Placental glucose transport and GLUT 1 expression in insulin-dependent diabetes

OBJECTIVE: Altered transport functions in the placenta might contribute to adverse outcome of pregnancies in women with diabetes. Therefore we studied placental glucose transport in this pregnancy complication. STUDY DESIGN: Syncytiotrophoblast microvillous membrane vesicles and basal membrane Vesicles were isolated from women with uneventful pregnancies (control subjects, n = 21) and from women with pregnancies complicated by insulin-dependent diabetes mellitus, White class D (n = 7). Glucose uptake and GLUT 1 (glucose transporter 1) expression were studied by means of radiolabeled tracers and Western blot, respectively. RESULTS: In the group with insulin-dependent diabetes mellitus, Values for hemoglobin A(1C) were moderately elevated in the first trimester (6.61 +/- 0.35) but not later in pregnancy and 4 of the 7 neonates were large for gestational age. In the basal membrane vesicles, insulin-dependent diabetes mellitus was associated with a 40% increase in GLUT 1 expression and a 59% higher mediated uptake of D-glucose. No alterations could be demonstrated in microvillus membrane vesicles. CONCLUSION: Placental glucose transport capacity appears to be increased in insulin-dependent diabetes mellitus. These alterations might explain the occurrence of macrosomia despite well-controlled diabetes.