Evaluation of intestinal mucosal function by measuring expired (14)CO(2) after oral administration of (14)C-putrescine.

ABSTRACT

BACKGROUND: Diamine oxidase (DAO) is the enzyme that degrades putrescine, the key main product of polyamine metabolism, and reflects enterocytic maturity of absorption because diamine oxidase activity is highest in the small intestine. We have already shown that expired (14)CO(2) after oral administration of (14)C-putrescine correlated with intestinal DAO activity. However, the influence of food composition and the mucosal adaptation after intestinal resection have not been elucidated. METHODS: Male Wistar rats were fed normal chow or an elemental diet (ED) for 2 weeks. Resected rats underwent 50% jejunectomy or 50% ilectomy. Expired (14)CO(2) levels, following oral administration of (14)C-putrescine were measured in all rats, and compared with the intestinal DAO activity and other mucosal parameters. RESULTS: In the ED group, the (14)CO(2) levels reached a peak earlier, and values were 2.9-fold higher than in the group fed with normal chow. Mucosal alkaline phosphatase (ALP) and DAO activity in the ED group were also higher than in the group fed normal chow, although the mucosal wet weight was significantly lower in the ED group. In the resection groups, all expired (14)CO(2) values increased during measurement. The peak (14)CO(2) values in the jejunectomy group shifted earlier in the postoperative period. The mucosal DAO activity in both the resection groups was higher than it was in the control group at the fifth and 10th postoperative day. However, there were no differences among the three groups at the 15th postoperative day. CONCLUSIONS: Our studies suggested that expired (14)CO(2) after oral administration of (14)C-putrescine correlates with mucosal DAO activity, and that it also reflects intestinal function.