Human Renal Cortical and Medullary UDP- Glucuronosyltransferases (UGTs): Immunohistochemical Localization of UGT2B7 and UGT1A Enzymes and Kinetic Characterization of S-Naproxen Glucuronidation

Abstract

There is currently little information regarding the localization of UDP-glucuronosyltransferases (UGTs) in human renal cortex and medulla, and the functional contribution of renal UGTs to drug glucuronidation remains poorly defined. Using human kid-ney sections and human kidney cortical microsomes (HKCM) and human kidney medullary microsomes (HKMM), we com-bined immunohistochemistry to investigate UGT1A and UGT2B7 expression with in vitro microsomal studies to deter-mine the kinetics of S-naproxen acyl glucuronidation. With the exception of the glomerulus, Bowman’s capsule, and renal vasculature, UGT1A proteins and UGT2B7 were expressed throughout the proximal and distal convoluted tubules, the loops of Henle, and the collecting ducts. Additionally, UGT1A and UGT2B7 expression was demonstrated in the macul