Steroid secretion by the human egg-corona-cumulus complex in culture

Forty-five oocyte-corona-cumulus complexes ( OCCC ) were obtained from follicles of 13 women undergoing fertilization in vitro. Follicular growth was induced with human menopausal gonadotropin, and follicular aspiration was performed 36 h after an ovulatory injection of hCG. The maturation of these complexes was evaluated by the extent of cumulus mucification and corona cell dispersal. Three main morphological types were characterized: immature OCCCs (6), with a tight and compact corona-cumulus mass surrounding the oocyte; intermediate OCCCs (26), with a dispersed cumulus but only partly dispersed corona layer; and mature complexes (13) with complete dispersal of both cellular components. During a 24-h culture, progesterone secretion by intermediate and mature OCCCs was 30-fold higher (mean +/- SEM, 652 +/- 87 ng/ OCCC X 24 h) than immature OCCCs (19.6 +/- 3.5 ng/ OCCC X 24 h), while estradiol secretion was twice as high (3.8 +/- 1.1 vs. 1.2 +/- 0.6 ng/ OCCC X 24 h). Testosterone secretion was similar in all three types of OCCCs cultured (0.30 ng/24 h). It is suggested that the steroids produced by the OCCC may contribute to the local milieu of the fallopian tube.