Effect of Human Cord Serum on the Hormone Production by Mouse Oocyte Cumulus Complexes in vitro

Lee, Yu Il; Park, Hyun Jeong; Kwon, Young Suk

Abstract

In our previous study, it was shown that human cord serum stimulated cumulus expansionin vitro by cumuli oophori isolated from mice primed with pregnant mare serum gonadotropin(PMSG), and suggested that there were some gonadotropin-like components stimulating cumulusexpansion in human cord serum. In this paper we assess whether there are gonadotropinstimulating cumulus expansion in human cord serum and sex steroid hormone production fromoocyte cumulus complexes(OCCs). The contents of follicle stimulating hormone(FSH) andluteinizing hormone(LH) were measured in human cord serum: follicle stimulating hormone levelwas basal, but luteinizing hormone was as high as 142.4 mIU/ml even in inactivated serum.After short term culture(4hr), with or without OCCs, medium containing 0.4% bovine serumalbumin(BSA) as control or 10% human cord serum(HCS) was collected and analyzed for itscontent of estradiol, progesterone and testosterone. Little or no sex steroid contents were detectedin any control media with or without OCCs. In contrast, a moderate or small amount ofsex steroid contents was detected in culture medium containing cord serum. OCCs secretedminute but not significant amounts of estradiol, progesterone, and testosterone when culturedin media containing cord serum. After 4, 8, and 22hr culture with OCCs, similar patterns ofcumulus expansion were observed in media containing cord serum, human chorionic gonadotropin(HCG) instead of luteinizing hormone(LH), and HCS plus HCG. However, no cumulus expansionwas observed in any control media.It is suggested that luteinizing hormone in human cord serum induces cumulus expansionand affects the secretion of sex steroid hormones by OCCs during culture.