HEPATIC ANION FLUX DURING ACUTE ENDOTOXEMIA

We sought to determine the role the liver might play in the regulation of anion-cation balance during both stable baseline conditions and ac ute endotoxemia. Ten pentobarbital sodium-anesthetized dogs were instr umented at laparotomy with ultrasonic flow probes around the left rena l artery, portal vein, and hepatic artery, and catheters were inserted into the hepatic vein, portal vein, pulmonary artery, left renal vein , and abdominal aorta. Measurements were obtained from each site at ba seline and 30-45 min after the intravenous infusion of endotoxin. The total anion flux across the liver was calculated from the strong-ion d ifference. At baseline, the Liver removed anions from the circulation (-0.34 meq/min). With early endotoxemia, however, the liver switched t o the release of anions (0.12 meq/min; P = 0.0046). After endotoxin ad ministration, the gut, which was neutral at baseline, began to take up anions (-0.47 meq/min; P = 0.008). Anion flux across the lung and kid ney was unchanged. We conclude that in the dog the liver, which remove s anions at baseline, switches to release anions during early endotoxe mia and may be a major site of acid production in early sepsis.