Analyzing the expression of FGF21 and GDF15 genes in tissues as well as the level of FGF21 in plasma, we have confirmed the role of FGF21 in diabetes induction/maintenance, but this mitokine is not essential for the effect of MitoTam, since there was no change in its expression after treatment despite improved diabetic parameters observed in treated animals (Supplementary Fig. 7). This evidence concerns the gene FGF21 and diabetes mellitus.