IMMUNOHISTOCHEMICAL DETECTION OF GAMMA-GLUTAMYL-TRANSPEPTIDASE IN NORMAL HUMAN TISSUE

We developed a new, highly specific antibody that localizes gamma-glut amyl transpeptidase (GGT) in formalin-fixed sections of human tissue. The specificity of the antibody, GGT129, is demonstrated by Immunostai ned Western blots of whole cell homogenate from five different tissues . The utility of the antibody is shown by a comprehensive study of GGT expression in normal human tissue. This study reveals GGT expression for the first time in a number of tissues, including glands in the end ocervix, endometrium, and adrenals. Strong immunoreactivity was observ ed on the surface of renal proximal tubule cells, hepatic bile canalic uli, and capillary endothelial cells within the nervous system. Secret ory or absorptive cells in sweat glands, prostate, salivary gland duct s, bile ducts, pancreatic acini, intestinal crypts, and testicular tub ules were also GGT-positive. Small bands of positively stained stromal cells and GGT-positive histiocytes were seen in some tissues. Analysi s of human fetal tissue shows that the developmental expression of GGT differs in humans and rodents. These findings form the basis for furt her work on GGT induction in tumors and the effect of GGT expression o n the response of tumors to chemotherapy.