Adrenal-dependent modulation of the catalytic subunit isoforms of the Na+-K+-ATPase in aorta.
Na+-K+-ATPase gene expression and activity were studied in aortas from adrenalectomized (ADX) rats and ADX rats with deoxycorticosterone supplement (ADX-DOCA). Northern analysis of RNA from ADX rats revealed a significant decrease in alpha2-mRNA levels (38.5 +/- 8.3% of control, P < 0.01) that was prevented by DOCA (P < 0.05). A decrease to 55.8 +/- 7.7% in alpha2-isoform protein was observed 8 days after adrenal removal (P < 0.05); DOCA reversed this effect (90.8 +/- 10.5%). Adrenalectomy induced a decrease of 68.5 +/- 4.5% in beta1-mRNA (P < 0.01) and 52.7 +/- 8.3% in ADX-DOCA rats (P < 0.01). Also, a reduction in beta1-isoform protein that was not prevented by DOCA was detected after adrenalectomy (47.1 +/- 11%, P < 0.01). In contrast, no differences in alpha1-mRNA or -protein levels were observed. Vascular sodium pump activity was reduced to 59.8 +/- 4.6% of control values after adrenalectomy (P < 0.01); this reduction was reversed by DOCA. Our data indicate that corticosteroids regulate Na+-K+-ATPase isoform expression and activity in vascular tissue in vivo, suggesting a mineralocorticoid-dependent modulation of alpha2-Na+-K+-ATPase gene expression in aorta, with beta1-isoform expression dependent on the presence of glucocorticoids.
Michea
L
L
Laboratory of Molecular and Cellular Physiology, School of Medicine, University Los Andes, Casilla 20106, Santiago 20-Chile.
Valenzuela
V
V
Bravo
I
I
Schuster
A
A
Marusic
E T
ET
D000305:Adrenal Cortex Hormones / Q000502:physiology; D000311:Adrenal Glands / Q000502:physiology*; D000315:Adrenalectomy; D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000201:enzymology*; D002384:Catalysis; D003900:Desoxycorticosterone / Q000494:pharmacology; D015870:Gene Expression / Q000502:physiology; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008297:Male; D009994:Osmolar Concentration; D051381:Rats; D017207:Rats, Sprague-Dawley; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics / Q000378:metabolism*
D000305:Adrenal Cortex Hormones; D007527:Isoenzymes; D003900:Desoxycorticosterone; D000254:Sodium-Potassium-Exchanging ATPase