With no difference in physical activity and food intake, we assumed that enhanced thermogenesis might contribute to the increased energy expenditure in FoxO1 KODAT mice. Since sympathetic nervous system plays a crucial role in control of adaptive thermogenesis23, we first checked serum level of norepinephrine in FoxO1 KODAT mice. As expected, serum norepinephrine level of KO mice was significantly elevated suggesting the increment of sympathetic nervous system in FoxO1 KODAT (Fig. 6a and Supplementary Fig. 4b). Interestingly, we also observed an elevation in dopamine contents in midbrain and SN of the KO mice (Fig. 6b).
