Metabolic responses to alanine in small-for-gestational age infants: developmental aspects.

14 small-for-gestational age (SGA) infants and 4 healthy adult volunteers were subjected to an intravenous alanine tolerance test. In normoglycemic SGA infants studied during the first 6 days of life, the apparent K value for the disappearance rate of alanine was 3%/min. In 6 hypoglycemic patients studied between day 1 and day 12 the corresponding K value was 2.2%/min. In adult volunteers a K value of 5.6%/min was obtained. Plasma pyruvate increased after alanine in both normoglycemic and hypoglycemic SGA infants. The blood glucose tended to decrease after the alanine load in the hypoglycemic infants, whereas an increase was observed in infants with normoglycemia. On reexamination of 4 hypoglycemic SGA infants after the blood glucose concentration had normalized, a blood glucose profile approaching that of normoglycemic infants was recorded.