AJP - Renal Physiology, Vol 250, Issue 6 1039-F1045, Copyright © 1986 by American Physiological Society
Effect of respiratory acidosis on intracellular pH of the proximal tubule
B. Trivedi and R. L. Tannen
In contrast to chronic metabolic acidosis, chronic respiratory acidosis
does not result in an adaptation in either renal ammonia or glucose
production. To examine the possibility that this might be explained by a
difference in proximal tubule intracellular pH, the response of two
pH-sensitive metabolites, citrate and alpha-ketoglutarate, were assessed.
Metabolic acidosis of 3 days duration, induced by drinking 1.5% NH4Cl,
significantly reduced urinary citrate excretion (172 to 15 mumol/day) and
renal cortical citrate (1.33 to 0.88 mumol/g) and alpha-ketoglutarate (0.90
to 0.46 mumol/g) concentrations in comparison with normal rats. Chronic
respiratory acidosis, produced by 3 days in a 10% CO2 environment, lowered
systemic pH similar to metabolic acidosis but had no effect on either
urinary citrate excretion or renal cortical citrate and alpha-ketoglutarate
concentrations. By contrast, acute respiratory acidosis (3, 6, or 24 h
duration) reduced urinary citrate excretion and renal cortical citrate and
alpha-ketoglutarate concentrations in a fashion similar to acute metabolic
acidosis. These data suggest that acute acidosis of either respiratory or
metabolic origin lowers the intracellular pH of the proximal tubule.
However, when the acid-base abnormality enters the chronic phase, proximal
tubular intracellular pH remains low with metabolic acidosis but returns to
normal values with respiratory acidosis.(ABSTRACT TRUNCATED AT 250 WORDS)
