Relationship of epithelial growth to mitotic rate in mouse embryonic lung developing <i>in vitro</i>

Abstract

ABSTRACT The rate of cell division was studied as a function of over-all growth of the epithelial tree of the 11-day mouse embryonic lung developing in vitro, under conditions of: (1) normal growth in vitro of intact rudiments; (2) mass reduction; (3) increase of the relative amount of mesenchyme. The over-all rate of epithelial growth under experimental situations (2) and (3) is significantly higher than that of intact rudiments. The epithelial cell proliferation rate is highly correlated with the over-all size of epithelial growth in all cases. It was concluded that the over-all growth and budding activity of the epithelial tree depends on cell division. Reduction in mass and an increased amount of mesenchyme increase the rate of epithelial growth by stimulating the mitotic activity of the epithelial cells.