Cellular localization of glucose transporter messenger RNA in human placenta.
High levels of expression of the glucose transporter (GLUT) isoforms 1 and 3 have been demonstrated in the human placenta by Northern blotting. However, the cellular localization of placental GLUT mRNA has not been described. Furthermore, recent preliminary kinetic data indicate that GLUT 2 might be present in syncytiotrophoblast. Human placental tissue from preterm (16-22 weeks) and term pregnancies was collected for identification and localization of glucose transporter mRNA. Following paraffin embedding, sections were cut and in situ hybridization was performed with fluorescein-labelled cRNA. In addition, immunoblotting and immunocytochemistry were carried out using an anti-GLUT 2 antibody. GLUT 1 mRNA was highly expressed in syncytiotrophoblast cells at term. GLUT 1 expression was much less abundant in non-syncytial cells. In contrast, GLUT 3 mRNA was present in lower amounts and more evenly distributed between syncytial and other placental cells. GLUT 1 mRNA was also highly abundant in preterm syncytiotrophoblast. The cellular distributions of GLUT 1 and GLUT 3 mRNA in the preterm placentas were similar to those in term tissue. With regard to GLUT 1, these findings correlate well with cellular localization and gestational development of GLUT 1 protein. No GLUT 2 protein was detected. It is concluded that GLUT 1 is the main isoform involved in transplacental glucose transport in the human.
Jansson
T
T
Department of Obstetrics, Gynecology & Reproductive Sciences, University of California, San Francisco, USA.
Cowley
E A
EA
Illsley
N P
NP
D005260:Female; D015870:Gene Expression; D051272:Glucose Transporter Type 1; D051273:Glucose Transporter Type 2; D051274:Glucose Transporter Type 3; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D009004:Monosaccharide Transport Proteins / Q000235:genetics*; D009419:Nerve Tissue Proteins; D010920:Placenta / Q000737:chemistry*; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis*; D014327:Trophoblasts / Q000737:chemistry
D051272:Glucose Transporter Type 1; D051273:Glucose Transporter Type 2; D051274:Glucose Transporter Type 3; D009004:Monosaccharide Transport Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; C495677:SLC2A1 protein, human; C495687:SLC2A3 protein, human