TRYPSINOGEN SECRETION FROM THE ISOLATED GUINEA-PIG PANCREAS IN RESPONSE TO SECRETAGOGUES

A study has been made of secretagogues inducing release of trypsinogen from superfused guinea pig pancreatic segments by using an on-line sp ectrophotometric system. Cholecystokinin octapeptide (CCK-8; 3.16x10(- 11)-10(-7) M), acetylcholine (ACh; 10(-7)-3.16x10(-5) M), vasoactive i ntestinal polypeptide (VIP; 10(-9)-10(-6)h M), secretin (10(-9)-10(-6) M) and histamine (10(-7)-10(-3) M) individually evoked significant in creases in trypsinogen release. A potentiating effect occurs when CCK- 8 is employed in combination with secretin but not with histamine. The activation of protein kinase C (PKC) by the phorbol ester 1 2-O-tetra decanoylphorbol-13-acetate (TPA) also increased trypsinogen secretion. In conclusion this study describes the usefulness of an on-line autom ated method to measure trypsin release in response to several pancreat ic secretagogues which are acting through different stimulus-secretion coupling pathways.