Many arylamines (including carcinogens) and hydrazine drugs are acetylated by the cytosolic N-acetyltransferase (NAT). NAT plays an important role in the first step of arylamine metabolism and has been found in immortalized human cell lines, human and laboratory animal tissues. Human colon tumor cell line (colo 205) has also been shown to acetylate arylamine and possess NAT activity. The purpose of this study was to determine whether or not N-ethylphenyl acetamide (EPA) could affect cell viability, DNA synthesis and N-acetylation of 2-aminofluorene (AF) in colo 205 cells. Acetylated and nonacetylated AF were determined by using high performance liquid chromatography. EPA displayed a dose-dependent inhibition of cytosolic and intact cells' NAT activity, inhibition of viablility and DNA synthesis. Time-course experiments showed that N-acetylation of AF measured from intact colo 205 cells was inhibited by EPA for up to 48 h.
