Effect of clopidogrel administration on Li-induced polyuria and decrease in AQP2 protein abundance in rats. (A) Water intake; (B) urine output; (C) urine osmolality; and (D) electrolyte-free water clearance on the last day (day 13). CNT, control group; CLPD, clopidogrel-treated group; LI, Li-treated group; LI+CLPD, combined treatment with Li and clopidogrel. n=7 rats/group for (A), (B), and (C); n=4–5 rats for (D). *P<0.05 versus Li groups by ANOVA followed by Tukey–Kramer multiple comparison test [(A)–(D)]. (E) Representative immunoblot of AQP2 and β-actin proteins run with inner medullary tissue samples. (F) Densitometry of AQP2 protein bands in Li and Li+CLPD groups relative to β-actin protein bands; P value by Mann–Whitney nonparametric method.