Power G W, Newsholme E A
Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
J Nutr. 1997 Nov;127(11):2142-50. doi: 10.1093/jn/127.11.2142.
The fatty acid composition of the diet has been found to influence the activity and sensitivity of mitochondrial carnitine palmitoyltransferase I (CPT I; EC 2.3.1.21) to inhibition by malonyl CoA in rat heart and skeletal muscle. The nutritional state of rats has been shown to have less influence on the activity and metabolic control of mitochondrial CPT I in heart and skeletal muscle tissue than in the liver, a tissue in which CPT I activity and sensitivity to inhibition by malonyl CoA can be shown to be regulated acutely under different nutritional conditions. However, because manipulation of the nutritional state in these previous studies was restricted mainly to examining the effect of starvation, this study was undertaken to determine whether, as in liver, the fatty acid content and composition of the diet can regulate the activity and metabolic control of CPT I in heart and skeletal muscle. Rats were fed for up to 10 wk either a nonpurified low fat diet (30 g fat/kg) or a high fat diet (200 g fat/kg) containing one of the following five oil types: hydrogenated coconut oil (HCO), olive oil (OO), safflower oil (SO), evening primrose oil (EPO) or menhaden (fish) oil (MO). Feeding a diet enriched in MO had the most pronounced effect. Rats fed MO had a significantly greater skeletal muscle CPT I specific activity and tissue capacity, and a lower sensitivity of CPT I to malonyl CoA inhibition compared with rats fed a low fat diet, but the duration of feeding required to modulate this sensitivity was longer than that observed previously for the liver enzyme. Progressively greater sensitivity of heart CPT I to malonyl CoA occurred with feeding duration in all groups. These studies indicate that the fatty acid composition of the diet is involved in the regulation of mitochondrial CPT I activity in heart and skeletal muscle.
已发现饮食中的脂肪酸组成会影响大鼠心脏和骨骼肌中线粒体肉碱棕榈酰转移酶I（CPT I；EC 2.3.1.21）对丙二酰辅酶A抑制的活性和敏感性。与肝脏相比，大鼠的营养状态对心脏和骨骼肌组织中线粒体CPT I的活性和代谢控制的影响较小，在肝脏中，CPT I的活性以及对丙二酰辅酶A抑制的敏感性在不同营养条件下可表现出急性调节。然而，由于在这些先前的研究中对营养状态的操控主要限于研究饥饿的影响，因此开展本研究以确定饮食中的脂肪酸含量和组成是否能像在肝脏中一样调节心脏和骨骼肌中CPT I的活性和代谢控制。将大鼠喂食长达10周，分别给予未纯化的低脂饮食（30 g脂肪/kg）或含有以下五种油类之一的高脂饮食（200 g脂肪/kg）：氢化椰子油（HCO）、橄榄油（OO）、红花油（SO）、月见草油（EPO）或鲱鱼油（MO）。喂食富含MO的饮食产生的影响最为显著。与喂食低脂饮食的大鼠相比，喂食MO的大鼠骨骼肌CPT I的比活性和组织容量显著更高，且CPT I对丙二酰辅酶A抑制的敏感性更低，但调节这种敏感性所需的喂食持续时间比先前观察到的肝脏酶的持续时间更长。在所有组中，随着喂食持续时间的延长，心脏CPT I对丙二酰辅酶A的敏感性逐渐增加。这些研究表明，饮食中的脂肪酸组成参与了心脏和骨骼肌中线粒体CPT I活性的调节。
