Arginase activity determination. A marker of large bowel mucosa proliferation.

Arginase activity of the intestinal mucosa was tested as a proliferative marker in the adenoma-carcinoma sequence. The enzyme activity was determined by an end-point colorimetric method with L-arginine as substrate. Arginase activity was evaluated in 430 biopsy samples of large bowel mucosa, polyps and cancer tissue. The activities (U/g protein, mean +/- SE; n) were: normal mucosa 83.2 +/- 7.3; 25, adenomas 199.4 +/- 19.1; 40, carcinomas 1269.7 +/- 174.9; 40, inflammatory bowel disease 1210.7 +/- 247.1; 34. The arginase activity differs significantly in the adenoma-carcinoma sequence according to the Duncan's test (p < 0.05).