Sodium potassium ATPase activity in human rectal mucosa with and without renal insufficiency.
Studies in rats have shown that fecal potassium excretion and colonic mucosa Na-K-ATPase activity are elevated during dietary potassium loading and in chronic renal insufficiency. We studied Na-K-ATPase activity in human rectal mucosa in normal subjects as well as in patients with chronic renal insufficiency (creatinine clearance 2 to 72 mL/min). In normals, Na-K-ATPase activity was 4.34 +/- 0.83 mumol P/mg protein. After 2 weeks on a potassium intake of 300 mmol/d the mean activity did not differ significantly from the control value (2.49 +/- 1.30). In none of the patients with renal failure was Na-K-ATPase activity beyond the range found in the normal subjects, irrespective of serum potassium; the mean activity was 3.50 +/- 0.85. Like others, however, we found a two-fold increase in Na-K-ATPase activity in potassium loaded rats. Possible explanations for these differences are discussed.
Hené
R J
RJ
Boer
P
P
Koomans
H A
HA
Dorhout Mees
E J
EJ
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000450:Aldosterone / Q000097:blood; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase; D003404:Creatinine / Q000378:metabolism; D006801:Humans; D007413:Intestinal Mucosa / Q000201:enzymology*; D007676:Kidney Failure, Chronic / Q000201:enzymology*; D011188:Potassium / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012007:Rectum / Q000201:enzymology*; D012964:Sodium / Q000652:urine; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D000450:Aldosterone; D012964:Sodium; D003404:Creatinine; D000251:Adenosine Triphosphatases; D017301:Ca(2+) Mg(2+)-ATPase; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium