Abstract
Cholecystokinin (CCK) is secreted from CCK secretory cells in mucosa of the upper small intestine. The secretory mechanism was studied using intestinal epithelial cells isolated from the mucosa of rat upper small intestine and CCK stimulating substances. The secretion of CCK from the isolated cells was confirmed by immunohistochemical and immunofluorescence staining and by measurement of CCK in the cells and culture medium using specific antibodies against CCK. Release of CCK was stimulated by the CCK stimulating substances, L-phenylalanine, phorbol ester, dibutyryl cyclic AMP, bombesin (BBS) and CCK releasing peptide. The stimulation by L-phenylalanine and BBS was dependent upon extracellular calcium ion. Staurosporine and N- (6-aminohexyl) -5-chloro-1-naphthalenesulfonamide (W-7) reduced the release of CCK from the BBS-stimulated cells. Isolated rat intestinal epithelial cells are thus useful in the study of the mechanism of CCK secretion.
