Determination of liver intracellular pH in vivo and its homeostasis in acute acidosis and alkalosis.

An in vivo method is presented for the determination of liver intracellular pH (pHi) using [14C]dimethadione (DMO) in dogs. This method differs from those previously published in that hepatic venous and portal venous blood pH were selected as the extracellular reference pH, and liver blood space corrections are applied to whole liver tissue [14C]DMO activity. Using these corrections, a normal liver pHi of 6.99 +/- 0.03 (SE) was obtained. During acute metabolic acidosis and alkalosis, as well as during acute respiratory acidosis and alkalosis, the liver pHi remained normal; metabolic acidosis was 7.04 +/- 0.04; metabolic alkalosis was 6.92 +/- 0.08; respiratory acidosis was 6.98 +/- 0.04; and respiratory alkalosis was 7.00 +/- 0.10. None of these values was significantly different from normal (P greater than 0.05). Changes in intracellular bicarbonate and lactate appeared to account in part for the observed stability of the liver pHi despite acute manipulations resulting in a range of pH values between 7.09 and 7.63 in arterial blood.