Effect of nutritional status on organic anion clearance by the swine liver

Hepatic dysfunction follows a wide range of insults. Impaired excretion of organic dyes such as bilirubin often occurs before other obvious clinical defects in metabolic processes. Indocyanine green (ICG) is excreted through pathways similar to those of bilirubin. To determine the effectiveness of ICG as a marker of hepatic dysfunction related to clinical malnutrition, pigs received 5 mg/kg ICG with simultaneous sampling from the hepatic vein, pulmonary artery, and aorta over 3 hours. Group I remained well nourished, group II was fasted to a weight loss equal to 20% of initial body weight, and group III was fasted to a 20% weight loss and then refed until the animals regained their initial weight. Both systemic and intrinsic hepatic clearance were depressed significantly with fasting but returned above baseline after refeeding. No significant difference appeared between systemic and intrinsic hepatic clearance. Extraction ratios were low in all groups. In outbred swine, ICG clearance reflects the function of hepatic organic anion excretion in vivo, and venous sampling reflects intrinsic hepatic clearance. The impairment of the carrier-mediated transport system is reversible with refeeding.