Intestinal metaplasia and altered enzyme expression in propylnitrosamine-induced Syrian hamster cholangiocellular and gallbladder lesions

Intrahepatic bile duct and gallbladder preneoplastic and neoplastic lesions induced in Syrian golden hamsters by propylnitrosamine treatment were investigated for the presence of polysaccharides and assayed immunohistochemically for expression of the enzymes glucose-6-phosphate dehydrogenase (G6PD) and glutathione-S-transferase (GST) molecular forms. On the basis of an increase in G6PD and the GST-placental form, a sequence of altered cell populations ranging from simple ductular proliferation through dysplasia and cholangiofibroma to cholangiocellular carcinoma could be established, the latter three lesions being characterized by marked increase in polysaccharide production. While similar goblet cell (intestinal) metaplasia and increased polysaccharide storage were also evident in carcinogen-induced gallbladder lesions G6PD and GST-P expression was decreased when compared with control epithelium.