Estrogens stimulate proliferation and differentiation of uterine epithelial cells in vivo. Mitogenic action of estrogens may be mediated by growth factors such as insulin-like growth factor-I (IGF-I). This study was designed to determine whether IGF-I and insulin affect proliferation of uterine epithelial cells obtained from 3- to 4-week-old immature female mice in a serum-free culture system. The epithelial cell number on Day 5 in culture was significantly increased by adding IGF-I (10 and 100 ng/ml) or insulin (100 and 1000 ng/ml) to the culture media, indicating that IGF-I is more effective than insulin in inducing the epithelial growth. The epithelial DNA synthesis was significantly stimulated by IGF-I (1 and 10 ng/ml), suggesting that both the epithelial proliferation and their detachment from substratum are stimulated by 1 ng/ml of IGF-I, but that the former is more accelerated than the latter by 10 ng/ml of IGF-I. These results demonstrate that both IGF-I and insulin directly stimulate the growth of uterine epithelial cells, and suggest that insulin may act via IGF-I receptors. IGF- I immunoreactivity was detected in the cytoplasm of the cultured cells, indicating that the cells synthesize IGF-I. Estradiol-17β (E2) at lower concentrations (0.001-0.1 nM) tended to increase the number of epithelial cells, while E2 at higher concentrations (1 to 100 nM) did not affect it. It is highly probable that IGF-I produced in endometrial cells induces their proliferation by an autocrine or paracrine mechanism.
|Number of pages||6|
|Journal||Proceedings of the Society for Experimental Biology and Medicine|
|Publication status||Published - Sep 1 1997|
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)