Fletcher J E, Erwin K, Beech J
Department of Anesthesiology, Hahnemann University, Philadelphia, PA 19102-1192.
Biochim Biophys Acta. 1993 Jul 1;1168(3):292-8. doi: 10.1016/0005-2760(93)90185-c.
Previous studies have demonstrated that phenytoin decreases the levels of triacylglycerols in several tissues other than skeletal muscle. Since phenytoin is clinically effective in several skeletal muscle disorders, triacylglycerol metabolism in skeletal muscle from four normal Quarter horses and four Quarter horses with hyperkalemic periodic paralysis was examined. The horses with hyperkalemic periodic paralysis had low levels of 18:3 in the phospholipids, low levels of 16:0, 16:1 and 18:3 in the free fatty acids and low levels of 20:4 in triacylglycerols. Triacylglycerol levels were increased in skeletal muscle from seven (three controls, four hyperkalemic periodic paralysis) of the eight horses on treatment with oral phenytoin for one week. Instead of an increase in all fatty ester types only 16:0, 16:1, 18:1 and 18:2 were significantly increased. Total lipid phosphorus and the distribution of phospholipid fatty esters and free fatty acids were not significantly altered by phenytoin treatment in most cases. An alteration in triacylglycerol metabolism by phenytoin was also observed in primary cultures of normal equine skeletal muscle radiolabeled with 18:1, but not in those radiolabeled with 18:2. These findings suggest that phenytoin does not just increase the levels of triacylglycerol in skeletal muscle, but alters the utilization and incorporation of fatty esters. These findings suggest a potential involvement of triacylglycerol metabolism in the clinical efficacy of phenytoin in hyperkalemic periodic paralysis.
以往研究表明，苯妥英可降低骨骼肌以外其他几种组织中的甘油三酯水平。鉴于苯妥英在几种骨骼肌疾病中具有临床疗效，我们检测了4匹正常夸特马和4匹患有高钾性周期性麻痹的夸特马骨骼肌中的甘油三酯代谢情况。患有高钾性周期性麻痹的马匹，其磷脂中的18:3水平较低，游离脂肪酸中的16:0、16:1和18:3水平较低，甘油三酯中的20:4水平较低。在8匹马中，有7匹（3匹对照马、4匹高钾性周期性麻痹马）经口服苯妥英治疗1周后，骨骼肌中的甘油三酯水平升高。并非所有脂肪酸酯类型都增加，只有16:0、16:1、18:1和18:2显著增加。在大多数情况下，苯妥英治疗并未显著改变总脂质磷以及磷脂脂肪酸酯和游离脂肪酸的分布。在用18:1进行放射性标记的正常马骨骼肌原代培养物中也观察到苯妥英对甘油三酯代谢的改变，但在用18:2进行放射性标记的培养物中未观察到。这些发现表明，苯妥英不仅会增加骨骼肌中甘油三酯的水平，还会改变脂肪酸酯的利用和掺入。这些发现提示甘油三酯代谢可能参与了苯妥英治疗高钾性周期性麻痹的临床疗效。
