- Coexpression of glucose transporters and glucokinase in Xenopus oocytes indicates that both glucose transport and phosphorylation determine glucose utilization. Morita, H., Yano, Y., Niswender, K.D., May, J.M., Whitesell, R.R., Wu, L., Printz, R.L., Granner, D.K., Magnuson, M.A., Powers, A.C. J. Clin. Invest. (1994)