Glucose transporter (Glut1, Glut3) mRNA in human placenta of diabetic and non-diabetic pregnancies

Transport of glucose into the cell is catalyzed by glucose transporters (Glut). Glut1 and Glut3 are expressed at various levels in many human tissues, including the placenta. It has been reported that ambient glucose can affect both glucose transport activity and expression of the Glut genes, and protein. To date, very few studies concerning Glut in the placenta have been published, and studies in vivo in human diabetic pregnancy are lacking. We therefore investigated placental Glut1 and Glut3 mRNA by Northern blot analysis in ten diabetic (five insulin dependent diabetes mellitus (IDDM), two non-insulin dependent diabetes mellitus (NIDDM) and three gestational diabetes mellitus (GDM)) and nine non-diabetic women. The quantitative results of specific mRNA/beta-actin ratios were expressed as arbitrary units. The results were evaluated according to metabolic and clinical findings. Glut1 and Glut3 mRNA values in diabetic and non-diabetic pregnant women were similar. The metabolic environment seems to affect the Glut3 mRNA levels in IDDM pregnant women but not the control women. In addition, Glut3 mRNA decreased in late pregnancy in the diabetic but not in the control women. Moreover, Glut1 mRNA levels were correlated with maternal age in the diabetic as well as in the control women (significantly). Finally, an inverse correlation was found between Glut1 mRNA levels and placental weight (in both diabetic and non-diabetic women). These results, although preliminary, shed some light on the function of these glucose transporters in normal as well as in diabetic pregnancies and prompt us to carry out a further investigation to better elucidate fetomaternal metabolic correlation at the placental level.