Hepatic transport of indocyanine green in rats chronically intoxicated with carbon tetrachloride

Abstract

Hepatic transport of indocyanine green (ICG) and probable factors altering the disposition of ICG were examined in rats chronically intoxicated with carbon tetrachloride. Delays were shown in both plasma disappearance and biliary excretion of ICG in intoxicated rats. No significant difference was shown in the total amount of ICG bound to the plasma proteins. In the intoxicated rats, significant decreases were observed in the pharmacokinetic parameters, k 12, k 34 and V 2, calculated by a three-compartment model, while a significant increase was observed in k 21; V 1 was not altered. In both the control and intoxicated rats, the values of k 12· V 1 were significantly smaller than the hepatic plasma flow, and it was suggested that the plasma flow does not play a primary role in the hepatic uptake of ICG. No significant difference was observed in the elution profiles of the 100,000 g supernatant fraction on a Sephadex G-75 column, and ICG bound mainly to the X-fraction in both the control and intoxicated rats. About 90 per cent of the ICG administered intravenously was distributed to the 9000 g precipitate fraction by 5 min in both groups of rats. It was concluded that a decrease in the permeability of the sinusoidal plasma membrane of the hepatocyte may explain the decrease of ICG uptake rate by the livers of the intoxicated rats.