Figure 1.

In vitro N-acetyltransferase catalytic activities towards INH (A) and N-(4-aminobenzoyl)-L-glutamic acid (B) in cryopreserved human hepatocytes. Individual data points represent different human hepatocyte samples. Error bars illustrate mean ± S.E.M. in rapid, intermediate, and slow acetylators (n = 5). INH N-acetyltransferase activities differed significantly (P < 0.005) between rapid, intermediate, and slow acetylators (rapid vs. intermediate P < 0.05; rapid vs. slow P < 0.01) whereas N-(4-aminobenzoyl)-L-glutamic acid N-acetyltransferase activities did not (P > 0.05).