibin activity in a rat anterior pituitary cell culture assay. Subjects having detectable inhibin activity (102 +/- 47 U/100 microliters) had 1257 +/- 582 U/100 microliters inhibin activity in FF, whereas subjects having no detectable inhibin activity had FF levels of 711 +/- 203 U/100 microliters of inhibin activity. Estrogen levels of FF and ovarian vein serum of the group having detectable inhibin activity in ovarian vein serum were 282 +/- 239 ng/ml and 4.8 +/- 1.77 ng/ml, respectively. The estrogen content of FF and ovarian vein blood of the group having nondetectable inhibin activity in ovarian vein blood was 127 +/0 45 ng/ml and 3.03 +/- 0.6 ng/ml, respectively.