Human maternal and fetal serum insulin and growth hormone (HGH) response to glucose and leucine.

Maternal and fetal serum insulin and HGH responses to glucose, leucine, and glucose plus leucine were examined by infusions to pregnant women at term immediately before cesarean section. Leucine (15 gm.) with glucose (50 gm.) administered for 30 minutes to the mothers stimulates markedly maternal and fetal insulin secretion while infusion of glucose (50 gm.) causes a lower insulin response. When infusing glucose alone we noted that the duration rather than the degree of hyperglycemia determined the fetal insulin response. In fact, when glucose is given to the mother for 60 minutes the fetal insulin response is higher than when the same dose is infused for 30 minutes. Maternal infusion of leucine (15 gm.) for 30 minutes elicits only a very slight increase of insulin secretion in the mother and no change in the fetus. None of the infusions causes any alteration whatsoever in either maternal or fetal HGH secretion.