Proliferation of guinea-pig uterine epithelial cells in serum-free culture conditions: Effect of 17β-estradiol, epidermal growth factor and insulin

Abstract

The effects of 17β-estradiol (E 2), epidermal growth factor (EGF) and insulin, alone or in association on guinea-pig uterine epithelial cell proliferation were examined in serum-free culture conditions. Primary cultures of epithelial cells were made quiescent by serum depletion, then incubated in a chemically defined medium. In this medium, insulin increased DNA synthesis but not in a dose-dependent manner for concentrations ranging from 0.2 to 10 μg/ml. A significant effect of EGF was found only for the highest concentration tested (100 ng/ml). E 2 alone or in the presence of insulin (1 μg/ml) had no effect whatsoever on the concentration tested (10 −10−10 −5 M). Insulin (10 μg/ml) plus EGF (100 ng/ml) exerted on DNA synthesis and cell proliferation a significant additive effect which was identical to the growth stimulation induced by 10% fetal calf serum. The effects of insulin plus EGF were not modified by the addition of E 2. These findings suggest that E 2 is not directly mitogenic for uterine epithelial cells in defined culture conditions and that the mitogenic response to optimal concentration of insulin plus EGF is independent of E 2.