Elsing C, Górski J, Boeker C, Stremmel W
Department of Medicine, University of Heidelberg, Germany.
Cell Mol Life Sci. 1998 Jul;54(7):744-50. doi: 10.1007/s000180050202.
Studies of regulation of free fatty acid (FFA) utilization by skeletal muscles have focused on plasma FFA delivery and on intracellular factors affecting FFA metabolism. The present study was conducted to directly analyse the uptake process of fatty acids into single myocytes. Cells were isolated from the rat flexor digitorum brevis muscle. Confocal laser scanning microscopy was utilized to analyse the uptake of the fluorescent fatty acid derivative 12-NBD-stearate, which is not metabolized by muscle tissue. Uptake represented a saturable function of the unbound fatty acid concentration in the medium (K(m) 366 +/- 118 nM, Vmax 2.1 +/- 0.3 AU/s) and depended on the medium sodium concentration. Reduced buffer pH increased initial uptake rates, whereas lactate (10 mM) had no effect. Membrane hyper- and depolarization decreased uptake rates. This study demonstrates for the first time kinetic data from isolated myocytes with evidence for a carrier-mediated transport mechanism for long-chain fatty acids.
关于骨骼肌对游离脂肪酸（FFA）利用的调节研究主要集中在血浆FFA的输送以及影响FFA代谢的细胞内因素上。本研究旨在直接分析脂肪酸进入单个肌细胞的摄取过程。细胞取自大鼠趾短屈肌。利用共聚焦激光扫描显微镜分析荧光脂肪酸衍生物12-NBD-硬脂酸的摄取情况，该衍生物不会被肌肉组织代谢。摄取表现为培养基中未结合脂肪酸浓度的饱和函数（K(m) 366 +/- 118 nM，Vmax 2.1 +/- 0.3 AU/s），且依赖于培养基中的钠浓度。缓冲液pH降低会增加初始摄取速率，而乳酸（10 mM）则无影响。膜的超极化和去极化会降低摄取速率。本研究首次展示了来自分离肌细胞的动力学数据，并证明了长链脂肪酸存在载体介导的转运机制。
