Effect of changes in circulating amylase levels on amylase output in bile.

The relation between plasma and biliary amylase activity and their relationship to the functional state of the pancreas were studied in anesthetized rabbits. Repetitive intravenous injections of cholecystokinin resulted in a 25-fold rise in the secretion of amylase via the pancreatic duct, followed at first by a 50% increase in plasma amylase concentration and later by a 270% increase in biliary amylase concentration. There was then a gradual, roughly synchronous decline in both plasma and biliary values toward basal level despite a continued highly augmented rate of pancreatic ductal secretion. "Near-total" pancreatectomy completely abolished the effect. These observations are consistent with a cholecystokinin-induced basolateral secretion of amylase from pancreas into blood and its subsequent movement from blood into bile down a concentration gradient. The output of amylase in bile, however, was quite small and does not suggest that biliary transport of amylase has an important function either as a means of secreting and recycling digestive enzyme into the gut or as a major excretory pathway for circulating amylase in the rabbit.