Burczynski F J, Cai Z S, Moran J B, Geisbuhler T, Rovetto M
Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
Am J Physiol. 1995 Apr;268(4 Pt 2):H1659-66. doi: 10.1152/ajpheart.1995.268.4.H1659.
The mechanisms regulating the cellular uptake of long-chain fatty acids are poorly understood. Although there is evidence that hepatocytes facilitate the uptake of ligands from the protein-bound fraction, it is not known whether cardiac myocytes also facilitate the uptake process. The present studies were designed to address the role of albumin in the uptake of long-chain fatty acids by cardiac myocytes isolated from adult male rats. At low albumin concentrations (1 microM), the myocyte palmitate clearance rate did not exceed that predicted by the diffusion-reaction model. At high albumin concentrations (300 and 600 microM), the clearance ratio test was used to determine whether myocytes facilitate the uptake of palmitate. As with the low albumin concentrations, the diffusion-reaction model accounted for the overall clearance rates. Because endothelial cells might be involved in enhancing fatty acid transport into myocytes, we also determined the effects of endothelial cells on palmitate uptake by cardiac myocytes. Based on cell number, the palmitate clearance rate by endothelial cells in the presence of albumin was only 7% of the cardiac myocyte clearance rate. Combining the endothelial cells with the myocytes did not result in any synergistic effect on the palmitate clearance rate.
目前对调节长链脂肪酸细胞摄取的机制了解甚少。尽管有证据表明肝细胞有助于从蛋白质结合部分摄取配体，但尚不清楚心肌细胞是否也促进摄取过程。本研究旨在探讨白蛋白在成年雄性大鼠分离的心肌细胞摄取长链脂肪酸中的作用。在低白蛋白浓度（1 microM）下，心肌细胞棕榈酸清除率不超过扩散反应模型预测的值。在高白蛋白浓度（300和600 microM）下，采用清除率试验来确定心肌细胞是否促进棕榈酸的摄取。与低白蛋白浓度时一样，扩散反应模型解释了总体清除率。由于内皮细胞可能参与增强脂肪酸向心肌细胞的转运，我们还确定了内皮细胞对心肌细胞摄取棕榈酸的影响。基于细胞数量，在有白蛋白存在的情况下，内皮细胞的棕榈酸清除率仅为心肌细胞清除率的7%。将内皮细胞与心肌细胞结合对棕榈酸清除率没有产生任何协同作用。
