出版社：American Society for Biochemistry and Molecular Biology
摘要：We have previously described a novel pathway for the metabolism of HDL subfractions in which small [2 apolipoprotein (apoA-I) molecules per particle] HDL particles are converted in a unidirectional manner outside the plasma compartment to medium (3 apoA-I molecules per particle) or large (4 apoA-I molecules per particle) HDL particles, which are subsequently removed from the circulation by the liver (Colvin et al. 1999. J. Lipid Res. 40: 1782–1792; Huggins et al. 2000. J. Lipid Res. 41: 384–394). The purpose of the present study was to determine whether the reduction in concentration of medium HDL in African green monkeys consuming n-3 polyunsaturated versus saturated fat diets resulted from decreased in vivo production or increased catabolism. Tracer small LpA-I (HDL containing only apoA-I) were isolated, without ultracentrifugation, by gel filtration and immunoaffinity chromatography and radiolabeled. After injection, the specific activity of apoA-I in small, medium, and large HDL was determined, and the kinetic data were analyzed using our previously published multicompartmental model for HDL subfraction metabolism. We found a significant reduction of apoA-I concentration in medium HDL in the animals fed n-3 polyunsaturated fat (31.2 ± 0.7 mg/dl) compared with animals fed saturated fat (85.4 ± 11.9 mg/dl; P = 0.002). The production rates of apoA-I in small, medium, and large HDL were similar in both diet groups; however, there was a significant increase in the fractional catabolic rate of apoA-I in medium HDL in the animals fed n-3 polyunsaturated fat (2.188 ± 0.501 pools/day) compared with animals fed saturated fat (0.714 ± 0.191 pools/day; P = 0.02). We conclude that n-3 polyunsaturated fat reduces HDL cholesterol concentration by increasing the fractional catabolic rate of medium-sized HDL particles in African green monkeys. —Huggins, K. W., P. L. Colvin, E. R. Burleson, K. Kelley, J. K. Sawyer, P. H. R. Barrett, L. L. Rudel, and J. S. Parks. Dietary n-3 polyunsaturated fat increases the fractional catabolic rate of medium-sized HDL particles in African green monkeys. J. Lipid Res. 2001. 42: 1457–1466.
关键词：fish oil ; LpA-I ; apolipoprotein A-I ; PUFA ; non-human primates ; saturated fat ; in vivo catabolism
