Vasoactive intestinal peptide (VIP) in preterm and term neonates.

There is a little information on vasoactive intestinal peptide (VIP) in the neonatal period. We have measured plasma concentrations of this biologically important peptide in 159 preterm infants and 98 term neonates. Preterm neonates during the first four days of life had plasma VIP concentrations which were five times greater than the levels in 12 healthy adult controls (9.6+/-0.7 pmol/l, mean +/-S.E.M., compared with 1.9+/-0.5 pmol/l, p less than 0.001), and these elevated concentrations persisted throughout the neonatal period. In contrast term infants on the sixth day of life, had plasma VIP concentrations only half those seen in preterm infants on the same post natal age (p less than 0.001). Bottle-fed term infants had higher VIP levels than those who were breast fed (5.6+/-0.4 vs. 4.3+/-0,4, p less than 0.05). Plasma VIP concentrations did not change following a feed in any of the groups of neonates studied. The high plasma levels of VIP described may indicate a reduced neuropeptide clearance mechanism in neonates or alternatively, suggest a hitherto unrecognised role for this peptide hormone in the neonatal period.