Glucose uptake, utilization, and transfer by the human placenta as functions of maternal glucose concentration.

The impact of varying maternal glucose concentrations on glucose uptake, transfer, and metabolism was investigated in the human placenta perfused in vitro. The rates of placental glucose uptake from the maternal perfusate and transfer to the fetal perfusate were significantly correlated with maternal glucose concentration up to 20 mM. Placental glucose utilization was also dependent upon maternal glucose concentration up to 17 mM. Between 3 and 53 mM maternal glucose, lactate production increased 3-fold while no change in oxygen consumption could be demonstrated. Correlatively, glucose storage was shown to increase dramatically above 10 mM maternal glucose. These results suggest that glucose supply to the fetus may be limited in times of maternal hypoglycemia and that placental mechanism(s) may serve to buffer glucose transfer to the fetus in conditions of hyperglycemia.