Inhibition of glucagon secretion in the human newborn by glucose infusion.

Plasma glucagon, serum insulin, and blood glucose responses during a 30-min glucose (1 g/kg body wt) or saline infusion were reported in 37 full-term and 35 preterm infants. They were studied either on the first day of life before feeding was initiated or during the first week of life. Glucose infusion promptly suppressed glucagon secretion in all infants even from the initial hours of extrauterine life. The mean maximal decrement in percentage in the full-term infants on the day of birth and older was 54 +/- 4% and 61 +/- 6%, respectively, while the maximal decrement in the preterm infants on day of birth and older was significantly lower (44 +/- 3% and 38 +/- 4%, respectively). The insulin response to glucose was variable in all infants and most of them showed a delayed rise of serum insulin. No change in plasma glucagon, blood glucose, and serum insulin was observed during and after saline infusion.