Human placental transfer of glucagon.

Recent studies measuring fetal cerebral oxygen and glucose uptake in sheep indicate that the requirements of the fetal brain are comparable to those of the adult (Makowski, Schneider, Tsoulos, Colwill, Battaglia & Meschia, 1972). Since oxygen and glucose contents of arterial blood perfusing the fetal head are considerably less than in the adult animal, there would appear to be a low margin of safety with respect to oxygen and glucose supply to the fetal brain. During periods of stress in utero the requirements of the fetal brain for glucose might be met by the role of glucagon as the regulator of nutrient mobilization. The role of maternal glucagon, if any, would depend upon its ability to cross the placenta. The permeability of human chorion to 1251-labelled glucagon is described below.