Glucose transporter expression is developmentally regulated in in vitro derived bovine preimplantation embryos

Glucose is readily been taken up and utilized by preimplantation embryos fr om different species, However, a comprehensive analysis of the glucose tran sporter expression throughout preimplantation development is still missing. Here, we have investigated the expression of facilitative glucose transpor ters (Glut1-5 and 8) and sodium-dependent-glucose transporter (SGLT-I) in b ovine oocytes and preimplantation embryos up to d16 of development, using R T-PCR and immunohistochemistry. The embryos were produced in vitro by IVM-I VF. Glut1, Glut3, Glut8, and SGLT-I were expressed in all stages studied. G lut4 transcripts were first detected at the blastocyst stage. Glut2 express ion was restricted to the period of blastocyst elongation at d14 and d16. T ranscription of the fructose transporter Glut5 started at the 8-/16-cell st age. Our results show a distinct expression pattern for glucose transporter s during bovine embryo development in vitro indicating specialized function s for these isoforms at different developmental stages in bovine embryos. ( C) 2001 Wiley-Liss, Inc.