SLC2A1 and hyperinsulinism: Next, the glucose transporter profile of these cells was examined; in both genotypes GLUT4 was significantly (p = 0.0011 for Sx16 knockout and p = 0.0006 for Sx16 wild type cells) downregulated in response to hyperinsulinemia whereas GLUT1 levels did not significantly change (Figures 5B–D).