Ontogenesis and characteristics of epidermal growth factor receptors in human placenta

Epidermal growth factor promotes growth in many cell types. The role of epidermal growth factor during gestation and fetal development is unknown. This study investigates the presence and binding characteristics of epidermal growth factor receptors in placentas throughout gestation. Cell membrane preparations were obtained from first-, second-, and third-trimester placentas and hydatidiform moles. Specific epidermal growth factor receptors were observed as early as 6 weeks of gestation. Throughout gestation, Scatchard analysis of epidermal growth factor binding was curvilinear, and dissociation studies were consistent with site-to-site interaction with negative cooperativity. Affinity constants at high (Ke = 9.9 +/- 0.79 X 10(9) L/mol) and low (Kf = 3.0 +/- 0.25 X 10(9) L/mol) receptor occupancy were unchanged throughout normal gestation. However, the number of receptors per milligram of protein significantly increased with advancing normal gestation (correlation coefficient, r = 0.81). In hydatidiform moles, the number of receptors was reduced when compared to that of normal tissue of similar gestational age. Our study provides a quantitative basis for further evaluation of epidermal growth factor as a possible factor in embryogenesis and fetal development.