Release of lactate by the liver in metabolic acidosis in vivo.

Chronic metabolic acidosis was induced in dogs by HCl. Pyruvate and lactate production and extractions were studied by arteriovenous sampling and electromagnetic flow probe measurements of gut and hepatic blood flows. The following results were obtained: (1) In control, overnight-fasted dogs, no net lactate or pyruvate was extracted by the liver. (2) In chronic acidosis, large amounts of lactate were produced. (3) Reduced tissue pyruvate levels and reduced activity of pyruvate dehydrogenase were found in the liver of these dogs compared with normal. These results demonstrate an unexpected effect of acidosis on hepatic lactate metabolism.