Effects of an inhibitor isolated from human small intestine on organ culture of intestinal mucosa.

Endogenous mitotic inhibitors have been implicated as controlling mechanisms of intestinal epithelium proliferation. We previously reported the purification of an inhibitor of intestinal epithelial cells in culture isolated from a villous extract of human jejunum. This article describes the biologic effects of this inhibitor on organ cultures of rabbit intestinal mucosa. Our results reveal that (1) this factor is not cytotoxic; (2) it inhibits intestinal epithelial cell proliferation in a dose-dependent and reversible manner; (3) it does not appear to be species-specific; (4) it is specific to the digestive tract, and more particularly to the small intestine.