The GLUT3 Glucose Transporter Isoform Is Differentially Expressed within Human Placental Cell Types¹

Abstract

The cellular localization of GLUT3 messenger ribonucleic acid (mRNA) and protein was examined in human term placenta using a combination of methodologies. In situ hybridization indicated that GLUT3 mRNA was present in the trophoblast cell layer and in vascular endothelium with a heterogeneous distribution pattern. GLUT3 protein migrating at an apparent molecular mass of 49 kDa was detected by immunoblotting in membranes from whole placenta and endothelial cells derived from intraplacental microvessels, but not in isolated trophoblast cells. This cell-specific pattern of expression was confirmed by immunocytochemical studies showing a prominent localization of GLUT3 protein in vascular endothelium. These findings indicate a differential distribution of GLUT3 mRNA and protein in the human placenta. Based on its cell-specific distribution at the fetal interface, GLUT3 protein could be of cardinal importance in the transport of glucose from the placenta to the fetal circulation.

Endometrial Glucose Transporters in Health and Disease

“…GLUT3 (SLC2A3) is a high-affinity glucose transporter expressed in tissues with an intensive glucose metabolism, such as the brain, placenta, preimplantation embryos, sperm, and testes (Maher et al, 1992;Shepherd et al, 1992;Haber et al, 1993;Burant and Davidson, 1994;Boileau et al, 1995;Hauguel-de Mouzon et al, 1997;Pantaleon et al, 1997).…”

“…GLUT2 is found in the liver, kidney, and small intestine, and it is associated with the insulin-dependent glucose uptake (Mueckler and Thorens, 2013). The high-affinity transporter GLUT3 is abundant in the brain, testes, placenta, and other organs with an intensive glucose metabolism (Maher et al, 1992;Burant and Davidson, 1994;Boileau et al, 1995;Hauguel-de Mouzon et al, 1997). GLUT4 is an insulin-dependent transporter that regulates fast glucose uptake into skeletal and heart muscle cells, adipocytes, and placental cells (Bell et al, 1990;Mueckler, 1990;Xing et al, 1998).…”

Fetal Nutrition: How We Become What We Are

“…In humans, GLUT1 seems to be the predominant glucose transfer protein expressed in both the microvillous and the basal membrane, and therefore is probably responsible for ingress and egress of glucose molecules (73). A second isoform, GLUT3, has been localized to the fetal capillary (74,75). Some caution, however, is in order.…”