Immunohistological localization of gamma-glutamyltranspeptidase in cerebellum at light and electron microscope levels.

An immune serum directed against the purified form of gamma-glutamyltranspeptidase from rat kidney cross-reacts with brain extract. An immunohistological study in rat cerebellum showed that the endothelial cells of blood vessels are heavily stained for the enzyme. Immunoelectron microscopy revealed high concentration of gamma-glutamyltranspeptidase on the luminal surface of cell membrane of endothelial cells, a possible site of the blood-brain barrier for amino acids.