OBJECTIVE: Resistin was thought to link the obesity to type 2 diabetes. This study aimed to investigate the effect of resistin on insulinoma cell proliferation. METHODS: pcDNA3.1-resistin was transfected into rat insulinoma cells RINm5F. Cell proliferation was assessed by the MTT assay. The resistin and SOCS3 mRNA levels were assessed by RT-PCR. The total Akt level and the phosphorylation status were assessed by Western blot. RESULTS: The over-expressed resistin inhibited the RINm5F cell proliferation (P<0.05). SOCS-3 expression was up-regulated by resistin over-expression (3.2 folds over the control; P<0.05). Akt phosphorylation was down-regulated by resistin over-expression (0.6 fold over the control; P<0.05). CONCLUSIONS: Resistin impairs the rat insulinoma cell RINm5F proliferation. This might be attributed to a down-regulation of Akt level caused by increased SOCS-3 expression.[Chin J Contemp Pediatr, 2010, 12 (1):43-46]