DISTRIBUTION OF 2-AMINOFLUORENE AND P-AMINOBENZOIC ACID N-ACETYLTRANFERASE ACTIVITY IN TISSUES OF C57BL 6J RAPID AND B6.A-NAT(S) SLOW ACETYLATOR CONGENIC MICE/

The distribution of N-acetyltransferase (NAT) activity in 35 tissues o f inbred rapid acetylator C57BL/6J and slow acetylator congenic B6.A-N at(s) mice was determined by incubation of tissue cytosols with 2-amin ofluorene or p-aminobenzoic acid followed by HPLC assay. Tissues exami ned included the gastrointestinal tract, lymphoid tissues, skin, blood components, and other major organs. NAT activity was found in all tis sues examined except blood plasma and seminal vesicles. Peyer's patche s had the highest activity with either substrate, and lymphoid tissue, in general, was high in NAT activity as was skin and much of the dige stive system. The acetylator polymorphism was apparent in most tissues for both p-aminobenzoic acid and 2-aminofluorene. The difference betw een rapid and slow acetylator phenotypes was usually greater with p-am inobenzoic acid than with 2-aminofluorene. The presence of NAT in the 33 tissues Of rapid and slow acetylator mice, as well as the absence o f NAT in plasma and seminal vesicles, was confirmed by immunoblots usi ng 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.