SLC2A4 and diabetes mellitus: This increase in GLUT-4 content in epididymal adipose tissue would contribute, in part, to the improvement of whole-body glucose tolerance, because previous studies reported that diabetes decreases adipose GLUT-4 expression and impairs glucose tolerance [29] and revealed that quantitative alterations of adipose GLUT-4 levels alter whole-body glucose tolerance, such as skeletal muscle insulin resistance in transgenic mice [14,15,30].