Sodium dependence of early distal H+ secretion in rat kidney.
In order to study the mechanism of H-ion secretion in cortical distal tubules of the rat kidney, the luminal pH and transepithelial potential difference (PD) were measured with double-barrelled, pH-sensitive, resin/reference microelectrodes. Perfusion of peritubular capillaries with low-sodium solutions increased luminal pH by 0.28 +/- 0.024 units. Perfusion of the lumen with 1 mM amiloride increased luminal pH by 0.67 +/- 0.01 units. These changes could not be attributed to modification of transepithelial PD. We conclude that early distal acidification is sodium-dependent, possibly owing to the presence of Na+/H+ exchange.
Lopes
M J
MJ
Departamento de Fisiologia e Biofisica, Universidade de São Paulo, Brasil.
Malnic
G
G
D000818:Animals; D006863:Hydrogen-Ion Concentration; D007684:Kidney Tubules / Q000502:physiology*; D007686:Kidney Tubules, Distal / Q000502:physiology*; D051381:Rats; D012964:Sodium / Q000378:metabolism*
D012964:Sodium