Intravenous amino acids and stimulation of gastric acid secretion in infants.

To determine the immediate, short-term effect of intravenous amino acids on gastric acid secretion in infants, we measured acid secretion by continuous aspiration of gastric contents in nine enterally fed, chronically ill infants who required intravenous supplements. On day 1, basal acid output was 25 +/- 15 mumol/kg/h (mean +/- SD), and postpentagastrin maximal acid output was 91 +/- 59 mumol/kg/h. On day 2 basal acid output was 24 +/- 16 mumol/kg/h. Acid output was measured for 4 h following addition of amino acids to the intravenous solution. The rate of amino acid infusion was 0.15 g/kg/h. The infusion of intravenous amino acids resulted in an immediate and sustained twofold increase in acid secretion. Hourly totals of amino acid-stimulated acid output were 51 +/- 38, 44 +/- 37, 46 +/- 30, and 47 +/- 31 mumol/kg/h in hours 1-4, respectively. These results were significantly different from basal acid output (p less than 0.01) during the last 2 h of amino acid infusion. Serum gastrin concentration was not significantly different before and after the amino acid infusion (87 +/- 63 pg/ml vs. 105 +/- 56 pg/ml). We conclude that amino acids infused at a rate typical for parenteral nutrition stimulate gastric acid secretion in infants.