高HDL血症モデル動物の作成に関する研究

Abstract

This study was undertaken to determine the effect of hyperinsulinemia and/or sucrose-feeding on lipoprotein metabolism in rats. Sixty male Wistar rats with a mean body weight of 350g were used in this study. They received gradually increasing dose of NPH insulin subcutaneously for 11 days. There were four groups of rats; sucroseinsulin (SI), sucrose-control (SC), chow-insulin (CI) and chow-control (CC). SI and SC groups were given 5% sucrose solution as drinking water (to avoid hypoglycemia after insulin injection). The final insulin dose was 6U and 4U in SI and CI group, respectively. At noon time (approximately 17 hr after insulin injection) of day 11, blood was obtained with EDTA from the abdominal aorta of 3hr fasted rats anesthetized with sodium pentobarbital. Each separated plasma pool was prepared from two equal volume of rat plasma. Lipoprotein fractionation was done by preparative ultracentrifugation. Each floating fraction was obtained by slicing and served for triglyceride and cholesterol assay.There were no significant differences in plasma insulin and glucose levels between each experimental group and CC group. High density lipoprotein (HDL)-cholesterol concentration in SI group was the highest of all 4 groups and significantly differed from that of CC group. On the other hand, low density lipoprotein (LDL)-cholesterol in SI group was the lowest of all groups. CI group showed no remarkable differences in triglyceride and cholesterol concentration in each lipoprotein fraction compared to those of CC group.It was suggested from the present data that the combination of hyperinsulinemia and sucrosefeeding raises HDL-cholesterol and suppresses LDL-cholesterol level in rats. Such a kind of hyperinsulinemic rats can be a good model for experimental hyper-α-lipoproteinemia.