Fig 9.

Catalase reduced the monensin-induced increases of Na,K-ATPase activity (A, n = 4) and the cytosolic Na,K-ATPase α1-subunit protein abundance (B, n = 4). The Na,K-ATPase activity was measured by ouabain-sensitive release of inorganic phosphate, which reacted with malachite green and was quantified by increases in the absorption at A₆₃₀. Membranes were probed with antibodies against aldose reductase (AR, cytosolic marker) and cytochrome c oxidase subunit IV (COX4, mitochondrial marker) to show adequate separation of these two compartments and with actin antibody to show roughly equal loading. (*p < 0.05 vs Control, **p < 0.05 vs Monensin, Two-way ANOVA, n = 4).