Plasma somatostatin concentration in the preterm neonate.

Plasma somatostatin concentration was measured by radioimmunoassay in 26 preterm neonates (mean gestational age 34 weeks). None were seriously ill and they were all fed with breast-milk 12 h after birth. In a longitudinal study the concentrations were (mean +/- SEM): 21 +/- 2 pmol/l (n = 8) at 2-8 h of age, 24 +/- 2 pmol/l (n = 11) at the age of 2 days and 25 +/- 2 pmol/l (n = 15) at the age of 8 days. These levels were significantly higher than in 30 healthy control adults: 11 +/- 1 pmol/l (P less than 0.01). Gavage with breast milk on the 2nd day induced a significant decrease from 21 +/- 4 to 15-2 pmol/l in 60 min (P less than 0.05). This data shows that the high plasma levels in neonates correspond to the high density of somatostatin in the neonatal pancreas and digestive tract. It also indicates that somatostatin is regulated by feeding in the neonate.