Abstract
To evaluate the effects of epidermal growth factor (EGF) on placental amino acids uptake, transport activities for L-proline, L-leucine, and L-alanine were kinetically examined in placental microvillous vesicles(PMV) obtained from pregnant rats administered with EGF(100 and 200 μg/kg/day) from day 18 to 21 of pregnancy. The Vmax of Na+-dependent proline uptake remarkably increased with a dose-dependent manner of EGF, while Km did not change. In contrast, Vmax and Km values of Na+-dependent and -independent alanine, and Na+-independent leucine uptake were not affected. These results suggested that EGF enhanced proline transport activity in placental microvillous membranes, resulting in an increase of proline concentration in the fetal blood. The selective up-regulation of proline uptake was considered to contribute to fetal growth by EGF.
