Distribution and binding of [14C]acrylamide to macromolecules in SENCAR and BALB/c mice following oral and topical administration.

To determine if differences in acrylamide distribution or its binding to DNA could be responsible for the reported higher incidence of skin papillomas observed after oral administration compared to topical application, [14C]acrylamide was administered by topical application and oral intubation to male SENCAR and BALB/mice. Portions of lung, liver, stomach, testes, and skin were removed, and 14C was measured at 15 min, 30 min, 1, 6, 12, 24, and 48 hr. Binding to DNA, RNA, and protein was measured at 6 and 48 hr. Following oral administration, few strain differences in distribution or binding were noted. After topical application, SENCAR mice generally showed higher tissue concentrations than did the BALB/c mice at the early time periods but not at the later ones. Comparing the two routes, comparable concentrations were observed in all tissues except the skin where the amount of [14C]acrylamide after topical application was approximately 100 times that observed after oral administration. At 48 hr, binding to DNA was sevenfold higher after topical than after oral administration. The effect of route on papilloma formation cannot be explained, therefore, on the basis of either a difference in distribution or binding to DNA in the target organ. The binding of acrylamide to DNA in skin was similar in both SENCAR and BALB/c mice indicating that the much greater susceptibility of the SENCAR mice to tumorigenesis cannot be explained simply on the basis of distribution or macromolecular binding.