Epidermal growth factor (EGF) in human preovulatory follicles

Concentrations of epidermal growth factor (EGF), progesterone (P4) and oestradiol (E2) were determined in follicular fluid (FF) aspirated from 69 preovulatory follicles in 15 women undergoing ovarian hyperstimulation and ovulation induction as part of IVF-ET treatment for infertility. Sixty-nine oocytes were obtained from these FF aspirates and 35 (51%) fertilized and cleaved in vitro. Pregnancy was achieved in five (33%) of the women. Concentrations of EGF in FF ranged between 0.60 and 2.42 ng/ml, corresponding to approximately 50% of the level in serum at the time of follicle aspiration. A significant linear correlation between levels of EGF in FF and in serum was demonstrated. By contrast, no significant relationships were found between intrafollicular levels of EGF and those of P4 and E2, or between EGF in FF and oocyte cleavage rate in vitro and the achievement of pregnancy after ET. It is concluded that EGF in FF of the human preovulatory follicles reflects a passive diffusion into the follicle from the circulation. Moreover, that intrafollicular EGF is not involved in the local regulation of human preovulatory follicle and oocyte maturation. These results, however, do not preclude an auto- and/or paracrine role of intrafollicular EGF in smaller human follicles.