Fig. 3
FGF21 is required for the accumulation of SAT mass in diet-induced obesity. Eight-week-old, male FGF21KO and WT littermates were fed with STC or HFD for 16 weeks (n = 10–12). a, b Body weight (a) and fat mass were measured once every 2 weeks (b). c Depot mass of SAT, epiVAT, periVAT and interscapular BAT depots in FGF21KO and WT mice fed with HFD. d Serum FGF21 levels at feeding state in WT mice during STC or HFD induction were measured by ELISA. e Schematic diagram of rmFGF21 replenishing strategy. After 8-week HFD induction, FGF21KO mice were randomly divided into FGF21KO + rmFGF21 group (0.1 mg kg−1 day−1 rmFGF21 by osmotic pump to mimic HFD-induced circulating FGF21 level) and FGF21KO + Vehicle group (receiving saline by osmotic pump) for another 4 weeks. The WT group also received continuous infusion of saline. n = 6. These results were reproduced in four independent experiments. f Serum FGF21 levels in FGF21KO + rmFGF21 group during the intervention. g Effect of physiologically-relevant dose of rmFGF21 administration on subcutaneous and visceral fat mass. Representative photographs of body appearance, subcutaneous fat and dissected SAT, visceral fat and dissected epiVAT from three groups. h Depot mass of SAT, epiVAT, periVAT and BAT depots in three groups. i H&E staining on paraffin sections from SAT in three groups. Scale bar = 50 μm. Cell size profiling of adipocytes from SAT was compared among three groups. The values show % from the total number of analyzed cells. Data are presented as mean ± s.e.m. Significance was determined by student’s t test (c, d), one-way ANOVA (h, i) and two-way ANOVA with Bonferroni multiple-comparison analysis (a, b). * or # P < 0.05, **P < 0.01, ***P < 0.001
