Figure 5.

Effect of different concentrations of ouabain on Na⁺-K⁺-ATPase α-subunit mRNA expression in HUVECs. The expression level of α₁-subunit mRNA increased after 0.3 nM ouabain treatment (1.78 ± 0.61 versus 1, P < 0.01) and decreased after 1.8 nM ouabain treatment (0.62 ± 0.41 versus 1, P < 0.01). However, α₂- and α₃-subunit mRNA expression decreased after 0.3 nM ouabain treatment (0.73 ± 0.31 and 0.61 ± 0.42 versus 1, respectively; P < 0.01) and increased after 1.8 nM ouabain treatment (1.27 ± 0.39 and 1.87 ± 0.50 versus 1, respectively; P < 0.01). Values shown indicate means ± SEM of three observations assayed in triplicate. In each α-subunit group, bars not sharing a common letter are significantly different from each other (P < 0.01).