Tricycloquinazoline carcinogenesis: Interaction of carcinogen with mouse skin proteins

Abstract

AbstractFollowing topical application of tricycloquinazoline‐14C (0.03 μM) to mice, radioactivity was covalently bound to soluble and particulate skin proteins. The maximum level of binding to soluble proteins (equivalent to 4.2×10−6 μM TCQ/mg) was reached after 24 hours and that to particulate proteins (2.5×10−6 μM TCQ/mg) after 48 hours. These binding levels are lower than those observed with carcinogenic and non‐carcinogenic hydrocarbons studied under similar conditions. Treatment with doses of tricycloquinazoline greater than 0.03 μM did not produce increased levels of binding. The radioactivity associated with proteins was liberated following treatments (4 N KOH or 6 N HCl) which extensively degrade proteins. None of this radioactive material was identifiable as unchanged tricycloquinazoline. In the soluble proteins, radioactivity was bound almost exclusively to protein having the mobility of albumin whilst no significant radioactivity was associated with h proteins.