Human and rat beta cells differ in glucose transporter but not in glucokinase gene expression.

A De Vos, H Heimberg, E Quartier… - The Journal of …, 1995 - Am Soc Clin Investig
A De Vos, H Heimberg, E Quartier, P Huypens, L Bouwens, D Pipeleers, F Schuit
The Journal of clinical investigation, 1995Am Soc Clin Investig
Glucose homeostasis is controlled by a glucose sensor in pancreatic beta-cells. Studies on
rodent beta-cells have suggested a role for GLUT2 and glucokinase in this control function
and in mechanisms leading to diabetes. Little direct evidence exists so far to implicate these
two proteins in glucose recognition by human beta-cells. The present in vitro study
investigates the role of glucose transport and phosphorylation in beta-cell preparations from
nondiabetic human pancreata. Human beta-cells differ from rodent beta-cells in glucose …
Glucose homeostasis is controlled by a glucose sensor in pancreatic beta-cells. Studies on rodent beta-cells have suggested a role for GLUT2 and glucokinase in this control function and in mechanisms leading to diabetes. Little direct evidence exists so far to implicate these two proteins in glucose recognition by human beta-cells. The present in vitro study investigates the role of glucose transport and phosphorylation in beta-cell preparations from nondiabetic human pancreata. Human beta-cells differ from rodent beta-cells in glucose transporter gene expression (predominantly GLUT1 instead of GLUT2), explaining their low Km (3 mmol/liter) and low VMAX (3 mmol/min per liter) for 3-O-methyl glucose transport. The 100-fold lower GLUT2 abundance in human versus rat beta-cells is associated with a 10-fold slower uptake of alloxan, explaining their resistance to this rodent diabetogenic agent. Human and rat beta-cells exhibit comparable glucokinase expression with similar flux-generating influence on total glucose utilization. These data underline the importance of glucokinase but not of GLUT2 in the glucose sensor of human beta-cells.
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The Journal of Clinical Investigation