Pancreatic endocrine response to the first feed in term newborn infants.

Blood glucose, insulin, C-peptide and glucagon were evaluated in 36 newborn term infants at birth, and before and 60 min after the first feed during the first day of life. Under basal conditions glycaemia diminished during the first day of life and glucagon increased, while insulin and C-peptide did not show any variation. The C-peptide: insulin molar ratio was higher in the newborn than in adults because of the longer half-life of C-peptide, probably due to reduced renal function in the neonatal period. The subjects were divided into two groups: 18 newborn infants were given a feed of commercially available milk powder reconstituted in water at 10% (5 ml/kg); the other 18 were given a feed of 5 ml/kg 10% glucose solution. In each group 6 were given the first feed after a fast of 6 h, 6 after a fast of 12 h and 6 after a fast of 24 h from birth. After the first feed with milk, the average increase of glycaemia was 19.83 mg%, of insulin 6.06 muU/ml, and of C-peptide 1.88 ng/ml. After the first feed with glucose the average increase of glycaemia was 13.59 mg%, of insulin 2.46 muU/ml, and of C-peptide 0.59 ng/ml. Glucagon did not show significant changes after the first feed.