Effect of activin on cell growth in primary cultures of guinea pig gastric epithelial cells.

Abstract

The effect of activin on differentiated cells is known to be different from that on undifferentiated cells. Cultured gastric epithelial cells in complete serum-free conditions grew into matured mucous cells after treatment with epidermal growth factor (EGF). To elucidate the effect of activin on the growth of differentiated and undifferentiated gastric mucosal cells. Cultured guinea pig gastric epithelial cells were prepared using the method of Ogihara et al. Synthesis of activin was analysed by Western blot using monoclonal anti-activin A antibody. Cell proliferation was assessed by counting the number of cells. Mucin production was assessed by histochemical study using periodic acid-Schiff (PAS) reaction. Western blot analysis indicated that activin was synthesized in cultured guinea pig gastric mucosal cells. One hundred nanomolar EGF induced a 3-fold increase in cell count and the appearance of PAS-positive granules. Five nanograms activin per millilitre without EGF stimulated proliferation of the cells that showed almost negative PAS staining. When activin was added after treatment with 100 nM EGF for 24 h, cell proliferation induced by EGF was inhibited by activin at concentrations higher than 5 ng/mL. These results suggest that activin stimulates proliferation of undifferentiated cells and inhibits growth of differentiated cells.