Role of unsaturated fatty acids in brown adipose tissue function - with special reference to docosahexaenoic acid.

为了阐明细胞膜磷脂n-3多不饱和脂肪酸(DHA)的作用，研究了不同条件下大鼠棕色脂肪组织(BAT)中DHA的变化。(1)新生儿期DHA和花生四烯酸(AA)水平较高，BAT发热率高于成人。(2)日粮中添加DHA增加了BAT-DHA，降低了AA，导致BAT体外发热率不变或降低。(3)缺乏DHA的饲料降低了BAT-DHA的体外产热能力，但不影响AA。(4)添加DHA和AA的饲料增加了蝙蝠体内的这两种脂肪酸，但不改变BAT的体外产热能力。而解偶联蛋白1mRNA表达增加。(5)慢性给予一氧化氮合酶L-NAME不改变BAT-DHA，但由于细胞密度降低，降低了BAT的体外发热率。(6)热习服或禁食降低了BAT-DHA和体外产热能力，且两者之间存在相关性。(7)甲减可降低DHA和AA，导致BAT体外发热率降低。三碘甲腺原氨酸诱导的甲亢增加了BAT在体外因增殖而产生的产热，而DHA无明显变化。(8)初生至幼龄阶段较低的饲养温度影响了蝙蝠持续的体外产热和系统的非颤抖产热。提示DHA可能是BAT生热功能的控制因子之一。

In an attempt to elucidate a role of membrane phospholipid n-3 polyunsaturated fatty acid (DHA) , the changes in DHA of rat brown adipose tissue (BAT) were studied under various conditions. (1) DHA and arachidonic acid (AA) were higher during neonatal period with higher BAT thermogenesis than in the adults. (2) DHA-supplemented diet increased BAT-DHA but decreased AA, resulting in the unchanged or decreased BAT in vitro thermogenesis. (3) DHA-deficient diet decreased BAT-DHA but not AA without BAT in vitro thermogenesis. (4) DHA plus AA-supplemented diet increased both fatty acids in BAT but did not change BAT in vitro thermogenesis. However, uncoupling protein 1 mRNA expression increased. (5) Chronic administration of nitric oxide synthase L-NAME did not change BAT-DHA, but decreased BAT in vitro thermogenesis due to decreased cellularity. (6) Heat acclimation or fasting decreased BAT-DHA and in vitro thermogenesis with correlation between these both parameters. (7) Methimazole-induced hypothyroidism decrease both DHA and AA, causing the decrease in BAT in vitro thermogenesis. Triiodothyronine-induced hyperthyroidism increased BAT in vitro thermogenesis due to hyperplasia without the changes of DHA. (8) Low rearing temperature during the neonatal to young period effected the long-lasting improved BAT in vitro thermogenesis as well as systemic nonshivering thermogenesis in later life. These findings suggest that DHA subserves as one of controlling factors of BAT thermogenic function.