Reibel D K, O'Rourke B, Foster K A
Am J Physiol. 1987 Mar;252(3 Pt 2):H561-5. doi: 10.1152/ajpheart.1987.252.3.H561.
Carnitine levels are reduced in hypertrophied hearts of rats subjected to aortic constriction (banding) and elevated in hypertrophied hearts of spontaneously hypertensive rats (SHR). In an attempt to determine the mechanisms for these alterations, L-[14C]carnitine transport was examined in isolated perfused hearts. Total carnitine uptake was significantly reduced by approximately 20% in hypertrophied hearts of banded rats at all perfusate carnitine concentrations employed. The reduction in total uptake was due to a 40% reduction in carrier-mediated carnitine uptake with no difference in uptake by diffusion. In contrast, carnitine uptake was not altered in isolated hypertrophied hearts of SHR. However, serum carnitine levels were elevated in SHR, which could result in increased myocardial carnitine uptake in vivo. The data suggest that altered carnitine content in hypertrophied hearts of aortic-banded rats is due to an alteration in the carrier-mediated carnitine transport system in the myocardium. However, altered carnitine content in hypertrophied hearts of SHR is not due to a change in the carnitine transport system per se but may rather be due to a change in serum carnitine levels.
在接受主动脉缩窄（结扎）的大鼠肥厚心脏中，肉碱水平降低；而在自发性高血压大鼠（SHR）的肥厚心脏中，肉碱水平升高。为了确定这些变化的机制，对离体灌注心脏中的L-[14C]肉碱转运进行了检测。在所采用的所有灌注液肉碱浓度下，结扎大鼠的肥厚心脏中总肉碱摄取量显著降低了约20%。总摄取量的降低是由于载体介导的肉碱摄取减少了40%，而扩散摄取没有差异。相比之下，SHR离体肥厚心脏中的肉碱摄取没有改变。然而，SHR的血清肉碱水平升高，这可能导致体内心肌肉碱摄取增加。数据表明，主动脉结扎大鼠肥厚心脏中肉碱含量的改变是由于心肌中载体介导的肉碱转运系统发生了改变。然而，SHR肥厚心脏中肉碱含量的改变并非由于肉碱转运系统本身的变化，而可能是由于血清肉碱水平的变化。
