ON THE IMPORTANCE OF CHOLECYSTOKININ IN NEONATAL PANCREATIC GROWTH AND SECRETORY DEVELOPMENT IN GUINEA-PIGS

The role of cholecystokinin (CCK) in pancreatic growth and secretory d evelopment in fetal and neonatal guinea pigs was investigated by CCK r eceptor blockade. For the last 20 days of gestation, sows received the CCKA receptor antagonist, MK329 (25 nmol/kg/h) by continuous subcutan eous infusion. Alternatively, neonates from untreated females received an MK329 infusion for the first 4 or 15 days following birth. Pancrea tic weight, DNA, RNA, protein, and amylase content per 100 g body weig ht and secretory responses to CCK, carbamylcholine, and phorbol eater were determined at birth and 4 days in animals receiving MK329 in uter o and were measured at 4 and 15 days in neonatally infused animals. No significant changes in pancreatic growth parameters were seen in MK32 9-treated animals compared to controls, except for a small (14%; p < 0 .02) decrease in weight after 15 days of neonatal exposure. Enhanced a mylase secretion in response to CCK and carbamylcholine was seen in al l groups receiving MK329 (all p values < 0.00001). Pancreatic growth a nd secretion were not inhibited by CCKA receptor blockade, which sugge sts that the effects of CCK mediated by the CCKA receptor are not esse ntial for growth or development of the pancreatic amylase secretory re sponse in the neonatal guinea pig.