Piper H M, Spahr R, Krützfeldt A, Siegmund B, Schwartz P, Pau H
Physiologisches Institut I, Universität Düsseldorf, F.R.G.
Exp Eye Res. 1990 Aug;51(2):131-8. doi: 10.1016/0014-4835(90)90064-2.
Energy metabolism of bovine cultured lens epithelial cells (CLEC) was compared to that of fresh bovine lens. CLEC contained high levels of ATP (44 nmol mg protein-1) and creatine phosphate (13 nmol mg protein-1). An ATP/ADP ratio of ten and a creatine phosphate/creatine ratio of two indicated the cells were in a well-energized state. ATP concentration in fresh epithelium was comparable to that of CLEC; however in the anterior cortex it was tenfold lower. In contrast to fresh lenses, CLEC were able to oxidize glucose, lactate and palmitic acid. Lactate was oxidized at the highest rate. In CLEC, 42% of the ATP generated by catabolizing glucose resulted from oxidative phosphorylation. Glucose (5 mM) was degraded to lactate and CO2 at a 2:1 ratio. The hexose monophosphate pathway accounted for two thirds of the CO2 produced. In the fresh whole bovine lens palmitate was not oxidized and lactate was oxidized to a lesser degree than in CLEC. Only one-tenth of the ATP generated by glucose catabolism in the fresh whole lens was derived from oxidative phosphorylation. This was also the case for a preparation of fresh epithelium, maintained in air and 100% oxygen, demonstrating that the preferential glycolytic catabolism of glucose in lens is not caused by limited oxygen diffusion. In the fresh bovine lens the epithelium accounted for one third of the glucose catabolism of the whole lens, even though it had only about 0.1% of its protein mass. In fresh human lenses, conversion of glucose into lactate was even more pronounced--the lactate/CO2 ratio was 73:1.(ABSTRACT TRUNCATED AT 250 WORDS)
将牛培养的晶状体上皮细胞（CLEC）的能量代谢与新鲜牛晶状体的能量代谢进行了比较。CLEC含有高水平的ATP（44 nmol mg蛋白-1）和磷酸肌酸（13 nmol mg蛋白-1）。ATP/ADP比值为10，磷酸肌酸/肌酸比值为2，表明细胞处于能量充足的状态。新鲜上皮中的ATP浓度与CLEC相当；然而，在前皮质中，其浓度要低10倍。与新鲜晶状体不同，CLEC能够氧化葡萄糖、乳酸和棕榈酸。乳酸的氧化速率最高。在CLEC中，通过分解葡萄糖产生的ATP中有42%来自氧化磷酸化。葡萄糖（5 mM）以2:1的比例降解为乳酸和CO2。磷酸戊糖途径占产生的CO2的三分之二。在新鲜的完整牛晶状体中，棕榈酸不被氧化，乳酸的氧化程度低于CLEC。在新鲜完整晶状体中，由葡萄糖分解代谢产生的ATP中只有十分之一来自氧化磷酸化。对于在空气和100%氧气中保存的新鲜上皮制剂也是如此，这表明晶状体中葡萄糖优先的糖酵解分解代谢不是由有限的氧气扩散引起的。在新鲜牛晶状体中，上皮细胞占整个晶状体葡萄糖分解代谢的三分之一，尽管其蛋白质质量仅约为0.1%。在新鲜人晶状体中，葡萄糖向乳酸的转化更为明显——乳酸/CO2比值为73:1。（摘要截短至250字）
