Cell extracts were prepared from mature 3T3-L1 adipocytes cultured in the absence or presence of 0.3 nM TNF-α for 48 h. 3T3-L1 cell homogenates were preincubated for 30 min at 37°C in the presence of various concentrations of each inhibitor. Pargyline at 1 mM was also added in the assay to inhibit monoamine oxidase activity. Benzylamine (30 μM) was then added as substrate for 1 h. IC₅₀ values were obtained by computer analysis with the ENZFITTER program. ApparentK_i values of SSAO towards the different SSAO inhibitors were then calculated by the equation of Cheng and Prusoff. Results represent the mean ± S.E. of four separate experiments.