Renal cortical tissues were harvested, lysed, and used for subsequent analyses. The activities of (A) extracellular signal-regulated kinases (ERK) 1/2, (B) c-Jun NH2-terminal kinases (JNK), (C) p38 MAPK, and (D) Big MAPK-1 (BMK1) were measured as described in Methods. All values were normalized by arbitrarily setting the densitometry of DS/L rats to 1.0. Densitometric analysis of the immunoreactive bands showed that a high salt diet markedly increased renal cortical ERK1/2, JNK, and BMK1 activities in DS rats, whereas p38 MAPK activity was unchanged. Candesartan (C) treatment significantly reduced ERK1/2, JNK, and BMK1 activities by -45%, -60%, and -70%, respectively, in DS-rats. On the other hand, no differences in the amounts of ERK1/2, JNK, p38 MAPK, and BMK1 were observed in samples by Western blotting analyses using pan-ERK1/2, JNK, p38 MAPK, and BMK1 (ERK5) antibodies (data not shown).