Parrish C C, Pathy D A, Parkes J G, Angel A
Department of Medicine, University of Toronto, Canada.
J Cell Physiol. 1991 Sep;148(3):493-502. doi: 10.1002/jcp.1041480323.
Dietary fish oils, enriched with omega-3 fatty acids (e.g., MaxEPA fish oil), inhibit lipogenesis and have a marked hypotriglyceridemic effect in man and experimental animals. Dietary omega-3 fatty acids also reduce adipose tissue trophic growth in rats. To understand the metabolic basis for this, we measured the effect of fish oil feeding upon rat plasma triglyceride concentration, fat pad mass, fat cell size, fat cell lipolysis, as well as lipoprotein binding to adipocyte plasma membranes. In adolescent (250 g) male Wistar rats fed 20% (w/w) fish oil supplemented diets for 3 weeks, plasma triglyceride levels and epididymal and perirenal fat pad mass were significantly (P less than 0.005) reduced compared to pair-fed controls given 20% lard diets. These differences in fat pad mass between the diets were greater than differences in whole animal mass or in the mass of livers, testes, kidneys, spleens, or hearts. Isoproterenol-stimulated lipolysis was significantly (P less than 0.005) higher in fish oil fed rats than in pair-fed controls. In young (100 g) rats plasma triglyceride levels were 10 times lower in the fish oil fed group after 5 weeks as compared to the lard-fed controls. This was accompanied by a reduction in epididymal and perirenal fat pad mass as well as a 2-3-fold decrease in adipocyte volumes; there was no significant difference between the two groups in fat cell number in each region. Plasma membranes of epididymal adipocytes from fish oil fed rats bound significantly (P less than 0.001) less HDL1 than the lard-fed rats, possibly as a result of a reduction in fat cell size and/or alteration of plasma membrane structure. Thus in both young and old rats, the reduction in plasma triglyceride concentration in conjunction with increased hormone-stimulated lipolysis may explain in part the selective reduction in adipose tissue trophic growth accompanying fish oil consumption.
富含ω-3脂肪酸的膳食鱼油（如MaxEPA鱼油）可抑制脂肪生成，并对人和实验动物具有显著的降甘油三酯作用。膳食中的ω-3脂肪酸还可减少大鼠脂肪组织的营养性生长。为了解其代谢基础，我们测定了喂食鱼油对大鼠血浆甘油三酯浓度、脂肪垫质量、脂肪细胞大小、脂肪细胞脂解以及脂蛋白与脂肪细胞质膜结合的影响。在青春期（250克）雄性Wistar大鼠中，喂食含20%（w/w）鱼油补充剂的饲料3周后，与喂食含20%猪油饲料的配对对照组相比，血浆甘油三酯水平以及附睾和肾周脂肪垫质量显著降低（P<0.005）。不同饲料组之间脂肪垫质量的差异大于全身体质量或肝脏、睾丸、肾脏、脾脏或心脏质量的差异。异丙肾上腺素刺激的脂解在喂食鱼油的大鼠中显著高于配对对照组（P<0.005）。在幼龄（100克）大鼠中，喂食鱼油组5周后的血浆甘油三酯水平比喂食猪油的对照组低10倍。这伴随着附睾和肾周脂肪垫质量的减少以及脂肪细胞体积减少2至3倍；两组在每个区域的脂肪细胞数量上没有显著差异。喂食鱼油的大鼠附睾脂肪细胞的质膜与高密度脂蛋白1（HDL1）的结合显著少于喂食猪油的大鼠（P<0.001），这可能是脂肪细胞大小减小和/或质膜结构改变的结果。因此，在幼龄和老龄大鼠中，血浆甘油三酯浓度的降低以及激素刺激的脂解增加可能部分解释了食用鱼油后脂肪组织营养性生长的选择性降低。
