Steroid secretion by human oocyte-coroma-comulus complexes associated with conceptions following in vitro fertilization

Abstract

Seventy-one oocyte-corona-cumulus complexes (OCCCs) were obtained from eight women who conceived and delivered following in vitro fertilization (IVF) and eight women who were matched for the number of embryos transferred into the uterus but failed to conceive following the procedure. The steroid secretion of these OCCCs was assessed during a 24-hr culture period. Intermediate (N=35) and mature (N=36) complexes did not differ in steroid secretion, and progesterone was the major steroid secreted. OCCCs associated with a fertilized oocyte (N=59) produced significantly (P<0.02) higher levels of progesterone than those associated with nonfertilized oocytes (N=12) (515±53 vs 231±70 ngl OCCC/24 hr) but comparable levels of estradiol (9.17±1.14 vs 6.55±2.0 ng/OCCC/24 hr) and testosterone (0.34 ±0.09 vs 0.22±0.05 ng/OCCC/24 hr). Steroid production by OCCCs of oocytes which continued to cleave was not different from that of oocytes which did not cleave following fertilization, but the estradiol-to-testosterone ratio was significantly higher (31.4±3.5 vs 19.1±3.3; P<0.02) in the former group. The degree of cleavage was not related to the levels of steroid secretion. Cleaved oocytes associated with viable pregnancies (N=28) were derived from OCCCs which secreted significantly less testosterone than those which did not result in a pregnancy following transfer (N=26) (0.27±0.04 vs 0.41±0.04 ng/OCCC/24 hr). It is suggested that the steroids secreted by the corona-cumulus cells may directly affect the oocyte quality and its capacity to continue developing in the uterus.