IMMUNOHISTOCHEMICAL LOCALIZATION OF INSULIN-DEGRADING ENZYME ALONG THE RAT INTESTINE, IN THE HUMAN COLON ADENOCARCINOMA CELL-LINE (CACO-2),AND IN HUMAN ILEUM

Insulin-degrading enzyme (IDE) has been implicated in the intracellula r degradation oi insulin in insulin target cells. Knowledge of the exi stence oi this enzyme in the intestine will be beneficial to the achie vement of clinical oral efficacy of insulin. A comparative study was c onducted with rat intestine, human colon adenocarcinoma (Caco-2) cells , and human ileum. Confocal microscopy analysis using the anti-IDE ant ibody showed that IDE was localized in the mucosal cells of rat and hu man intestines, as well as in Caco-2 cells. Immunostaining of this enz yme was homogeneous throughout the cell excluding nucleus, indicating a typical cytosolic distribution in rat and human enterocytes and in C aco-2 cells.