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

Abstract

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. 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. In the group with insulin-dependent diabetes mellitus, values for hemoglobin A1c 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. 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.