Luminal secretion of ammonia in the mouse proximal tubule perfused in vitro.
AUTOR(ES)
Nagami, G T
RESUMO
A major portion of the total ammonia (tNH3 = NH3 + NH+4) produced by the isolated perfused mouse proximal tubule is secreted into the luminal fluid. To assess the role of Na+-H+ exchange in net tNH3 secretion, rates of net tNH3 secretion and tNH3 production were measured in proximal tubule segments perfused with control pH 7.4 Krebs-Ringer bicarbonate (KRB) buffer or with modified KRB buffers containing 10 mM sodium and 0.1 mM amiloride. Net tNH3 secretion was inhibited by 90% in proximal tubule segments perfused with the pH 7.4 modified KRB buffer while tNH3 production remained unaffected. The inhibition of net tNH3 secretion by perfusion with the modified KRB buffer was only partially reversed by acidifying the modified KRB luminal perfusate from 7.4 to as low as 6.2. These data indicate that the Na+-H+ exchanger facilitates a major portion of net tNH3 secretion by the proximal tubule and that luminal acidification may play only a partial role in the mechanism by which the Na+-H+ exchanger mediates net tNH3 secretion.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=442487Documentos Relacionados
- Effect of bath and luminal potassium concentration on ammonia production and secretion by mouse proximal tubules perfused in vitro.
- Regulation of ammonia production by mouse proximal tubules perfused in vitro. Effect of luminal perfusion.
- Effect of angiotensin II on ammonia production and secretion by mouse proximal tubules perfused in vitro.
- Ammonia production by isolated mouse proximal tubules perfused in vitro. Effect of metabolic acidosis.
- Inhibitory effects of volume expansion performed in vivo on transport in the isolated rabbit proximal tubule perfused in vitro.
