Mechanism of the Potentiating Effect of Secretin-CCK in Rat Pancreas

Lee, Dong Ki; Kim, Jun Myeong; Kwon, Sang Ok; Park, Kyung Sun; Chung, Jae Bock; Kang, Jin Kyung; Kim, Kyung Hwan

Abstract

BACKGROUND/AIMS: The rnechanism of secretin and CCK potentiation effect was evaluated in the dispersed pancreatic acini of rat.
METHODS
To observe the presence of potentiating effect of secretin and insulin on CCK, the amount of amylase release according to secretagogues were measured. The mechanism of the potentiating effect of secretagogues were studied by measuring the change of the intracellular amount of cAMP and IP, and concentration of intracellular Ca"".
RESULTS
In the dispersed pancreatic acini, secretin potentiates the amylase release stimulated by JO and 10'""M CCK-8. Insulin slightly increased the secretory response to secretin plus CCK-8, but with no statistical significance. Secretin or forskolin did not increase the intracellular Ipy accumulation stimulated by CCK-8. Alo insulin had no influence on the intraeellular IP accumulation stimulated by CCK-8 plus secretin. CCK-8 and A23187 significantly decreased the intracellular cAMP accumulation stimulated by secretin. But the insulin did not influence the intracellular cAMP accumulation stimulated by secretin plus CCK-8. Secretin alone did not increase the intracellular concentration of Ca . Secretin and dibutyryl cAMP significantly increa- sed the intracellular concentration of Ca"" stimulated by CCK-8.
CONCLUSIONS
These results verify the presence of the potentiating effect of secretin but not insulin on CCK. Also the poten- tiating effect of amylase secretion by the simultaneous activation of the secretin and CCK was shown to be associated with increased intracellular Ca concentration, without a further elevation of intracellular IP or cAMP accumulation.