Effect of ethanol on transport from rat intestine during high and low rates of oleate absorption.

Long-chain fatty acids (LCFA) are transported predominantly in the intestinal lymph when rates of LCFA absorption are high, and oral ethanol has been shown to enhance this lymphatic transport. A greater proportion of absorbed LCFA is transported via portal blood when rates of LCFA absorption are low. We tested the hypothesis in unanesthetized lymph-fistula rats that ethanol might also enhance the mucosal absorption and lymphatic transport of oleic acid when oleate absorption rates were low. The results did not support this hypothesis. Ethanol enhanced oleate absorption and transport from the intestine when 360 mumol, but not when 8 mumol of [14C] oleate was infused intraduodenally over 4 hr. There were major differences in intestinal mucosal metabolism of high and low loads of oleic acid. After the high load, the proportion of intestinal [14C] phospholipid to [14C] neutral lipid was 8:92. This ratio changed to 37:63, and the percentage of neutral 14C as triglyceride decreased from 87 to 68% when the low load of oleate was infused. We suggest that a portion of absorbed LCFA is incorporated into phospholipid and transported as high-density lipoproteins in portal blood. This portal pathway for LCFA was uninfluenced by ethanol in the present experiments.