Duodenal secretion of lysosomal enzymes in rats stimulated with gut hormones

To determine the pattern of lysosomal enzyme secretion into gastrointestinal fluids, we measured cathepsin B activity in the duodenal juice of rats stimulated with vasoactive intestinal polypeptide (VIP) (0.1 μg/kg.hr). In duodenal juice, VIP caused a significant increase in bicarbonate, protein and cathepsin B output which were positively correlated. These results indicate that the secretion of lysosomal enzymes into gastrointestinal fluids is stimulated by gut hormones and that lysosomal enzymes play a physiological role in gastroduodenal fluids, such as in digestion or modification of digestive enzymes