This study is robust for its use of an adult mammal model of obesity and TD2x (with a sample size sufficient to detect statistical differences for both in vivo and in vitro parameters), its use of long-term metformin treatment, and its state-of-the art photolabeled biotinylation technique to assess GLUT trafficking in the lung. Here, SLC2A1 is linked to obesity due to melanocortin 4 receptor deficiency.