Biochemical reactions involved in pancreatic enzyme secretion. 4. Effects of cytochalasin B on functions of the exocrine pancreas.

These experiments were performed to evaluate the effects of cytochalasin B on pancreatic enzyme secretion and thus perhaps establish a role for microfilaments in the exocytosis process. The alkaloid at a concentration of 1 microgram/ml (2micron) inhibits amylase secretion induced by urecholine or cholecystokinin-pancreozymin (CCK-PZ) but does not modify that induced by dibutyryl cyclic AMP. The inhibitory effect of the drug is reversible after a 30-min washing out period. It does not affect O2 consumption, basal calcium efflux, or efflux caused by CCK-PZ. Amino acid accumulation in the tissue and their incorporation into proteins are not modified. It is suggested that cytochalasin B inhibits pancreatic enzyme secretion, probably through an effect on the microfilament system.