High concentration of kynurenic acid in bile and pancreatic juice.

Kynurenic acid (KYNA) is an agonist of the G-protein-coupled receptor GPR35, which is predominantly expressed in gastrointestinal tissues. The aim of this study was to determine the content of KYNA in gastric juice, bile and pancreatic juice and intestinal content. KYNA was determined by means of high performance liquid chromatography. The mean concentrations of KYNA in human gastric juice is 9.91 +/- 0.71 nM in contrast to human bile (832.5 +/- 204.1 and 306.8 +/- 35.2 nM) obtained from patients with cholecystolithiasis and obstructive jaundice, respectively. In pigs, the KYNA levels in bile and pancreatic juice are 1,113.3 +/- 63.34 and 757.0 +/- 394.4 nM, respectively. The KYNA concentration increases along the digestive system, reaching 1,638 nM in the colon content. We suggest that the liver and pancreas affect the content of kynurenic acid in the lumen of the digestive tract.

Arterial gastroduodenal infusion of cholecystokinin-33 stimulates the exocrine pancreatic enzyme release via an enteropancreatic reflex, without affecting the endocrine insulin secretion in pigs.

OBJECTIVES: Cholecystokinin (CCK)-dependent exocrine pancreatic regulation seems to involve different pathways in different species. The aims were to explore the enteropancreatic reflex in the CCK-mediated regulation of the exocrine pancreas and to evaluate a possible involvement of this reflex in the endocrine insulin release. METHODS: In anesthetized pigs, CCK-33 in increasing doses (4-130 pmol kg 10 min) was infused locally to the gastroduodenal artery, or systemically via the jugular vein. Also, a low CCK-33 dose (13 pmol kg) was injected to the duodenum/antrum area before and after a bilateral truncal vagotomy. RESULTS: Cholecystokinin-33 in the physiological dose range 4 to 32 pmol kg 10 min increased protein and trypsin outputs after local infusion to the antral-duodenal area, whereas it had no effect after systemic infusion. Cholecystokinin-33 in the pharmacological dose range 64 to 130 pmol kg 10 min further increased the secretion after both local and systemic infusions. Only CCK-33 infusions in the pharmacological dose range were able to elevate the plasma insulin levels. Vagotomy had no effect on CCK-33-mediated stimulation of the enzyme release, whereas it had a significant effect on the plasma insulin level. CONCLUSIONS: Cholecystokinin-33 in the physiological dose range 4 to 32 pmol kg 10 min stimulates the enzyme secretion but had no effect on the insulin release via a short enteropancreatic pathway in pigs.

An elemental diet fed, enteral or parenteral, does not support growth in young pigs with exocrine pancreatic insufficiency.

BACKGROUND & AIMS: Young individuals with exocrine pancreatic insufficiency (EPI) show growth reduction that can be reversed by dietary pancreatic enzyme supplementation. Here we investigated whether feeding an elemental diet could replace the growth-promoting effect of enzyme supplementation in EPI pigs. METHODS: Weaned pigs with intact pancreas (control) or pancreatic duct-ligated (EPI pigs) were given a commercial pig feed, a fat-enriched diet, or an elemental diet, intragastrically and intravenously, with or without porcine pancreatin (Creon) supplementation for 1 week. RESULTS: Control pigs, irrespective of receiving pig feed or an elemental diet, increased their body weight by 13.4-20.1%, while EPI pigs showed negligible weight gain. Giving a fat-enriched diet did not improve growth of the EPI pigs. However, if the EPI pigs were supplemented with pancreatin in combination with fat-enriched feed or the elemental diet, i.v., their body weight increased by 16.6 %and 8.5%, respectively. CONCLUSION: Control pigs maintained normal growth, independently of the diet being given in polymeric or elemental form, while EPI pigs showed impaired growth when receiving the same diets without enzyme supplementation. Pancreatic juice and enzyme preparations, in addition to their digestive properties, also appear to affect nutrient assimilation and anabolism in young individuals.