Altered LDH Isozymes in Brain Tumors

Abstract

NEOPLASMS have been shown to have different metabolic characteristics than normal tissues. Warburg¹observed a greater tendency to derive energy from anaerobic glycolysis with the production of increased amounts of lactic acid. He later suggested that an early step in the development of a neoplasm was a disturbance in cellular respiratory activity.²Heller and Elliott showed that the rate of glycolysis was higher in human brain tumors than in normal gray matter when considered in relation to their respiratory rate.³Hill and Levi⁴noted that lactic dehydrogenase (LDH), the enzyme at the end of the metabolic chain of anaerobic glycolysis, was elevated in the serum of some patients with neoplastic disease. Increased amount of lactate and LDH have been found in brain tumor homogenates.⁵ In recent years it has been shown that the LDH activity of serum or tissue extracts is not