We delineated and characterized the fetal hepatic glucose transporter in the rabbit. Employing the 2-deoxy-D-glucose displaceable 3H-cytochalasin B binding assay we estimated the number and Kd of the GT per mg of liver protein. A gradual increase in the number was observed during development, the fetus (23.8 +/- 2.04 pmoles/mg) expressing a lesser amount when compared to the neonate (59.5 +/- 17 pmoles/mg; p less than 0.05) and adult (142 +/- 11 pmoles/mg; p less than 0.05). On the other hand the affinity of the glucose transporter was higher in the fetus (Kd 287 +/- 81 nM) when compared to either the neonate (988 +/- 222 nM, p less than 0.05) or the adult (706 +/- 101 nM, p less than 0.05). We conclude that the fetal hepatic GT is more efficient secondary to a higher affinity for glucose.