Figure 2.

Changes in the activities of membrane-linked ATPase (a) Na⁺K⁺ ATPase and (b) Ca²⁺ ATPase in liver mitochondria of 3, 12, and 24 months of control (C) and estradiol- (E2-) treated aging female rats. Each value is a mean ± SEM of five or more separate values from two to three experiments. The comparisons of experimental values are with the control values. Statistical significance: ^a P < 0.001, ^b P < 0.01 comparing age-matched controls versus E2 treatment and ^$ P < 0.001,*P < 0.05 versus 3 months.