EFFECT OF CHRONIC AMYLASE INHIBITION ON PANCREATIC GROWTH AND ACINAR CELL SECRETORY FUNCTION IN RATS

Wheat amylase inhibitor (WAI) was given to growing rats to determine w hether chronic inhibition of intraluminal amylase activity alters panc reatic growth, pancreatic enzyme composition, and secretory responsive ness to cholecystokinin octapeptide (CCK-OP) and carbachol. For 21 day s 13 rats were fed amylase inhibitor (AI) as 2.72% of the weight of th eir food; 13 were pair-fed controls (PFC), and 12 were controls with f ree access to food (FAC). Amylase and lipase secretion was measured fr om isolated pancreatic acini in response to CCK-OP (10(-12)-10(-18) M) and carbachol (10(-8)-10(-3) M). AI and PFC rats had similar food int akes and weight gains, pancreatic weights, and contents of enzymes (am ylase, lipase, trypsin, chymotrypsin), protein, and RNA, but these mea surements were significantly reduced compared to those of FAC rats. DN A contents per milligram of pancreas and per gram of body weight and a mylase/DNA and trypsin/DNA were similar among all groups. Lipase/DNA a nd chymotrypsin/DNA in AI rats were the same as in PFC rats but signif icantly lower than in FAC rats. In response to CCK-OP, amylase secreti on was similar in all three groups, but in response to carbachol amyla se secretion was significantly less in Al compared to PFC and FAC rats . Lipase secretion increased in response to CCK-OP in AI compared to P FC and FAC rats but was similar in all three groups in response to car bachol. Long-term inhibition of intraluminal amylase activity suppress es pancreatic growth and content of enzymes and RNA by reducing food i ntake and weight gain and also decreases acinar cell secretion of amyl ase in response to carbachol and increases lipase secretion in respons e to CCK-OP.