[Electron microscopic study of in vitro differentiation of the small intestinal endoderm in young bird embryo in the presence or absence of mesenchyme].

Electron microscopical studies demonstrated that the small intestinal endoderm of young avian embryos cultures in vitro in the presence or absence of mesenchyme can differentiate into an absorptive epithelium with the brush border, and that, in the absence of mesenchyme the brush border develops much earlier than in the presence of mesenchyme, but goblet cells do not appear and morphogenesis of villi does not occur. These results show that the intestinal mesenchyme controls the endodermal differentiation, though the undifferentiated endoderm possesses self-differentiation potency.