Rat liver epidermal growth factor receptors in intrauterine growth retarded and heavy-for-date fetuses.

We recently reported that epidermal growth factor (EGF) levels in the first urine to be voided by intrauterine growth retardation (IUGR) and heavy-for-dates (HFD) infants were lower than control infants (8). In this study, we analyzed EGF receptors to reveal the mechanisms controlling EGF levels. EGF binding to fetal rat liver increased markedly from day 19-21 of gestation. Fetal rats were divided into IUGR, control and HFD groups. EGF binding to the liver in each group was as follows, IUGR; 380 +/- 57 fmol/mg protein, control; 258 +/- 47, and HFD; 545 +/- 112. The binding to IUGR and HFD rat liver was significantly greater than in the control group (p < 0.05). These data suggest that IUGR rats compensate for a lack of EGF by increased receptor expression and that HFD rats consume more EGF and have decreased urinary EGF excretion. These data also suggest that EGF is closely related to fetal growth and may play some important roles in fetal growth.