Comparative intestinal and colonic absorption of [4-14C] cholesterol in the rat.

[4(-14)C] Cholesterol was administered as an aqueous emulsion with triolein and dry non-fat milk either directly into the upper duodenum or into the ileocaecal junction of lymph duct cannulated rats. Lymph flow rates were similar in the two groups of animals. Whereas ca. 53% of the administered tracer dose of cholesterol was absorbed when introduced into the upper small intestine, only 0.06% appeared in lymph when administered into the caecum. Furthermore, less than 0.01% of the administered isotope was detected in urine and blood. The data demonstrate that the large intestine does not contribute significantly to the absorption of exogenous cholesterol in the rat.