Given data suggesting that 1) GLUT8 is localized to the hepatocyte cell surface and 2) GLUT8 mediates hepatocyte fructose uptake, fructose-induced de novo lipogenesis, and lipogenic gene induction, we examined GLUT8-deficient (GLUT8KO) mice to determine whether GLUT8 mediates fructose-induced hepatic steatosis in vivo. The gene discussed is SLC2A8; the disease is fatty liver disease.