Sources of Cholesterol in the Intestinal Lymph in Rats Fed a Cholesterol-Free Diet 1

Summary The intestinal lymphatics were successfully cannulated in 10 adult male Sprague-Dawley rats fed a cholesterol-free diet; 40-60 days prior to cannulation, these animals received an intracardiac injection of a single dose of cholesterol-4-14C. The intestinal lymph was collected over a period of 6 hr. The animals were then sacrificed. The cholesterol and its specific activity in plasma, liver, and mucosa of various segments of gastrointestinal tract were measured and the sources of cholesterol in the intestinal lymph were determined by comparison of their relative specific activities. Of the total cholesterol in the intestinal lymph, 0.491 μM/hr, 81.5% or 0.398 μM/hr was derived from exchangeable cholesterol in the intestine considered to be the same pool as the plasma cholesterol, and 18.5% or 0.088 μM/hr was synthesized de novo in the intestinal mucosa. The latter accounted for 22% of the daily turnover of the plasma cholesterol. The authors express their appreciation to Miss Belma Mikkelson and Miss Janice Drummond for their technical assistance.