Abstract

The distribution of N-acetyltransferase (NAT) activity in 35 tissues of inbred rapid acetylator C57BL/6J and slow acetylator congenic B6.A-NatS mice was determined by incubation of tissue cytosols with 2-aminofluorene or p-aminobenzoic acid followed by HPLC assay. Tissues examined included the gastrointestinal tract, lymphoid tissues, skin, blood components, and other major organs. NAT activity was found in all tissues examined except blood plasma and seminal vesicles. Peyer's patches had the highest activity with either substrate, and lymphoid tissue, in general, was high in NAT activity as was skin and much of the digestive system. The acetylator polymorphism was apparent in most tissues for both p-aminobenzoic acid and 2-aminofluorene. The difference between rapid and slow acetylator phenotypes was usually greater with p-aminobenzoic acid than with 2-aminofluorene. The presence of NAT in the 33 tissues of rapid and slow acetylator mice, as well as the absence of NAT in plasma and seminal vesicles, was confirmed by immunoblots using an anti-NAT antibody raised in rabbits. These results indicate the widespread distribution of NAT activity and the relative abundance of extrahepatic N-acetylation capacity in the mouse.