Renal gamma-glutamyltranspeptidase: In situ antiluminal localization.
Renal localization of gamma-glutamyltranspeptidase was studied in functioning kidneys perfused with the gamma-glutamyl substrates, gamma-glutamyl-p-nitroanilide and N(gamma-L-glutamyl) 2-naphthylamide. In kidneys perfused with gamma-glutamyl-p-nitroanilide, 90% of the breakdown products appear in the blood (perfusate) rather than urine. The addition of the acceptor substrate glycylglycine to the perfusate stimulated gamma-glutamyl-p-nitroanilide breakdown 3-fold, both on the blood and urine sides, while the appearance of gamma-glutamylglycylglycine confirmed that the activity responsible stems indeed from gamma-glutamyltranspeptidase. Ureter ligation reduced the glomerular filtration rate to less than 10% of the control, while the breakdown of gamma-glutamyl-p-nitroanilide decreased only 5%. Kidneys perfused with N(gamma-L-glutamyl) 2-naphthylamide and the diazonium salt demonstrated staining of the glomeruli; isolated glomeruli and microvessels gave heavy staining when incubated with the histochemical substrates. These results demonstrate the association of a significant portion of the total renal gamma-glutamyltranspeptidase activity with the microvascular compartment.
D000818:Animals; D006651:Histocytochemistry; D007668:Kidney / Q000201:enzymology*; D007678:Kidney Glomerulus / Q000201:enzymology; D008297:Male; D008833:Microcirculation / Q000201:enzymology; D051381:Rats; D011919:Rats, Inbred Strains; D005723:gamma-Glutamyltransferase / Q000032:analysis*
D005723:gamma-Glutamyltransferase