出版社：American Society for Biochemistry and Molecular Biology
摘要：Adipose tissue was shown to contain 0.6–1.6 mg of cholesterol per gram wet weight. When expressed per unit of protein or organ mass, fat tissue contains more cholesterol than most other organs or membranes. The cholesterol content of fat tissue increased with the age and weight of the rat. Over 95% of adipose tissue sterols was cholesterol, and most of it was free. In young (150–165 g) rats two-thirds of fat tissue cholesterol was in collagenase-derived adipocytes while in older rats (450–480 g) 90% of fat tissue cholesterol was in adipocytes and the remainder was in stromal–vascular elements. Age-related differences in subcellular cholesterol distribution were also observed. The cholesterol/phospholipid molar ratios of purified plasma membrane fractions from small and large fat cells were identical (0.22–0.25), thus resembling muscle and liver membranes. 7.5 days after intravenous administration of [4-14C]cholesterol the specific activity of adipose cholesterol exceeded that of plasma cholesterol. At 28 days the specific activity of adipose and muscle cholesterol exceeded that of plasma three- to fivefold. The t½ disappearance of adipose tissue cholesterol was approximately 27 days, which is consistent with its function as a slowly turning over storage pool. Thus, fat tissue is a major cholesterol storage organ. This may well account for the marked expansion of the slowly exchangeable cholesterol pool (pool B) observed in obesity.
