Studies on urinary isozymes of lactic dehydrogenase and β-glucuronidase in patients with bladder tumors

Isozymes of urinary lactic dehydrogenase (LDH) were studied in 55 subjects, including 17 patients with bladder tumors. Normal clear urine from healthy persons showed little activity of LDH5, but in 11 out of 17 patients with bladder tumors LDH5 was increased sufficiently to invert the ratio of LDH5/LDH1,although the urine was not contaminated appreciably with leucocytes. Studies on tissue LDH isozymes in 16 tumor specimens strongly suggested that the increased LDH5 in the urine of patients with bladder tumors originated from the tumors themselves. β-Glucuronidase (β-G) isozymes were studied in urine specimens from 10 normal subjects, and 10 patients with bladder tumors and in 5 specimens of normal epithelium and 5 of tumor tissue. Two or three distinct bands of β-G were separated from specimens of urine and tumor tissue from patients with bladder tumors, but only a single band was found in specimens from normal subjects.