Human pancreatic exocrine response to nutrients in health and disease.

Accepted 29 March 2005 . . . . . . . . . . . . . . . . . . . . . . . 1.0 INTRODUCTION Optimal digestion and absorption of nutrients requires a complex interaction among motor and secretory functions of the gastrointestinal tract. Digestion of macronutrients is a prerequisite for absorption and occurs mostly via enzymatic hydrolysis. In this context, pancreatic enzymes, in particular lipase, amylase, trypsin, and chymotrypsin, play the most important role but several brush border enzymes as well as other pancreatic and extrapancreatic enzymes also participate in macronutrient digestion. The crucial importance of pancreatic exocrine function is reflected by the detrimental malabsorption in patients with untreated pancreatic exocrine insufficiency, which is a typical complication of, for example, chronic pancreatitis. Comprehensive knowledge about the physiological pancreatic exocrine response to normal diets and to individual food components and about alterations in pancreatic exocrine insufficiency is necessary to administer a pancreatic enzyme preparation which imitates physiological conditions closely. Although many efforts have been made to substitute for pancreatic exocrine insufficiency by specially designed pancreatic enzyme preparations, these still have several disadvantages compared with physiological enzyme secretion. In particular lipid absorption is not completely normalised in most patients. As a basis for a better understanding of pancreatic exocrine function in health and disease this review will first summarise literature data on pancreatic exocrine response to a normal diet and to administration of individual food components in healthy humans. The next chapter will focus on pancreatic responses to a normal diet and to administration of individual food components in patients with pancreatic diseases, in particular chronic pancreatitits, but also in patients with other pancreatic and non-pancreatic diseases which are associated with intraluminal lack of pancreatic enzymes, for instance coeliac disease and diabetes mellitus. Other evidence of pancreatic involvement and dysfunction in these diseases will also be discussed, particularly if sufficient data on endogenously stimulated pancreatic secretion are lacking.