On the other hand, expression of CREB-H-ΔTC in mouse models of obesity and diabetes has been shown to have beneficial effects, which are mediated in part through the activation of fibroblast growth factor 21 (FGF21), a hepatokine and a potential therapeutic agent for obesity-related medical conditions16, 18. Here, CREB1 is linked to obesity due to melanocortin 4 receptor deficiency.