Plasma, glucose, glucagon, and insulin responses to oral feedings of l-alanine were assessed in 44 healthy term infants during the first three days of life. Alanine administration produced significant increases in glucagon and glucose concentrations on day 1, but not on days 2 and 3. These increases occurred within 30 minutes (mean and SEM for glucagon, 127 ± 7 to 219 ± 16 pg/ml, P < 0.001; glucose, 45 ± 3 to 60 ± 7 mg/100 ml, P < 0.01) and persisted at the P < 0.05 level at four hours. Responsiveness to alanine seemed to be related to the baseline blood glucose levels since constant infusions of glucose inhibited the response. These results indicate that the pancreatic islet alpha cell secretion mechanism(s) is functioning in the newborn.
Abnormal plasma glucose and insulin responses in heterozygous lean (ob/+) mice