Representative histological images of the insulin-immunoreactive cells in the pancreas, taken from intact normoglycemic or db/db mice. (A) Intact control mouse; (B) db control mouse; (C) metformin 250 mg/kg treated db mouse; (D) GT 400 mg/kg treated db mouse; (E) fGT 400 mg/kg treated db mouse; (F) fGT 200 mg/kg treated db mouse; (G) fGT 100 mg/kg treated db mouse. GT, Green tea aqueous lyophilized extracts; fGT, Aquilariae Lignum-fermented green tea aqueous lyophilized extracts; IS, pancreatic islet; PD, pancreatic secretory duct. All immunostained by avidin-biotin-peroxidase complex. Scale bars = 80 µm.