High-salt diet upregulates activity and mRNA of renal Na(+)-K(+)-ATPase in Dahl salt-sensitive rats.
We examined the effect of a high-salt (HS) diet on the regulation of renal cortical Na(+)-K(+)-adenosinetriphosphatase (Na(+)-K(+)-ATPase) in young Dahl salt-sensitive (DS) and salt-resistant (DR) rats. The activity of Na(+)-K(+)-ATPase, determined in permeabilized proximal tubule segments, was similar in DS and DR rats on normal salt (NS) diet. HS diet resulted in a twofold increase in proximal tubule Na(+)-K(+)-ATPase activity in DS rats but not in DR rats. The mRNA abundance, which was also similar in DS and DR rats on NS diet, increased after 2 days on HS diet in both innervated and denervated kidneys from DS rats but had no effect in DR rats. The activity of Na(+)-K(+)-ATPase and the content of alpha 1- and beta-protein in cortical homogenate were similar in DS and DR rats on both NS and HS diets. Treatment with benserazide, an inhibitor of dopa decarboxylase, upregulated proximal tubule Na(+)-K(+)-ATPase activity and increased Na(+)-K(+)-ATPase mRNA in DR rats on HS diet. Taken together, these data indicate that there is a primary defect in the dynamic hormonal regulation of Na(+)-K(+)-ATPase activity in intact tubular cells, which might stimulate Na(+)-K(+)-ATPase transcription.
Department of Pediatrics, St. Göran's Children's Hospital, Karolinska Institute, Stockholm, Sweden.
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Nishi
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Celsi
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Aperia
D000818:Animals; D015153:Blotting, Western; D003714:Denervation; D007668:Kidney / Q000294:innervation; D007672:Kidney Cortex / Q000201:enzymology*; D007687:Kidney Tubules, Proximal / Q000201:enzymology; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012982:Sodium, Dietary / Q000008:administration & dosage*; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics* / Q000378:metabolism
D012333:RNA, Messenger; D012982:Sodium, Dietary; D000254:Sodium-Potassium-Exchanging ATPase