Comparison of sensitivities of uterine cells in their proliferation responding to epidermal growth factor and estrogen between neonatal and postneonatal mice.

摘要

The uteri of mice up to 20 days after birth show estrogen-independent growth, although their growth is accelerated by estrogen, while the growth of the uteri of mice after 20 days completely depends on estrogen. In the present study, we compared the sensitivities of uterine cells in their proliferation responding to epidermal growth factor (EGF) and diethylstilbestrol (DES) between 5-day-old and 25-day-old ovariectomized mice. A single subcutaneous injection of EGF at doses of 0.25 and over 0.25 microgram/g body weight (BW) increased 3H-thymidine uptake by the whole uterus dose-dependently in both 25-day-old and 5-day-old mice, and a maximal increase in the 3H-thymidine uptake was attained at a dose of 1 microgram/g BW of EGF in both mice. A single subcutaneous injection of DES at 0.001 and over 0.001 microgram/g BW increased 3H-thymidine uptake by the whole uterus dose-dependently in both 25-day-old and 5-day-old mice, and a maximal increase was attained at 0.004 microgram/g BW of DES in both mice. EGF and DES increased labeling indices of both the epithelium and stroma in both 25-day-old and 5-day-old mice. The present results suggest that sensitivities of uterine cells of neonatal mice in their proliferation responding to EGF and DES are similar to those of postneonatal mice.