HYPERTROPHY OF SMALL INTESTINE AFTER ITS PARTIAL RESECTION IN RAT - ULTRASTRUCTURE OF INTESTINAL EPITHELIUM

The authors investigated the ultrastructure of small intestinal epithelium in the rat, 3 weeks after resection of the proximal half of the small intestine. They sought to determine: (1) whether the compensatory hypertrophy of the mucosa of the residual small intestine results in changes in the microvilli, in addition to prolongation of the villi; and, (2) whether it is possible to provide evidence of less complete morphologic differentiation in the more rapidly migrating enterocytes. The epithelium on the surface of villi in animals after resection does not differ ultrastructurally from controls and is formed by completely differentiated cellular elements. It is apparent that the compensatory enlargement of the intestinal absorption surface is a result of the hypertrophy of the mucosal villi, and not of changes in the microvilli. © 1969 Hoeber Medical Division • Harper & Row, Publishers, Incorporated.