[Effects of maternal glucose loading on brain energy metabolism of fetal rats during hypoxia and recovery].

The effect of maternal infusions of hypertonic glucose on fetal brain carbohydrate metabolisms was investigated during the state of induced fetal hypoxia and its recovery using Wistar rats. Three milliliters of 20% glucose was injected into the pregnant rats and then the fetuses were delivered by hysterotomy after 20 minutes of induced hypoxia. The concentrations of glucose, lactate, ATP, ADP, AMP in fetal brain, and the levels of glucose and lactate in fetal blood were measured. The brain glucose concentrations in the loaded group was 3.9 times higher than that in the non-loaded group, and it decreased during hypoxia in both groups followed by a gradual increase in the recovery phase. Brain lactate levels were elevated during hypoxia in both groups, but the difference in the lactate levels was slight compared with the difference in the brain glucose levels in both groups. Brain ATP decreased by 21% in the glucose loaded group but 70% in the non-loaded group after hypoxia. The calculated brain energy charge potential [(ATP) + 0.5(ADP)]/[(ATP) + (ADP) + (AMP)] after hypoxia was 0.59 in the loaded group and 0.37 in the non-loaded group. This shows a high energy state in the brain of the glucose loaded group. It may be suggested that maternal glucose administration before and during fetal hypoxia does not cause remarkable lactate accumulation in the fetal brain, but serves to maintain a high intracellular energy state in the brain.