The alteration of renal deposition of mercury (Hg) after mercury vapor (Hg0) exposure was studied in mice pretreated with acivicin, a potent and irreversible inhibitor of gamma-glutamyltranspeptidase (GGT). Pretreatment with acivicin decreased renal Hg concentration by about 60% and significantly increased Hg concentration in the urine compared with the non-treated group. The results suggest that renal deposition of Hg after Hg0 exposure depends on renal GGT, which plays an important role in the uptake of GSH or GSH conjugates filtered through the glomeruli. It seems that the mechanism of renal Hg deposition after Hg0 exposure is similar to that after exposure to ionic Hg: a GGT-mediated incorporation of an Hg-GSH complex into renal tubular cells. The acivicin pretreatment after Hg0 exposure did not affect Hg concentrations in the liver and erythrocytes.