['Stimulation of low-affinity CCK-1 receptors on pancreatic acini leads to inhibition of enzyme secretion. We studied signal transduction mechanisms to identify potential causes for the reduced secretion.', 'Co-stimulation experiments with CCK, CCK-JMV-180, and bombesin revealed an inhibition of bombesin-stimulated enzyme secretion by low-affinity CCK-1 receptors. Binding of 125I-gastrin-releasing peptide (the mammalian analogue of bombesin) to acini after CCK preincubation was not altered. After a short preincubation of acini with high concentrations of CCK, intracellular calcium remained responsive to bombesin. In contrast to bombesin or CCK at concentrations of 10(-10) M or lower, high concentrations of CCK caused a strong activation of p125 focal adhesion kinase (p125(FAK)) and a marked reorganisation of the actin cytoskeleton.'] Do low-affinity CCK-1 receptors inhibit bombesin-stimulated secretion in rat pancreatic acini -- implication of the actin cytoskeleton?