Effects of gastrin-releasing peptide and analogues on guinea pig nasal mucosal secretion.

The effects of gastrin-releasing peptide (GRP), bombesin, GRP-(1-16) and GRP-(21-27) on guinea pig nasal mucosal secretion were studied in vivo. GRP, bombesin, and GRP-(21-27) induced significant secretion of total protein, albumin, and alkaline phosphatase. GRP induced significant secretion at lower concentrations (10(-11) and 10(-10) M) than were required for bombesin and GRP-(21-27) (10(-7) M). GRP-(1-16) did not stimulate secretion, indicating that the COOH-terminal region of GRP contained the secretagogic principle. Capsaicin, a stimulant of nociceptive sensory nerves, stimulated GRP release into nasal secretions. These data suggest that GRP is present in guinea pig nasal mucosa and that the COOH-terminal region of GRP may regulate mucosal macromolecule secretion.