Glucose transporter GLUT1 mRNA expression in the ontogeny of glucose incorporation in mouse preimplantation embryos.

Glucose incorporation and utilization in mouse embryos increases during preimplantation development. A reverse transcription-polymerase chain reaction (RT-PCR) was applied to quantitatively determine the levels of glucose transporter GLUT1 mRNA in preimplantation mouse embryos. The levels of GLUT1 mRNA increased during embryonic development, and it was 11-fold greater in blastocysts than in 2-cell embryos. Similar increases were observed in glucose incorporation as measured by 2-deoxyglucose uptake in the embryos. Increases in GLUT1 mRNA and glucose uptake are also observed when 2-cell embryos are developed to blastocysts in vitro, although the levels are one-third to half of those of the in vivo blastocysts. These results suggest that glucose incorporation during preimplantation development depends at least in part on the expression of GLUT1 mRNA transcription, which results in increased amounts of GLUT1 protein and that the difference in its expression in vivo and in vitro may serve as a clue for studying the preimplantation development of embryos.