Distribution of [14C]canthaxanthin and [14C]lycopene in rats and monkeys

The absorption and distribution of [14C]-canthaxanthin and [14C]lycopene were studied in rats and in rhesus monkeys following the oral administration of [14C]canthaxanthin or [14C]lycopene in olive oil supplemented with 1 mg alpha-tocopherol/mL. For canthaxanthin and lycopene, peak accumulation of radioactivity in plasma occurred between 4 and 8 h in rats and between 8 and 48 h in monkeys. In rats, the liver contained the largest amount of both kinds of radioactive pigments. In monkeys, with the exception of one stomach sample, liver was also the major depot organ for both canthaxanthin and lycopene. The other organs tested accumulated various amounts of pigment. No labeled metabolic products of either canthaxanthin or lycopene were found.