Control of glucose metabolism in the perinatal period.

The central importance of glucose as a fuel for energy metabolism and growth of the fetus is clear as is the role of insulin in coordinating its utilisation by many fetal tissues. What is less clear is the qunatitative nature of the interaction between the fetus and placenta in organising glucose metabolism. Increasingly there is evidence that the fetus coordinates some of the supply of glucose to the placenta and that this is particularly important when uterine blood flow is reduced. It is unclear how this is regulated, but substrate cycles of glucose and lactate appear to make a significant contribution to carbohydrate metabolism in fetus and placenta. Another area as yet unresolved in the control of fetal glucose metabolism is the coordination of the changes that occur around the time of birth. Notable of these is the activation of glycogen mobilisation and of glucose synthesis and changes in the setting of glucose regulatory mechanism. These are briefly reviewed.