Urinary
enzyme levels were investigated in rats administered different promoters in their diet for 32 weeks after being initiated by treatment with 0.05%
N-butyl-N-(4-hydroxybutyl)nitrosamine in their
drinking water for 4 weeks. All groups were composed of 10 rats each. Group 1: females treated with 3%
uracil (100%
carcinoma incidence). Group 2: control females kept on basal diet only (0%
carcinoma incidence). Group 3: males treated with 5%
sodium L-ascorbate (100%
carcinoma incidence). Group 4: control males (0%
carcinoma incidence). Urine was collected at the end of weeks 12, 24 and 36 and tested for
lactate dehydrogenase (LDH),
alkaline phosphatase, N-acetyl-beta-D-glucosaminase and
aspartate aminotransferase activity. To facilitate comparison, data were related to the corresponding excreted
creatinine levels. All measurements were made using a centrifugal automatic analyzer. The urine of rats with
cancer lesions (groups 1 and 3) showed significant elevation in all
enzyme activities at weeks 24 and/or 36 except for LDH in females (group 1). The M/H ratio of the LDH
isozymes was reversed (1.10 +/- 0.10) in the tested rats with
carcinomas at week 36. This study thus provides evidence of a correlation between high urinary
enzyme levels and
cancer development in the rat bladder. Measurement of the tested
enzymes might thus provide a method to detect malignant changes in bladder epithelium by direct urine analysis.