Preedy V R, Pain V M, Garlick P J
Biochem J. 1984 Mar 1;218(2):429-40. doi: 10.1042/bj2180429.
Measures of perfusion adequacy in perfused rat hemicorpus preparations were investigated as potential indices of tissue function during studies of muscle protein metabolism. Perfusion under normal conditions for up to 80 min resulted in rates of protein synthesis and concentrations of ATP in muscle that were similar to those in vivo, but phosphocreatine in muscle gradually decreased and muscle lactate increased. Hypoxic conditions led to lower rates of protein synthesis, lower phospho-creatine and raised lactate contents in muscle compared with normal perfusions, and ATP was slightly decreased. Hypoxic preparations also released more lactate and K+ into the medium and had higher perfusion pressures, but glucose uptake and muscle water content were not altered. In totally ischaemic muscle, concentrations of ATP and phosphocreatine were even lower than in hypoxic muscle, and that of lactate was higher. From 11 preparations perfused for 60 min under normal conditions, three were selected on the basis of lower muscle ATP content than the others. Preparations with low ATP also showed lower muscle phosphocreatine concentrations, O2 uptake and CO2 output, as well as higher perfusion pressure and muscle lactate concentrations than in the remaining preparations, but muscle water, ADP and AMP concentrations and lactate and K+ flux were no different. In perfusions extended to 3 h, deterioration of function was more apparent. There were significant correlations between rates of protein synthesis and the concentrations of ATP, phosphocreatine and lactate in two different muscles (r = 0.756-0.929), but not with any of the other indices investigated. Taken overall, these experiments showed that concentrations of ADP, AMP and water in muscle, rates of lactate and glucose metabolism, K+ output, perfusion pressure and blood gas parameters were unsuitable for distinguishing unsound from sound preparations, because they did not consistently demonstrate differences, or could not be ascribed to only muscle metabolism. It was found that ATP, phosphocreatine and lactate concentrations in muscle were the best indicators of impaired metabolic state in studies of protein synthesis. Measurements of these could be used on a routine basis for rejecting unsatisfactory preparations.
在肌肉蛋白质代谢研究中，对灌注大鼠半体标本的灌注充足性指标进行了研究，以作为组织功能的潜在指标。在正常条件下灌注长达80分钟，肌肉中的蛋白质合成速率和ATP浓度与体内相似，但肌肉中的磷酸肌酸逐渐减少，肌肉乳酸增加。与正常灌注相比，缺氧条件导致肌肉中蛋白质合成速率降低、磷酸肌酸含量降低、乳酸含量升高，ATP略有下降。缺氧标本还向培养基中释放更多的乳酸和钾离子，灌注压力更高，但葡萄糖摄取和肌肉含水量未改变。在完全缺血的肌肉中，ATP和磷酸肌酸的浓度甚至低于缺氧肌肉，乳酸浓度更高。从11个在正常条件下灌注60分钟的标本中，根据肌肉ATP含量低于其他标本的情况选择了3个。ATP含量低的标本还显示出肌肉磷酸肌酸浓度、氧气摄取和二氧化碳输出较低，以及灌注压力和肌肉乳酸浓度高于其余标本，但肌肉水分、ADP和AMP浓度以及乳酸和钾离子通量没有差异。在延长至3小时的灌注中，功能恶化更为明显。两种不同肌肉中的蛋白质合成速率与ATP、磷酸肌酸和乳酸浓度之间存在显著相关性（r = 0.756 - 0.929），但与所研究的任何其他指标均无相关性。总体而言，这些实验表明，肌肉中的ADP、AMP和水分浓度、乳酸和葡萄糖代谢速率、钾离子输出、灌注压力和血气参数不适合区分健康标本和不健康标本，因为它们没有始终显示出差异，或者不能仅归因于肌肉代谢。发现在蛋白质合成研究中，肌肉中的ATP、磷酸肌酸和乳酸浓度是代谢状态受损的最佳指标。对这些指标的测量可常规用于排除不满意的标本。
