Levels and molecular forms of gastrin and somatostatin in plasma and in gastric contents of infants after section delivery.

We measured the pH of the gastric contents, as well as the gastrin- and somatostatin-like immunoreactivity in both plasma and gastric content samples, obtained from 23 infants delivered at term by elective cesarean section (ECS). In addition, we characterized the molecular forms of gastrin and somatostatin by high performance liquid chromatography. The median pH value of the gastric contents was found to be 6.78 (range 4.93-7.35). The median gastrin concentration in plasma was 54 pmol/L (range 29-190 pmol/L), which was significantly higher (p less than 0.0005) than the concentration recorded in the gastric contents, 6 pmol/L (range 0-680 pmol/L). The median somatostatin concentration in plasma was 12 pmol/L (range 4-40 pmol/L), which was significantly lower (p less than 0.0001) than the concentration found in the gastric contents, 128 pmol/L (range 15-488 pmol/L). Gastrin- and somatostatin-like immunoreactivity in both plasma and gastric contents were found to correspond to nonsulfated gastrin-34 and somatostatin-14, respectively. These data suggest that acid secretion is absent or low in infants immediately following ECS, although gastrin and somatostatin are being released into the circulation as well as into the gastric lumen. The different ratio between the concentration in plasma and gastric contents of gastrin (10:1) compared with that of somatostatin (1:10) might be related to the fact that gastrin exerts endocrine actions preferentially, whereas somatostatin is presumed to exert local paracrine effects on the gastric mucosa.