Abstract

A growth stimulating activity has been recently identified in the rat proximal intestine during the transient stages of adaptation after small bowel resection. This study shows that the growth stimulating activity is associated with all the cells of the crypt-villus axis. At the same time the thymidine kinase activity is detectable in all the cells implying a more extensive proliferative zone during the transient stages of adaptation. The presence of the growth stimulating activity along with the more extensive proliferative zone suggests that the activity modulates the proliferation capacity of intestinal epithelial cells.