We next assessed glucagon sensitivity in glucagon tolerance tests (GLTT), because glucagon is a critical HGP‐stimulating hormone, and its sensitivity is increased in obesity.[10] Glucagon increased blood glucose to a significantly less degree in AAV8‐TBG‐Cre than in AAV8‐TBG‐GFP males (Figure 1I,J). Here, GCG is linked to obesity due to melanocortin 4 receptor deficiency.