Structural requirement for galanin action in the pancreatic beta cell line Rin m 5F.

Galanin fragments were tested for their ability to alter forskolin-stimulated cyclic AMP production and insulin release from Rin m 5F cells. Galanin and its fragments inhibited both events with the following potencies: Gal-(1-29) greater than N-AcGal-(2-29) greater than Gal-(2-29) greater than Gal-(1-15). In contrast, Gal-(3-29), Gal-(10-29) and [Ile2]Gal were inactive. [Phe2]- and [Tyr2]Gal were moderately effective. We conclude that the N-terminal portion of galanin (in particular the aromatic amino acid in position 2) is crucial for activity.