INTESTINAL-CELL PROLIFERATION IS INFLUENCED BY INTAKES OF PROTEIN ANDENERGY, AFLATOXIN, AND WHOLE-BODY RADIATION

Intestinal epithelial cell proliferation in young male F344 rats was m easured in response to dietary protein content (5%, 10%, and 20% casei n diets), energy restriction (energy intake was 60% of ad libitum ener gy intakes of animals consuming the 20% casein diet), total diet restr iction (dietary intake was 60% of the ad libitum intake of 20% casein diet group), aflatoxin administration, and whole body irradiation. Cel lular proliferation was measured in sections of jejunum, ileum, proxim al colon, and distal colon with the [H-3]thymidine technique. Restrict ing energy or total diet intakes by 40% from ad libitum levels reduced proliferation in epithelial cells throughout the intestine. In compar ison to the 5% casein diet, the 20% casein diet resulted in modestly l ower cellular proliferation in all intestinal segments. Radiation indu ced a decrease in cellular proliferation in the jejunum and ileum; thi s decrease was prevented by a 20% casein diet. Pretreatment with aflat oxin B-1 decreased intestinal cell proliferation throughout the intest ine, and this decrease was not influenced by the protein content of th e diet.