Effects of four retinoids in N-nitrosobis(2-oxopropyl)amine-treated hamsters.

Four synthetic retinoids were evaluated with regard to chemo-prevention of pancreatic carcinomas in carcinogen-treated hamsters. Syrian golden hamsters were given two injections of N-nitrosobis(2-oxopropyl)amine (20 mg/kg) and then were fed retinoid-supplemented diets for 1 year. The incidence of pancreatic carcinomas was lower in six of eight retinoid-fed groups than in the control group, although the differences were not statistically significant. The lowest incidence was observed in groups fed N-(4-pivaloyloxyphenyl)retinamide and N-(2-hydroxypropyl)retinamide. Testicular atrophy with decreased spermatogenesis was noted in males fed N-(2-hydroxypropyl)retinamide, N-(3-hydroxypropyl)retinamide, and N-(2,3-dihydroxypropyl)retinamide.