Characterization of Glucose Transporter 8 (GLUT8) in the Ovine Placenta of Normal and Growth Restricted Fetuses

Facilitated glucose transporters (GLUTs) in the chorionic epithelium are primary conduits for glucose delivery to placental and fetal tissues. The objective of this study was to characterize GLUT8 in the ovine placenta and determine if differences in mRNA and protein concentrations occur in an ovine model of intrauterine growth restriction (IUGR). A GLUT8 partial mRNA was generated, which shares 95 per cent identity with bovine GLUT8 nucleotide sequence. Northern hybridization identified a 2.1 kilobase transcript. GLUT8 mRNA concentrations normalized to β-actin mRNA concentrations increased during late gestation. Western immunoblots with an affinity-purified anti-mouse GLUT8 antiserum detected GLUT8 in late gestation ovine placenta plasma membranes. GLUT8 was immunolocalized to the chorionic epithelial layer and uterine epithelial cells from mid to late gestation. GLUT8 mRNA and protein concentrations at 135 days gestational age were decreased by 34.8 per cent and 21.8 per cent, respectively ( P