Simultaneous portal blood absorption and intestinal mucosal catabolism of labelled fatty acids were investigated. Anaesthetized adult Wistar rats were infused intraduodenally either with 90 mumol of capric (C10:0), oleic (C18:1), linoleic (C18:2) or arachidonic (C20:4) 1-14C acids or with 30 mumol of each labelled fatty acid in addition to 30 mumol of oleic acid and 30 mumol of monopalmitin. For mixed infusates, experiments were carried out with two additional long-chain fatty acids: palmitic (C16:0) and erucic (C22:1) 1-14C acids. Radioactivity was quantified in the lipids and in the catabolic products in portal blood recovered at 5 min intervals for 1 h after infusion. At the end of the experiment, the disappearance of radioactivity from the mucosa was quantified. When labelled fatty acids were infused alone, 49% of the radiolabelled lipid disappearing from the mucosa was recovered in the blood for C10:0, but only 7.8% for C18:1, 6.4% for C18:2 and 10.6% for C20:4. With mixed infusates, 41% of the radiolabelled lipid disappearing from the mucosa was recovered in the blood for C10:0 compared with 12% for C18:1, 10.2% for C18:2, 10.5% for C20:4 and 2.7% for C16:0 and 2% for C22:1. Labelled catabolites appear with the same profiles as those of the respective fatty acids in blood. These studies confirm a minor absorption into blood of long-chain fatty acids compared to the medium-chain fatty acids and highlight differences in the catabolism of the fatty acids according to their chain length and their degree of unsaturation. The differences might be related to the differences in the fatty acid hydrosolubility and to their different affinities for the I- and L-cytosolic fatty acid binding proteins. These phenomena may be important in nutrition in relation to the availability of essential fatty acids.

This article has been cited by other articles:

				S. P. J. Dullens, R. P. Mensink, M. C. E. Bragt, A. K. Kies, and J. Plat Effects of emulsified policosanols with different chain lengths on cholesterol metabolism in heterozygous LDL receptor-deficient mice J. Lipid Res., April 1, 2008; 49(4): 790 - 796. [Abstract] [Full Text] [PDF]

				T. Porsgaard, X. Xu, J. Gottsche, and H. Mu Differences in the Intramolecular Structure of Structured Oils Do Not Affect Pancreatic Lipase Activity In Vitro or the Absorption by Rats of (n-3) Fatty Acids J. Nutr., July 1, 2005; 135(7): 1705 - 1711. [Abstract] [Full Text] [PDF]

				M.-B. Fruekilde and C.-E. Hoy Lymphatic Fat Absorption Varies among Rats Administered Dairy Products Differing in Physiochemical Properties J. Nutr., May 1, 2004; 134(5): 1110 - 1113. [Abstract] [Full Text] [PDF]

				and Carl-Erik Hoy; Structured Lipids Improve Fat Absorption in Normal and Malabsorbing Rats J. Nutr., November 1, 2000; 130(11): 2802 - 2808. [Abstract] [Full Text] [PDF]

				T. Porsgaard and C.-E. Høy Lymphatic Transport in Rats of Several Dietary Fats Differing in Fatty Acid Profile and Triacylglycerol Structure J. Nutr., June 1, 2000; 130(6): 1619 - 1624. [Abstract] [Full Text]

				P. Degrace, C. Caselli, and A. Bernard Long-Term Adaptation to High-Fat Diets Modifies the Nature and Output of Postprandial Intestinal Lymph Fatty Acid in Rats J. Nutr., February 1, 1998; 128(2): 185 - 192. [Abstract] [Full Text]