Localization of somatostatin-, bombesin-, and serotonin-like immunoreactivity in the lung of the fetal rhesus monkey.

Immunoreactivity of regulatory peptides has been demonstrated in the fetal lung of Macaca mulatta by the peroxidase anti-peroxidase method. Serotonin-immunoreactive neuroepithelial bodies are distributed in the airways from the bronchi to the alveolar ducts. Many neuroepithelial bodies also show bombesin-like immunoreactivity; a very few are immunoreactive to somatostatin antiserum. Four populations of neuroepithelial bodies were identified which contain immunoreactivity for 1) serotonin alone, 2) serotonin and bombesin, 3) serotonin and somatostatin, and 4) serotonin, bombesin, and somatostatin. Since bombesin and somatostatin have been demonstrated to have opposite effects on the release of other peptide hormones, it seems likely that the presence of these same peptides in neuroepithelial bodies may have a similar regulatory role in the lung.