QUANTITATIVE ESTIMATION OF PHYSIOLOGICAL EFFECT OF N-3 AND N-6 POLYUNSATURATED FATTY ACIDS IN RATS

定量评价了饲料中亚油酸、γ -亚麻酸、花生四烯酸、α -亚麻酸、二十碳五烯酸（EPA）和二十二碳六烯酸（DHA）对大鼠脂质代谢的影响。饲料中EPA和DHA降低血清和肝脏甘油三酯浓度。膳食DHA也能降低血清胆固醇浓度。EPA和DHA降低甘油三酯的作用被认为是由于抑制脂肪酸和甘油三酯在肝脏的合成。通过注射Triton WR-1339估计肝脏中甘油三酯和胆固醇的分泌受到膳食EPA和DHA的抑制。饲粮中添加γ -亚麻酸和花生四烯酸可提高血清、肝脏、心脏、主动脉和血小板中花生四烯酸、磷脂酰胆碱和磷脂酰乙醇胺含量。相反，饲粮中添加n-3多不饱和脂肪酸（PUFA）可降低花生四烯酸含量。DHA对降低磷脂中的花生四烯酸最有效。脑磷脂中花生四烯酸含量不受膳食多聚脂肪酸的影响。喂食n-3 PUFA可减少血小板血栓素A2的生成。DHA对降低产量最有效。相比之下，尽管饲粮中n-3 PUFA与亚油酸的效果相当，但饲粮中添加-lonolenic和花生四烯酸可提高主动脉前环素的生成。饲料中EPA和DHA对血小板聚集的抑制指标原环素和血栓素A2的比值高于其他PUFA组。膳食DHA抑制自发性高血压大鼠的收缩压。结果表明，EPA和DHA比其他PUFA具有更强的降血脂和抗血栓作用。

Effects of dietary linoleic, gamma-linolenic, arachidonic, alpha-linolenic, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids on lipid metabolism were quntitatively estimated in rats. Dietary EPA and DHA lowered serum and liver triglyceride concentration. Dietary DHA also lowered serum cholesterol concentration. The triglyceride lowering effect of EPA and DHA was thought to be due to the suppression of fatty acid and triglyceride synthesis in liver. Secretion of triglyceride and cholesterol from liver estimated by the injection of Triton WR-1339 was suppressed by dietary EPA and DHA.Dietary gamma-linolenic and arachidonic acids increased arachidonic acid content in serum, liver, heart, aorta and platelet phosphatidylcholine and phosphatidylethanolamine. In contrast, dietary n-3 polyunsaturated fatty acids (PUFA) decreased the arachidonic acid content. DHA was most effective to lower arachidonic acid in the phospholipids. Arachidonic acid content in brain phospholipids were not influenced by the dietary PUFA.Production of platelet thromboxane A2 was decreased by the feeding of n-3 PUFA.DHA was most effective to lower the production. In contrast, production of aortic prostacyclin was enhanced by the feeding of gamma-lonolenic and arachidonic acids, although dietary n-3 PUFA had a comparable effect with linoleic acid. The ratio of protsacyclin and thromboxane A2, an index of inhibition of platelet aggregation, was higher in dietary EPA and DHA than the other PUFA groups. Dietary DHA suppressed systolic blood pressure in spontaneously hypertensive rats. The results suggest that EPA and DHA are more hypolipidemic and antithrombotic than the other PUFA.