Enhanced glucose metabolism and impaired placental function in hypoxic pregnant rats

Glucose metabolism using 2-deoxy-2-[18F]fluoro-D-glucose [( 18F]FDG) was studied in experimental hypoxia (10% oxygen concentration) of pregnant rats with special attention given to the placental function. After an i.v. injection of [18F]FDG, the uptake of 18F increased with time in the maternal brain, placenta and fetus of control rats. In the hypoxic condition, the uptake in these tissues was enhanced significantly, especially in the maternal brain and fetal heart, brain and lungs. A double-label autoradiography with [18]FDG and [14C]iodoantipyrine [( 14C]IAP) was performed to elucidate changes of the placental function in the hypoxic condition. The [18F]FDG image revealed a higher accumulation in the maternal side of the placenta of a control pregnant rat than in its fetal side. [18F]FDG uptake increased in the fetal brain and heart of hypoxic rats. The [14C]IAP image demonstrated that in the control rat there was a clear border zone on the maternal side of the placenta with very low permeability into the fetus. On the other hand, a high and heterogenous accumulation in both placenta and fetal organs was shown in hypoxic rats. We interpret this data to suggest that in a hypoxic condition the function of the placenta as a barrier system is impaired.