Plasma concentrations of aminoterminal pro atrial natriuretic peptide and aminoterminal pro brain natriuretic peptide in healthy neonates: marked and rapid increase after birth.

Objective: The purpose of the study was to examine the possible age dependency of plasma N-terminal pro atrial natriuretic peptide (N-ANP) and N-terminal pro brain natriuretic peptide (N-BNP) levels in healthy term neonates to establish normal ranges for the neonatal period.

Methods: N-ANP and N-BNP plasma concentrations were measured in peripheral venous (n = 116) and umbilical cord blood (n = 37) in 153 healthy term neonates (mean: 5.1; range: 0-30 days) using an enzyme immunoassay.

Neonatal blood plasma is less susceptible to oxidation than adult plasma owing to its higher content of bilirubin and lower content of oxidizable Fatty acids.

Newborn infants are susceptible to a range of problems attributed to excessive production of free radicals. Because of a higher content of antioxidants, above all bilirubin, and a lower content of oxidizable lipids, newborn plasma should be better protected against oxidation than adult plasma. To test this hypothesis, we measured the susceptibility of plasma to in vitro oxidation in microsamples (7 microL) from 57 healthy newborns and 18 adults.