Relationships among canine fasting pancreatic and biliary secretions, pancreatic duct pressure, and duodenal phase III motor activity—Boldyreff revisited

Abstract

Despite the old observations of Boldyreff that pancreatic and biliary secretions occur during periods of intestinal contraction, quantification of these secretions and their relationships to duodenal motor activity and pancreatic ductal pressures have not been reported. By utilizing a recently developed canine model, we simultaneously measured these events. Each of nine dogs was provided with a permanent indwelling pancreatodochal cutaneous catheter (to monitor pancreatic pressure) and three duodenal cutaneous catheters. [¹⁴C]PEG was infused through the proximal catheter located in the first part of the duodenum and intraluminal duodenal pressures were monitored through the middle catheter, located at the level of the pancreatic duct orifice. From a third catheter located 15 cm distal to the middle catheter duodenal samples were siphoned, pooled over ice every 15 min, and analyzed for concentration of marker, lipase, and bilirubin. Duodenal volume flows and outputs of lipase and bilirubin were calculated relative to the recovery of the marker. All studies were done in fasting, conscious, upright dogs. Lipase and bilirubin outputs, duodenal volume flow, and mean pancreatic duct pressures increased (P<0.05) during phase III duodenal motor activity, compared with values 15 and 30 min before the onset and after the cessation of phase III motor activity. It is concluded that the inter-digestive housekeeper (phase III motor activity) is comprised of electric, motor, and digestive components. The amount of pancreatic enzymes secreted during phase III activity is 50% of that secreted during a similar time postprandially and is theoretically in sufficient quantity to hydrolyze food remnants and cellular debris. Thus it is likely that the association of increased pancreatic and biliary secretion with intense motor activity of the duodenum render the housekeeping action of the complex more effective.