Diamine Oxidase in Rat Small Bowel: Distribution in Different Segments and Cellular Location

: Diamine oxidase (DAO) is an enzyme with high activity found in the small bowel mucosa of the rat and man, and only with very low activity in all other tissues. The present study was designed to investigate the enzymatic distribution along 8 consecutive small bowel segments of mucosa and to test the DAO concentration on brush border membranes obtained from whole mucosal homogenate in Wistar rats. Our data document that DAO activity is mainly distributed in intermediate and distal small bowel segments and is not significantly associated with enterocyte brush border.