Intestinal absorption of carbohydrates in man

Abstract

The metabolic fate of 1 g of 'H/'4C-labeled dili-noleoglycerophosphocholine was studied in five patients after oral administration. The 'H label was in choline and I4C was in the two linoleic acid residues. More than 90% of both isotopes was absorbed from the intestine. Seventy to 90% of the 'H radioactivity in blood was linked to phosphatidylcholine (PC) whereas I4C was associated with both PC and nonpolar lipids. At peak activity, the 'H/14C ratio of plasma PC was twice that of oral PC; this suggests that most oral PC was hydrolyzed to lysolecithin before absorption. The mean maximum concentration in total blood volume was 20% of the administered dose for 'H and 28% for I4C. Examination of lipoproteins revealed that the specific activity of PC in high density lipoprotein (HDL) was 2 to 6 times higher than in apoB-containing lipoproteins, and 2 to 20 times than that of red blood cells or total blood. Thus, absorbed PC seemingly was incorporated preferentially into the HDL fraction of plasma.-Zierenberg, O., and S. M. Grundy. Intestinal absorption of polyenephosphatidylcholine in man. J. Lipid Res. 1982. 23: 1 136-1 142.