FIG. 5.

Recombinant FGF21 increases energy expenditure and physical activity in DIO mice. Indirect calorimetry was conducted continuously for 19 days. DIO mice were injected intraperitonally with FGF21 at doses of 10 mg · kg⁻¹ · day⁻¹ (red open squares, n = 5) and 1 mg · kg⁻¹ · day⁻¹ (green filled circles, n = 6) or vehicle (blue open circles, n = 5). A: FGF21 treatment elevated O₂ consumption. Measurements were collected every 20 min, and each data point represents a rolling average of six time points. Dark periods (6:30 p.m. to 6:30 a.m.) are shown by a shaded gray box. Arrow marks first statistically significant difference between FGF21 10 mg · kg⁻¹ · day⁻¹ and vehicle. All data are means of multiple mice ± SE. Data shown are the first 7 days of the treatment. O₂ consumption (B), CO₂ production (C), physical activity (D), energy expenditure (E), and respiratory quotient (F) in the dark periods were monitored for the entire 19 days. Data in B–F represent the average from the whole dark period. All means are shown with SE.