OBJECTIVE Repetitive subcutaneous or intracerebroventricular administration of brain-derived neurotrophic factor (BDNF) ameliorates glucose metabolism and enhances energy expenditure in obese diabetic C57BL/KsJ-db/db mice. To explore the mechanism of action through which BDNF regulates glucose metabolism, we examined the effects of BDNF on glucose utilization and norepinephrine (NE) content in peripheral tissues of diabetic mice. METHODS [(14)C]2-deoxyglucose ([(14)C]2-DG) uptake into peripheral tissues was analysed after intravenous injection of [(14)C]2-DG in db/db and normal C57BL/6 mice, and [(14)C]2-DG uptake and NE content in peripheral tissues were analysed after subcutaneous administration of BDNF (20 mg/kg) to male db/db and normal mice for 8 days. RESULTS [(14)C]2-DG uptake in the diaphragm, heart, gastrocnemius, soleus and interscapular brown adipose tissue (BAT) of db/db mice was significantly lower than in normal mice. Repetitive administration of BDNF to db/db mice for 8 days enhanced [(14)C]2-DG uptake in the diaphragm, heart, soleus, BAT and liver. The NE content in heart, skeletal muscle, interscapular BAT and liver of db/db mice given BDNF was high compared with db/db mice given vehicle, whereas no significant change in NE content in peripheral tissues was observed in normal mice given BDNF and those given vehicle. BDNF did not affect [(14)C]2-DG uptake or NE content in the white adipose tissue of db/db mice. CONCLUSIONS These data indicate that BDNF ameliorates glucose metabolism by enhancement of glucose utilization in muscle and BAT, with this effect caused by modulation of the central and peripheral nervous systems.