Enzyme Activity Assay: The potency of compounds of formula I against the stearoyl-CoA desaturase was determined by measuring the conversion of radiolabeled stearoyl-CoA to oleoyl-CoA using rat liver microsome or human SCD1 following previously published procedures with some modifications (Joshi, et al., J. Lipid Res., 18: 32-36 (1977); Talamo, et al., Anal. Biochem, 29: 300-304 (1969)). Liver microsome was prepared from male Wistar or Sprague Dawley rats on a high carbohydrate diet for 3 days (LabDiet #5803, Purina). The livers were homogenized (1:10 w/v) in a buffer containing 250 mM sucrose, 1 mM EDTA, 5 mM DTT and 50 mM Tris-HCl (pH 7.5). After a 100,000xg centrifugation for 60 min, the liver microsome pellet was suspended in a buffer containing 100 mM sodium phosphate, 20% glycerol, 2 mM DTT, and stored at -78° C. Human SCD1 desaturase system was reconstituted using human SCD1 from a baculovirus/Sf9 expression system, cytochrome B5 and cytochrome B5 reductase.