Lactate dehydrogenase in human renal carcinoma tissues

Lactate dehydrogenase (LDH) activity and isoenzyme were determined in 27 human renal carcinoma (RC) tissues. Although LDH-1 and LDH-2 were predominant in the normal kidney, a completely inverted isoenzyme pattern was observed in 16 carcinomas. The others, however, showed either a normal or an incompletely inverted pattern. The LDH activity in the tumours with a completely inverted pattern was significantly higher than the activity of incompletely inverted or normal kidney pattern. It was also found that the isoenzyme pattern was more closely correlated with cell type than the grade of malignancy of the tumour, 14 out of the 16 cases of the completely inverted pattern being of the clear cell type, and 9 out of the 11 cases of incompletely inverted or normal kidney pattern being of either granular cell or mixed cell type. These results seemed to well substantiate an opinion that in clear cells anaerobic glycolysis provides a major energy source, whereas granular cells seek energy source primarily in TCA cycle and subsequent oxidative phosphorylation.