This study investigated the influence of extracellular matrix on growth and secretory function associated with cholecystokinin (CCK) receptors in pancreatic acinar AR42J cells, using reconstituted basement membrane derived from Engelbreth-Holm-Swarm (EHS) tumor. The cells were cultured with basement membranes of two different thickness, 1 mg/ml protein equivalent (thick RBM) and 50 micrograms/ml protein equivalent (thin RBM). In cells cultured with thin RBM, the secretory function and the number of CCK receptors increased, but cell growth did not increase significantly. Cells cultured with thick RBM showed remarkable cell growth, but secretory function and the number of CCK receptors were reduced. There was little change in CCK receptor affinity. It was concluded that the extracellular matrix plays a crucial role in the proliferation and differentiation of AR42J cells and further, the quantitative difference of matrix components strongly influenced the up- and down-regulation of CCK receptor in the cells via cell-matrix interaction.