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Lipoprotein metabolism in eel.

鳗鱼的脂蛋白代谢。

基本信息

批准号：
07660274
负责人：
HAYASHI Seiichi
金额：
$ 1.41万
依托单位：
Kagoshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

Plasma lipid concentration of fishes such as eel, carp and raibowtrout is several times higher than that of familial hypercholesterolemia and hypertriglycemia of human beings, but the reason is unknown. Studies of lipoprotein metabolism in fish are conducted to solve the question described above since most of plasma lipid exist as components of lipoproteins.Four major subjects are studied to investigate lipoprotein metabolism using cultured eel hepatocytes. 1. HDL receptor of eel hepatocytes was investigated using HDL labelled with a lipophilic fluorescent dye, which was synthesized in our laboratory. It was found that HDL receptor existed on eel hepatocytes and the Kd value for HDL was about 20 mug HDL / ml. Furthermore, HDL stimulated a lipoprotein synthesis and secretion in the hepatocytes. 2. It is a remarkable characteristic of fish oil that rather high amount of polyunsaturated fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid is contained in fish oils. Then effect of DHA on lipoprotein synthesis and secretion was investigated. DHA stimulated synthesis of lipoprotein, triacylglycerol and cholesterol, but remarkably inhibited the secretion of lipoprotein. 3. It is known that migration of fishes such as eel has a relationship with thyroid hormone. Effect of T4 on lipoprotein synthesis was investigated. T4 stimulated lipogenesis as well as lipoprotein synthesis. 4. Lipoprotein synthesis and serum lipoproteins of silver eel, which migrates from the river to the sea for spawning, were compared with those of cultured eel, which is sexually immature. Silver eel hepatocytes actively synthesized lipoprotein compared to hepatocytes of cultured eel and the secreted lipoprotein by silver eel hepatocytes had higher ratio of lipid than that by cultured eel hepatocytes. Contrary to secreted lipoprotein, serum lipoproteins of silver eel had lower lipid ratio than those of cultured eel.

鳗鱼、鲤鱼、鲑鱼等鱼类的血脂浓度比人类家族性高胆固醇血症和高甘油三酯血症高出数倍，但其原因尚不清楚。为了解决上述问题，我们开展了对鱼类脂蛋白代谢的研究，因为大多数血浆中的脂质是以脂蛋白的成分存在的。本论文以四个主要研究对象为研究对象，利用培养的鳗鱼肝细胞来研究脂蛋白代谢。1.用自制的亲脂性荧光染料标记的高密度脂蛋白对鳗鱼肝细胞的高密度脂蛋白受体进行了研究。结果表明，鳗鱼肝细胞上存在高密度脂蛋白受体，高密度脂蛋白的Kd值约为20µg/ml，并能刺激肝细胞内脂蛋白的合成和分泌。2.鱼油中含有较高的二十二碳六烯酸(DHA)和二十碳五烯酸等多不饱和脂肪酸是鱼油的一个显著特点。然后观察DHA对脂蛋白合成和分泌的影响。DHA可促进脂蛋白、三酰甘油和胆固醇的合成，但显著抑制脂蛋白的分泌。3.已知鳗鱼等鱼类的迁徙与甲状腺激素有关。观察T4对脂蛋白合成的影响。T4刺激脂肪生成和脂蛋白合成。4.比较了从河水中迁徙到大海产卵的银鳗与养殖的性未成熟鳗鱼的脂蛋白合成和血清脂蛋白。与养殖鳗鱼肝细胞相比，银鳗肝细胞主动合成脂蛋白，分泌的脂蛋白比例高于养殖鳗鱼肝细胞。与分泌型脂蛋白相反，银鳗血清脂蛋白的脂比低于养殖鳗。