Bombesin-like immunoreactivity in developing human lung.

Bombesin-like immunoreactivity (BLI) was detected by a specific radioimmunoassay in extracts of 15 human lungs from fetuses, neonates, infants and children. A higher concentration of lung BLI was found in the fetal/neonatal group (2053.2 +/- 316.3 ng bombesin/g protein, n = 6) compared to the infant/children group (416.3 +/- 64.3 ng/g, n = 9). The peaking of BLI in lungs during the fetal/neonatal period suggests an important function for this peptide in intrauterine life and neonatal adaptation.