The metabolism of 2:4:5-trihydroxybutyrophenone in the rat and dog

Abstract

At the dose levels studied, 2,4,5-trihydroxybutyrophe-none is almost completely absorbed; about 75% of a single dose of 400 mg/kg in the rat, and 300 mg/kg in the dog, is excreted as conjugates, and the path of metabolism is largely by ethereal sulfate and glucuronide conjugation. The butyryl side chain appears to survive intact, and no evidence of oxidation to more complex phenols was obtained. Ethereal sulfate conjugation at the 5-hydroxyl group leads to 5-butyrl-2,4-dihydroxyphenyl hydrogen sulfate, isolated as its K salt. This was converted into 5-hydroxy-2,4-dimethoxybutyrophenone, and the synthesis of this substance is described. Glucuronic acid conjugation at the 4-hydroxyl group leads to 4-butyryl-2,5-dihydroxyphenyl glucosiduronic acid, which was not isolated but was converted into 4-hydroxy-2,5-dimethoxybutyrophenone. The isolation and synthesis of this substance is described. Dogs readily tolerate a daily dose level of 0.5 g/kg for 1 year, and rats a daily dose level of 1.5 g/kg for 2 years, with negligible storage of 2,4,5-trihydroxybutyrophenone in fat, liver, brain and kidneys.