Distribution of gamma-glutamyl transpeptidase in human pancreas: immunohistochemical study with a monoclonal antibody.

We studied in detail the distribution pattern of gamma-glutamyl transpeptidase (gamma-GT) in human pancreas, using the immunoperoxidase technique and a monoclonal antibody to human kidney gamma-GT. Positive reaction was confined exclusively to the luminal surface of the centroacinar cells and the epithelia of the intercalated, intralobular, and interlobular ducts. The immunoreaction was stronger in the intercalated and intralobular ducts than in the interlobular ducts. The acinar cells did not show any reaction. The islets of Langerhans were heavily surrounded by the ducts, and normal islet cells showed no reaction. The course of the ducts, from the acinar lumina to the interlobular ducts, was delineated by using reaction sites positive for gamma-GT as markers. The courses of the ducts, which comprise the pathway for pancreatic juice, were found to vary widely in their connections with each other, especially between the intralobular and interlobular ducts. At least three separate routes could be identified.