AJP - Renal Physiology, Vol 243, Issue 3 227-F234, Copyright © 1982 by American Physiological Society
Immediate adaptation of the dog kidney to acute hypercapnia
A. Gougoux, P. Vinay, M. Cardoso, M. Duplain and G. Lemieux
Studies were performed to determine whether ammoniagenesis could adapt
instantaneously to acidosis in the dog kidney. Following acute respiratory
acidosis, renal glutamine extraction rose acutely in dogs with stable renal
blood flow but did not change when the renal blood flow fell by more than
25%. Acute hypercapnia immediately increased renal ammonia production in
both groups of dogs. The rate of both glutamine extraction and ammonia
production in acutely hypercapnic dogs without hemodynamic changes was
comparable to the rates observed in dogs with chronic metabolic acidosis.
Furthermore, the renal metabolite profile observed in acute hypercapnia was
similar to the pattern described in chronic metabolic acidosis, i.e., a
marked fall in renal glutamate and alpha-ketoglutarate concentrations and a
fivefold increase in malate and oxaloacetate concentrations. In the liver
and muscle, acute hypercapnia induced no significant change in glutamine
concentration but glutamate and alpha-ketoglutarate concentrations
decreased. Our findings demonstrate that the dog kidney can adapt
immediately to acidosis but that hemodynamic change may mask this
adaptation.
