[Simultaneous determination of gastric emptying and bile and pancreatic enzyme secretion]

Intestinal perfusion methods with a nonabsorbable marker allow an exact quantitative determination of intestinal absorption and secretion provided that methodological pitfalls are avoided. A modified technique is applied to the simultaneous measurement of biliary and pancreatic secretion during and depending on emptying of a mixed test meal. A duodenal segment was perfused with an isotonic polyethyleneglycol solution (PEG). Reinjection of duodenal aspirates maintained a normal enterohepatic circulation of bile acids (interruption less than 10%). The perfusion was performed in healthy volonteers over a period of 12 to 24 hours, with three mixed formula meals containing 51CrCl3 as a marker ingested at conventional feeding hours. Influence of meal size was studied by means of a high caloric (40 Kcal/b. wt. per day) test meal. Patients with cholesterol gallstones and cirrhosis of the liver only received one formula test meal of 300 Kcal. Instead of concentrations output of trypsin, lipase, bile acids and cholesterol (the latter corrected for duodenal absorption) was calculated from the dilution of PEG in the duodenal juice and gastric emptying was determined by following quantitatively the flow of 51CrCl3. Gastric emptying can be expressed by a single exponential function over most of the time. Only the last 60-100 Kcals were expelled by the stomach at a faster rate. The daily biliary and pancreatic secretion depend indirectly on the amount of food ingested. But during the day light hours (with continuous meal flow), secretion was similar in high and low caloric subjects, while a significant difference became obvious during night hours corresponding to differences in gastric emptying time. Mean hourly output of bile acid, biliary cholesterol, trypsin and lipase is independent from meal size and secretion of pancreatic enzymes reaches the values close to those after maximal stimulation by i.v. CCK-PZ. Output of pancreatic enzymes does not differ in health and gallstone disease or cirrhosis of the liver respectively. Since during digestion in normals approximately one forth of the bile acid pool is secreted hourly into the gut, the number of daily enterohepatic cycles of bile acids can be calculated by 4-6. Patients with cholesterol gallstones maintain normal bile acid output by enhanced cycling of the small pool: An average of 50% of the pool passed the duodenum per hour. A decreased bile acid pool is also present in cases of advanced cirrhosis of the liver. However, hourly output of bile acids in these patients is significantly less than in mild cirrhosis (with normal bile acid pool) or normal controls. Therefore the hourly fraction of the pool secreted is similar to healthy subjects. These findings provide an important information to explain abnormalities in bile acid metabolism in cirrhosis.