Binding of Hg2+, with HgCl2 as substrate, to basolateral membrane (BLM) vesicles from control and NPX rat kidney(s). Total membrane-associated Hg2+ was measured by incubating BLM vesicles with 1, 10, 20, 50, or 100 μM Hg2+ as the chloride salt and 203Hg2+, for up to 60 s in standard, 300 mOsmol/kg buffered sucrose solution. Binding of Hg2+ was determined by incubating BLM vesicles as above for 60 s in a buffered sucrose solution with an osmolarity of 1000 mOsmol/kg. Where indicated, samples were preincubated for 15 min with 0.25 mM acivicin. Results are expressed as nmol Hg2+/mg protein and are means ± SE of measurements from separate membrane vesicle preparations from three control and three NPX rats each. *Statistically significant difference (p < 0.05) from corresponding control sample. †Statistically significant difference (p < 0.05) from corresponding sample without acivicin.