The intestinal diamine oxidase activity under the influence of adaptive proliferation of the intestinal mucosa--a proliferation terminating principle?

Under clinical conditions, intestinal mucosal hyperproliferation together with a reduced diamine oxidase (DAO) activity was found in inflammatory and neoplastic diseases. Therefore, we studied the influence on DAO activity of a regulated mucosal proliferation as obtained following partial small bowel resection in a rat model. A statistically significant, more than 4-fold elevation of the enzymic activity was observed during the first days after partial resection. At the peak of mucosal proliferation (8th. postoperative day) the DAO activity was significantly reduced by about 50% of the initial value. We suggest that the DAO may be involved in a negative feed-back control mechanism of mucosal proliferation.