Mihas A A, Tavassoli M
Department of Medicine, VAMC, Jackson, MS 39216.
Am J Med Sci. 1991 May;301(5):299-304. doi: 10.1097/00000441-199105000-00001.
Chronic alcoholism has been reported to be associated with a reduced carbohydrate content of transferrin (TF), particularly, its reduced sialylation state. Low sialylation state of TF now serves as an objective marker of chronic alcohol abuse. To investigate the pathophysiological significance of this finding in relation to hepatic siderosis, also commonly associated with chronic alcoholism, the authors have investigated the effect of ethanol on the uptake, binding, and desialylation of transferrin by isolated rat liver endothelium in vitro. In pulse-chase experiments, transferrin labeled with either 125I (protein-labeled) or 3H (sialic acid-labeled) was incubated with isolated, fractionated liver endothelium with and without ethanol, and the supernates were subjected to column chromatography using RCA120- agarose. Incubation of the endothelium with increasing concentrations of ethanol resulted in a progressive increase in the desialylation rate of transferrin which was maximal when 160 mM concentration of ethanol was used. These data indicate that ethanol significantly promotes the desialylation of transferrin by rat liver endothelium. The implications of these findings in the pathogenesis of hepatic siderosis of the alcoholic are discussed.
据报道，慢性酒精中毒与转铁蛋白（TF）的碳水化合物含量降低有关，尤其是其唾液酸化状态降低。TF的低唾液酸化状态现在是慢性酒精滥用的一个客观标志物。为了研究这一发现与同样常见于慢性酒精中毒的肝铁沉积症相关的病理生理意义，作者在体外研究了乙醇对分离的大鼠肝内皮细胞摄取、结合和去唾液酸化转铁蛋白的影响。在脉冲追踪实验中，将用125I（蛋白质标记）或3H（唾液酸标记）标记的转铁蛋白与有或无乙醇的分离的分级肝内皮细胞一起孵育，然后将上清液用RCA120-琼脂糖进行柱色谱分析。用浓度不断增加的乙醇孵育内皮细胞导致转铁蛋白去唾液酸化率逐渐增加，当使用160 mM乙醇浓度时达到最大值。这些数据表明，乙醇显著促进大鼠肝内皮细胞对转铁蛋白的去唾液酸化作用。本文讨论了这些发现对酒精性肝病患者肝铁沉积症发病机制的影响。
