Furthermore, the liraglutide treatment led to a significantly higher serum level of secreted FNDC5 derivative than the control as quantitated by the irisin ELISA assay (Figure 2H and Supplementary Figure S4), aligning well with the 50% increase of serum irisin in patients with T2D after the treatment of GLP-1RA exenatide for 12 weeks (Liu et al., 2016). Here, FNDC5 is linked to type 2 diabetes mellitus.