MEPACRINE INHIBITS AMYLASE SECRETION MEDIATED BY A GUANYLNUCLEOTIDE BINDING-PROTEIN

1. In intact rat pancreatic acini, 10 nM bombesin, 100 nM phorbol este r TPA and 10 mM fluoroaluminate increased amylase secretion 5-, 3- and 4-fold respectively. 2. Mepacrine dose-dependently inhibited the resp onse to bombesin and fluoroaluminate but did not affect the response t o TPA. 3. In permeabilized acini, mepacrine inhibited the secretory re sponse to GTP gamma S without modifying the response to TPA.