Synergetic effects of epidermal growth factor and gonadotropins on the cytoplasmic maturation of pig oocytes in a serum-free medium.
Cumulus-enclosed or cumulus-free pig oocytes were cultured for 48 h in a serum-free maturation medium, TCM-199B containing 1 mg/ml polyvinylalcohol, supplemented with gonadotropins (PMSG + hCG) and/ or epidermal growth factor (EGF), and inseminated with frozen-thawed ejaculated spermatozoa. Fourteen hours after insemination, the ability of oocytes to form male pronucleus (MPN) was examined. EGF significantly increased the ability of cumulus-enclosed oocytes to form MPN irrespective of the concentrations (1-100 ng/ml) tested. Gonadotropins had a greater effect than EGF on MPN formation in cumulus-enclosed oocytes, and a synergetic effect was observed when EGF and gonadotropins were added together. However, neither EGF nor gonadotropins exhibited a stimulatory effect on MPN formation in cumulus-free oocytes. These results indicate that the role(s) of both EGF and gonadotropins in stimulating cytoplasmic maturation of pig oocytes is mediated by cumulus.
Wang
W
W
Okayama University, Japan.
Niwa
K
K
D000818:Animals; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D046508:Culture Techniques / Q000379:methods; D003593:Cytoplasm / Q000187:drug effects*; D004357:Drug Synergism; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005260:Female; D005307:Fertilization in Vitro; D006062:Gonadotropins / Q000494:pharmacology*; D008297:Male; D009865:Oocytes / Q000187:drug effects*; D013552:Swine
D016895:Culture Media, Serum-Free; D006062:Gonadotropins; D004815:Epidermal Growth Factor