Plasma gastrin-34 increases during and immediately after breast-feeding in 3-day-old infants.

We examined whether plasma gastrin concentration increases during breast-feeding in infants. The peptide concentration was measured cross-sectionally before, during, and after breast-feeding in healthy, 3-day-old infants (n = 72). Somatostatin, a modulator of gastrin release, was also analyzed. Both peptides were measured by radioimmunoassay and were further characterized by high-performance liquid chromatography (HPLC). The (mean +/- SD) concentration of gastrin rose significantly from 63 +/- 24 pmol/L before feeding to 92 +/- 32 pmol/L (p less than 0.01) and 95 +/- 21 pmol/L (p less than 0.01), 5 and 10 min after the initiation of sucking, respectively. The gastrin concentration was 102 +/- 35 pmol/L (p less than 0.01) immediately after feeding. Plasma somatostatin concentration was unaffected by feeding. As assessed by HPLC, circulating gastrin before, during, and after feeding was found to correspond to gastrin-34, whereas circulating somatostatin was found to correspond to somatostatin-14. We conclude that in contrast to earlier studies, plasma gastrin concentration increases during and immediately after breast-feeding in infants.