syrian hamsters were given in a single dose of n-nitrosobis ( 2-oxopropyl ) -amine ( bop ) ( 40 mg/kg , s.c. ) and 1 week later were fed 1 of 4 retinoid types ( 13-cis-retinoic acid ( 13-cis-ra ) , n-ethylretinamide ( era ) , 2-hydroxyethylretinamide ( oh-era ) , or 4-hydroxyphenylretinamide ( pra ) ) each at 3 levels ( 0.05 , 0.1 , 0.2 mm/kg diet ) .
C0035339
retinoid
C0022265
13-cis-retinoic acid