Liver blood flow measured by indocyanine green in conscious unrestrained miniature pigs

For studies in physiology and biochemistry of the liver the measurement of hepatic blood flow is a fundamental precondition. Therefore, the least invasive method, the measurement of liver blood flow by indocyanine green (ICG) dye elimination, was re-evaluated for the miniature pig, an animal model of increasing interest. The accuracy of spectrophotometric determination of ICG was enhanced by addition of 5% of desoxycholic acid. It was shown that ICG was eliminated exclusively by the liver. An extraction rate of 30%-50% was found in mini-pigs, but an insufficient rate of 5%-10% in pigs of German landrace. A liver blood flow ranging from 70 to 160 ml/100 g X min-1 was measured. These values are in good accordance with datas from simultaneous estimation of blood flow by 133Xenon washout. As shown for a starvation/refeeding cycle, liver blood flow measurement by ICG combined with permanently implanted catheters is a practicable tool for studies of the metabolic and pharmacologic fate of substances resorbed from the gut.