SLC2A4 and type 2 diabetes mellitus: Although plasma concentrations of insulin and glucose did not differ between SAMP8 and SAMR1 mice, decreased levels of the glucose transporter GLUT4 and attenuated activation of Akt were observed in skeletal muscle of 6- and 9-month-old SAMP8 mice, pointing to peripheral insulin resistance, which is usually observed in patients with T2DM [50].