Homocysteine (Hcy) inhibited rosiglitazone-induced differentiation of 3T3-L1 preadipocytes. 3T3-L1 preadipocytes were treated as indicated in Figure 5 except that Hcy (0, 0.05, 0.1 mmol/L) was added on D3. Hcy addition inhibited rosiglitazone-induced fat accumulation (a, b). However, with this protocol, the cell number was not affected by Hcy addition (a, c). Gene expressions of both peroxisome proliferator-activated receptor gamma (d) and adipocyte protein 2 (e) were inhibited. Data are means ± SD (n = 3). *P < 0.05 compared with the methylisobutylxanthine-dexamethasone-rosiglitazone (MDR)-induced Group (Rosi). Rosi, rosiglitazone. (A color version of this figure is available in the online journal)