BINDING OF EPIDERMAL GROWTH-FACTOR AND TRANSFORMING GROWTH-FACTOR-ALPHA IN MAMMALIAN PREIMPLANTATION EMBRYOS

Preimplantation embryos of the pig (Days 11 to 15), cow (Days 14 to 16 ), sheep (Day 14) and pony (Day 16) bind epidermal growth factor (EGF) specifically Binding was not detected in embryos of the rabbit at Day 5 or 6 or the hamster at Day 3. Transforming growth factor-alpha disp laced [I-125] EGF in pig, cow and pony embryos almost as much as unlab eled EGF. The binding affinities of EGF ranged from 12 to 233 pM in pi g and cow embryos. The range of species and binding features indicate that the EGF family may play a significant role in mammalian preimplan tation development.