Conjugation and excretion of phenoltetrabromphthalein mono-, di-, and tetrasulfonates

¹ Department of Medicine, New York University School of Medicine, New York City

Phenoltetrabromphthalein monosulfonate and tetrasulfonate were administered to rats. The disappearance from plasma and excretion into bile was determined and compared to sulfobromophthalein. Spectrophotometric, paper-chromatographic, and electrophoretic methods of analysis were used for detection of the compounds and their derivatives. The monosulfonate disappeared rapidly from plasma and was excreted in bile as glutathione and glutathione-glucuronide derivatives. The tetrasulfonate disappeared slowly from plasma and was excreted in bile apparently unchanged. The tetrasulfonate reacted chemically with glutathione but the reaction was not enzymatically catalyzed in vitro. It is concluded that the number of sulfonate groups on the phenoltetrabromphthalein molecule are important determinants of hepatic conjugation and excretion.

Key Words: hepatic conjugation • sulfobromphthalein-related compounds • phenoltetrabromphthalein sulfonates • biliary excretion • glucuronide conjugation • glutathione conjugation • glutathione-conjugating enzyme

Submitted on May 27, 1964