Lactic Dehydrogenase in Kidney Tissue and Renal Disease

The concentration of lactic dehydrogenase (LDH) and LDH isoenzymes was determined in different zones of normal human kidneys and in sera from patients with renal diseases. The isoenzyme pattern in renal tissue was characterized by an increasing, relative concentration of the M‐subunit from the cortex to the papilla. The outer non‐glomerular cortex corticis zone presented a medulla‐like isoenzyme pattern which has not been described hitherto. This correlated well with new data on renal blood flow in this zone. Patients with chronic renal failure had normal or slightly elevated serum concentrations of LDH, and the isoenzyme pattern was inconclusive. In patients with renal traumata, serum LDH concentration was very high, but the isoenzyme pattern did not differ from the normal. In acute oliguric glomerulonephritis, serum LDH was moderately elevated, while LDH concentrations were usually very high in acute renal failure of widely different pathogenesis. In both groups, however, the isoenzyme pattern exhibited a uniform relative increase of the M‐subunit concentration. Taking into consideration new data on (a) renal blood flow in acute renal failure, and (b) adaptation of LDH synthesis to varying oxygen tension, the hypothesis is advanced that the isoenzyme pattern reflects an altered synthesis of LDH in the kidneys as an adaptive response to hypoxia in the initial phase of acute renal failure.