Monoclonal antibodies against rat kidney γ-glutamyl transpeptidase show species and tissue specificity

Monoclonal antibodies have been raised against rat kidney gamma-glutamyl transpeptidase (GGT). All five antibodies immunoprecipitate enzyme activity from solubilized kidney brush-border membranes, but not from hepatocellular carcinoma membranes. Three of the antibodies react immunohistochemically with brush-border membranes in sections of adult rat kidney, but none of the antibodies cross-react with sections of guinea-pig, mouse or marmoset kidney or with untreated or carcinogen-treated rat liver. The antibodies do not recognize GGT in foetal-rat kidney and react poorly with kidney from 2-year-old rat. They do react with tubules trapped within mesenchymal kidney tumours induced by dimethylnitrosamine, but epithelial tumours, which are GGT-positive (although much less so than normal kidney), are not immunoreactive.