Expression of glucose transporter and glucose uptake in human oocytes and preimplantation embryos.

The expression of glucose transporters 1, 2, 3 and 4 was evaluated in human oocytes and polyploid preimplantation embryos. Only glucose transporter 1 (GLUT-1) isoform was detected in oocytes and in 2-12-cell stage embryos. Glucose uptake was markedly increased in embryos as compared to oocytes (19.7 +/- 3.4 pmol/min/embryo and 2.3 +/- 0.3 pmol/min/oocyte), and GLUT-1 was inhibited by cytochalasin B. These results suggest that, although GLUT-1 is expressed in human oocytes and throughout preimplantation development, its function in mediating the rise in glucose uptake is triggered following fertilization.