Role of capillary endothelium in the clearance of chylomicrons. A model for lipid transport from blood by lateral diffusion in cell membranes.
Year: 1976
Type: review
Abstract: TABLE 1 Composition of Chylomicrons (Rat) Component Core Triglyceridc Cholesteryl ester Surface film Phospholipid (lecithin) Cholesterol Protein Triglyceride Diglyceride Monoglyceride Fatty acids Amount %of total 92.40 0.08 4.60 0.24 0.60 0.10 1.80 0.04 0.14 %of surface film --61.23.2 8.0 1.3 23.9 0.5 1.9 Bated on analyse* of chylomicron isolated from thoracic duct lymph of raU tube-fed com oil. 1 -•• "• " Values are expressed as percentage of weight.apoC-II, 32 and its action on triglyceride is suppressed in hypertonic NaCl s o l u t i o n ." ' 4 "Recent studies have shown that lipoprotein lipase has positional specificity for the primary ester bonds of glycerides."- 40The enzyme readily hydrolyzes triglyceride and l,2(2,3)-diglyceride to 2-monoglyceride and FFA, and 1(3)monoglyceride to glycerol and FFA, but has no effect on 2-monoglyceride.Thus, complete hydrolysis of triglyceride to glycerol and FFA by lipoprotein lipase requires isomerization of 2-monoglyceride to l(3)-monoglyceride.Lipoprotein lipase also hydrolyzes the primary acyl ester bond of lecithin to form 2-acyl lysolecithin. 41This isomer differs from that formed by LCAT" and phospholipase A,, 42 1-acyl lysolecithin.The fate of 2-acyl lysolecithin has not been studied. Uptake of Chylomicron Triglyceride by Extrahepatic TissuesTriglyceride fatty acids in chylomicrons are rapidly cleared from the blood when injected intravenously.The rate of clearance and fate of the fatty acids, however, depends on the nutritional and physiological state of the animal. 4'" 4 * In fed rats, about 32% of the fatty acids removed from blood in 10 minutes were found in adipose tissue, 32% in skeletal muscle, 18% in liver, and about 2% each in heart, kidney. TABLE 2 Protein Composition of Chylomicron-Very Low Density Lipoprotein (VLDL) Fraction Isolated from Rat Intestinal LymphApoprotein A-I A-II B C-I C-II C-I 11 % of total protein 30 7.5 35 2.5 7.5 17.5
Source: Circulation Research
Authors: R O Scow, E J Blanchette-Mackie, L C Smith
Language: English
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2136371576