Effect of oral phytohaemagglutinin intake on cell adaptation in the epithelium of the small intestine of the rat.

The effect of phytohaemagglutinin (PHA) on the adaptation of the proximal jejunal epithelium and on the distal ileal epithelium was studied in rats. The group receiving PHA gained less weight than controls, and the enterocyte population of their jejunal villi, as well as the morphokinetic parameters (length, population, crypt cell production per crypt) of their jejunal and ileal crypts were higher than those of the controls. The proximal lesion caused by PHA (reduction of villus cell populations) stimulates hyperplasia of the crypt-villus unit of the ileal epithelium with the development of adaptation from afar. These adaptations occurred in animals that ingested PHA even in the presence of severe malnutrition.