Kanazawa A, Shirota Y, Fujimoto K
Department of Applied Biological Chemistry, Faculty of Agriculture, Tohoku University, Sendai, Japan.
Lipids. 1997 Jul;32(7):737-44. doi: 10.1007/s11745-997-0094-0.
Rats were fed a diet supplemented with corn oil (n-3 deficient), soy oil, or a mixture containing 8% 22:6n-3 ethyl ester for 6 wk. The hepatic capacities for the beta-oxidation and synthesis of 22:6n-3, in addition to the acylation of lysophosphatidate, were tested in vitro. In rats that were fed a 22:6n-3-enriched diet, both the beta-oxidation of 22:6n-3 and elongation of 20:5n-3 were enhanced compared to those in rats fed the other diets. Acylation of lysophosphatidate was also enhanced in rats fed a 22:6n-3-enriched diet, while the rate of dephosphorylation of phosphatidate was not changed. The amount of 22:6n-3 in the liver was much less than that consumed in a docosahexaenoic acid-enriched diet. These results suggest that a significant amount of dietary 22:6n-3 was degraded via beta-oxidation, and that a portion of the retroconverted 20:5n-3 was recycled for the synthesis of 22:6n-3. The recycling of 20:5n-3 might contribute to the low level of 22:6n-3 in rats fed an n-3-deficient diet.
给大鼠喂食补充了玉米油（缺乏n-3）、大豆油或含有8% 22:6n-3乙酯的混合物的饲料，持续6周。体外测试了肝脏对22:6n-3的β-氧化和合成能力，以及溶血磷脂酸的酰化能力。与喂食其他饲料的大鼠相比，喂食富含22:6n-3饲料的大鼠，22:6n-3的β-氧化和20:5n-3的延长均增强。喂食富含22:6n-3饲料的大鼠，溶血磷脂酸的酰化也增强，而磷脂酸的去磷酸化速率未改变。肝脏中22:6n-3的含量远低于富含二十二碳六烯酸饲料中的消耗量。这些结果表明，大量膳食中的22:6n-3通过β-氧化降解，并且部分逆向转化的20:5n-3被循环用于合成22:6n-3。20:5n-3的循环可能导致喂食缺乏n-3饲料的大鼠体内22:6n-3水平较低。
