We evaluated pancreatic enzyme secretory response to secretagogues (cAMP- and Ca2+-mediating) involved in exocytosis and in chloride channel activation in an exon 10 knockout cystic fibrosis (CF) mouse model. Experiments were performed in isolated pancreatic acini from liquid-fedCftr-/-mice (5∼6 wk of age) and age-matchedCftr+/+controls fed a solid or liquid diet. BrcAMP and forskolin alone induced higher amylase secretion (% initial amylase content) in theCftr+/+acini than carbachol (p< 0.05). Carbachol and BrcAMP or BrcAMP and forskolin, given in combination, produced additive effects on enzyme secretion in theCftr+/+acini. Ca2+- and cAMP-mediated amylase secretion in isolated pancreatic acini from theCftr-/-mice was no different to that observed in the age- and diet-matchedCftr+/+animals. However,Cftr-/-pancreatic acini showed a significantly greater amylase response to the combination of BrcAMP and carbachol than the sum of the individual responses in separate experiments (p< 0.05). The amylase response was not different in acini from solid-fed or liquid-fedCftr+/+controls. In summary, this study suggests that cystic fibrosis transmembrane conductance regulator is not essential for enzyme secretion as evidenced by no reduction in cAMP-mediated amylase secretion inCftr-/-mice. The results inCftr+/+acini suggest pancreatic enzyme secretion is mediated via multiple intracellular pathways acting in parallel and probably converge at a distal step in the secretory process. However,Cftr-/-pancreatic acini exhibited a synergistic secretory response following stimulation by BrcAMP plus carbachol. The enhanced secretory response may partially contribute to the development of pancreatic dysfunction in CF patients by facilitating occlusion of digestive enzymes in the secretory canaliculus of the pancreatic acini.