The metabolism of 14C-cyclohexylamine in mice and two strains of rat.

After administration of 14C-cyclohexylamine (35-500 mg/kg) to male mice and rats, 80% of the dose of 14C was excreted in the urine, mostly within the first 24 h after dosing. In Wistar rats, 7-9% of the 14C in the 0-24 h urine was present as cis-4-aminocyclohexanol, with a similar amount as the corresponding 3-isomers. In the DA rat, only 1-2% of the 14C, and in mouse less than 1% of the 14C was present in the urine as aminocyclohexanols; unchanged cyclohexylamine accounted for about 95% of the activity. The extent of metabolism was not affected by either dose or route of administration. The species differences in metabolism may be implicated in the differences in toxicity during chronic high-dose administration.