AIM To compare the effects of ouabain and
digoxin on both the systolic blood pressure (SBP) and
Sodium Pump', 1, 1599692)"; href="/tags/sodium-pump/">sodium pump α
subunit expression in the
pituitary of rats. METHODS Normal Sprague Dawley (SD) rats were injected with ouabain, digoxin and normal saline (NS), respectively, everyday and indirect SBP were recorded once a week. Six weeks later, all the rats were killed and sodium
Pump α 1 , α 2 , and α 3 subunit were detected in the pituitary with RT PCR method and immunohistochemical assay at mRNA and protein levels, respectively. RESULTS SBP of rats infused with ouabain increased significantly at the end of week 6 (132 6±9 0 vs 115 7±8 2 mmHg, P <0 01), while no difference of SBP was found between digoxin group and NS group. The effects of ouabain and digoxin on sodium pump α subunit isoform expression in pituitary were also different: At mRNA level, all the three isoforms of sodium pump
decreased in ouabain group but only α 3 subunit decreased in digoxin group. At protein level, the α 2 and α 3 subunit decreased and α 1 subunit unchanged in ouabain group, while the α 1 and α 3 subunit decreased and α 2 subunit unchanged in digoxin group. CONCLUSION Those results suggested that both ouabain and digoxin could regulate the sodium pump α subunit isoform expression, which might be related to the physiological roles of endogenous ouabain and responsible for the difference between the pharmacological and toxicological effects of ouabain and digoxin, including their effects on blood pressure.
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