Relationship between lower esophageal sphincter pressure and serum gastrin concentration in the newborn infant.

We measured lower esophageal sphincter pressure in 22 healthy unsedated term neonates (mean age 8.25 hours) with a double-lumen tube, continuously perfused manometric system. Studies were repeated in 18 infants on day 4. Serum gastrin concentration was measured with 34 studies and in 22 adult controls. Mean (+/- SD) LESP and serum gastrin concentration, respectively, were 41.9 mm Hg (+/- 10.9) and 142.6 pg/ml (+/- 56.0) on day 1 and 39.1 mm Hg (+/- 11.5) and 144.9 pg/ml (+/- 54.5) on day 4. LESP did not correlate with age on day 1 or with serum gastrin concentration on either day 1 or 4. Serum gastrin concentration in the adult controls (98.9 pg/ml +/- 35.4) was significantly higher than that of the neonates. We conclude that LESP is well developed in the healthy term neonate. Although neonatal serum gastrin concentrations are higher than in the adult, they do not correlate with LESP, and endogenous gastrin probably plays no role in the maintenance of basal LESP in the newborn infant.