The effects of 1 and 10 mg/kg of rmuFGF21 were assessed in WT and Tg mice. In WT mice, rmuFGF21 at 10 mg/kg reduced body weight (Figure 1A) but this effect was marginal in Tg mice (Figure 1B). Furthermore, rmuFGF21 reduced whole-body adipose mass (Figure 1C) and epididymal/inguinal fat pad mass (Figure S3A–B) in WT mice while no effects were observed in Tg mice. Lean mass, BAT, and liver weights were unaffected by rmuFGF21 in either WT or Tg mice (Figure 1D and Figure S3C–D). Blood glucose levels were unchanged in both WT and Tg mice following rmuFGF21 administration (Figure 1E), whereas rmuFGF21 reduced insulin levels (Figure 1F) and improved glucose tolerance in WT mice (Figures 1G and I). Despite the hyperinsulinemia in Tg mice, rmuFGF21 was ineffective in improving plasma insulin and glucose tolerance (Figures 1F, H–I). A minimal improvement in glucose tolerance was observed in Tg mice treated with 10 mg/kg rmuFGF21 (Figure 1H, 90 min.), but area under the curve (AUC) analysis did not reach statistical significance (Figure 1I).
