Co-administration of 200 mg/kg/day metformin with 100 mg/kg/day L-A, 0.25 mg/kg/day ZnPP, 5 mg/kg/day DL-PAG or 10 mg/kg/day CQ i.p. for 6 successive days before induction of ischemia and promptly at the onset of reperfusion to rats significantly raised the hepatic nitrite level (Fig. 4A) and significantly lowered the hepatic HO-1 (Fig. 4B) and H2S (Fig. 4C) levels as compared to animals treated with metformin only. This evidence concerns the gene HMOX1 and ischemia.