アスコルビン酸の血清リポ蛋白に及ぼす影響

Abstract

Effects of hypovitamin C on chemical composition in serum lipoprotein and contents of lipids in the aorta were studied.Guinea pigs were made hypovitamin C by scorbutogenic diet (group 1) or cholesterol and coconut oil added scortogenic diet (group 3) for two weeks. The controls for the experimental animals were fed on a similar diet and supplemented with 25mg of vitamin C daily (group 2 and 4). Lipoproteins were isolated with ultracentrifuge according to Hatch's method. Lipids contents in isolated lipoprotein fractions were estimated with conventional methods described elsewhere. Protein contents in the lipoproteins were estimated by Hartree's method. Amounts of chylmicron, very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL) classes were significantly elevated as compared with the control, group 2. Concentration of triglyceride in VLDL, cholesterol ester in LDL were also increased in group 1. Increased amount of LDL, lower cholesterol and higher apoprotein levels in HDL of group 3 were observed as compared with the control, group 4. Eight bands of apoprotein were separated with triton containing polyacrylamide gel disc electorophoresis. The first band of group 1 was stained strongly dark and the others were faint as compared with those of group 2. First band of group 3 was also stained very dark as group 1. The staining intensity of other bands of group 3 were decreased relatively as compared with those of the control, group 4.Total cholesterol, phospholipid and triglyceride tontents in the aorta of group 1 were increased significantly than those of group 2. There was a tendency of elevation of total cholesterol and phospholipid contents in the aorta of group 3, but no statistical difference were found against group 4.From these results, impaired clearance of chylomiron remnants and accumulation of cholesterol ester rich chylomicron and LDL by hypovitamin C were assumed. Altered apoprotein constituents in HDL also may concern with changes of lipoprotein metabolism in hypovitamin C. Thus, hypovitamin C is pathogenic to atherosclerosis not only by decreased integrity of the vascular wall as previously reported, but also by altered lipid metabolism as observed in the present study.