The association between granulosa cell aromatase activity and oocyte-corona-cumulus-complex maturity from individual human follicles

The steroidogenic capability of granulosa cells isolated from 12 preovulatory human follicles was correlated with the stage of maturation of the corresponding oocyte-coronacumulus-complex (OCCC). Individual follicles from human menopausal gonadotropin (hMG) stimulated cycles were aspirated 36 h after administration of hCG. Granulosa cells were cultured for 150 min and corresponding OCCC were evaluated for maturity before fertilization with human sperm. Granulosa cell aromatase activity was measured using 1β-³H-testosterone as substrate by quantitating the amount of ³H₂O produced. Progesterone production by the granulosa cells was measured as was follicular fluid levels of combined hCG and LH activity and FSH and PRL. Follicular fluid concentrations of combined hCG plus LH activity decreased somewhat while FSH levels increased as OCCC matured. PRL levels did not vary. Granulosa cell progesterone production did not change with maturity of OCCC. However, aromatase activity decreased as OCCC matured with levels from granulosa cells with immature OCCC vs. intermediate and mature OCCC of 260 ± 148 us. 129 ± 53 (SE) pg E₂/10⁶ cells, respectively (P < 0.07). Although granulosa cells responded variably to hMG stimulation from individual to individual, and the response was not predictable from peripheral serum estradiol levels, follicles isolated from the same patient had a definite diminution in aromatase activity with OCCC maturation. From these preliminary results, aromatase activity in immediately preovulatory granulosa cells declined as OCCC matured in hMG/hCG stimulated cycles.