Cha M C, Jones P J
School of Dietetics and Human Nutrition, Macdonald Campus of McGill University, Ste Anne de Bellevue P.Q., Canada.
J Lipid Res. 1998 Aug;39(8):1655-60.
To investigate whether dietary fat source and energy restriction interactively influence plasma leptin levels and its association of leptin with insulin action, rats were fed diets containing either fish, safflower oil, or beef tallow (20% wt/wt) for 10 weeks. Groups of rats consumed each diet ad libitum or at 85% or 70% of ad libitum energy intake in a design that held fat intake constant. Graded levels of energy restriction caused body weight to decrease (P < 0.001) differently according to the dietary fat provided. Plasma leptin concentrations were 60% higher (P < 0.05) in the groups fed fish oil and safflower oil ad libitum compared with those in the beef tallow group, despite smaller perirenal fat mass and fat cell size in the fish oil-fed animals. Energy restriction resulted in a 62% decrease (P < 0.05) in leptin levels in fish oil- and safflower oil-fed rats, whereas no changes were observed in beef tallow-fed animals. Plasma insulin levels were lower (P < 0.05) in the fish oil group fed ad libitum compared with those in the two other diet groups. These data demonstrate a hyperleptinemic effect in animals consuming diets rich in polyunsaturated fatty acid, which can be normalized to the level of saturated fat consumption by mild energy restriction. Thus, dietary fatty acid composition, independent of adipose tissue mass, is an important determinant of circulating leptin level in diet-induced obesity.
为研究膳食脂肪来源与能量限制对血浆瘦素水平的交互影响及其与胰岛素作用的关系，将大鼠分别喂食含鱼油、红花油或牛油（20%重量/重量）的饲料10周。大鼠分组自由采食或按自由采食量的85%或70%采食各饲料，脂肪摄入量保持恒定。不同程度的能量限制导致体重下降（P<0.001），且因所提供的膳食脂肪不同而有所差异。自由采食鱼油和红花油的组血浆瘦素浓度比牛油组高60%（P<0.05），尽管喂食鱼油的动物肾周脂肪量和脂肪细胞大小较小。能量限制使喂食鱼油和红花油的大鼠瘦素水平降低62%（P<0.05），而喂食牛油的动物未观察到变化。自由采食的鱼油组血浆胰岛素水平比其他两个饮食组低（P<0.05）。这些数据表明，食用富含多不饱和脂肪酸饮食的动物存在高瘦素血症效应，轻度能量限制可使其恢复到饱和脂肪摄入水平。因此，膳食脂肪酸组成独立于脂肪组织量，是饮食诱导肥胖中循环瘦素水平的重要决定因素。
