title: Does the pancreas really produce much more lipase than required for fat digestion?
abstract: Thirty years ago, it was reported that a linear relationship does not exist between the amounts of human pancreatic lipase secreted in chronic pancreatitis and the degree of steatorrhea, which was considered to appear only after more than 90% of the pancreatic secretory capacity had been lost. From these observations, it was generally thought that the lipolytic potential of the pancreas is much higher than required. In recent years, however, it has been noted that: 1) the level of inhibition of digestive lipases and gastrointestinal lipolysis by the lipase inhibitor orlistat were almost linearly correlated with the amount of excreted fat; 2) in minipigs with experimentally-induced pancreatic exocrine insufficiency, the amounts of enteric-coated pancreatic extracts needed for restoring fat digestion to normal levels were estimated to be much higher than those usually administered; 3) human pancreatic lipase specific activity on meal triglycerides is 3 orders of magnitude lower than the very high specific activity usually measured under experimental in vitro conditions which are far from physiological conditions; 4) in patients with reduced human pancreatic lipase secretion, gastric lipase plays a significant role in fat digestion. This last observation might explain the absence of a linear relationship between human pancreatic lipase secretion in chronic pancreatitis and steatorrhea. From the low specific activity displayed by human pancreatic lipase on meal triglycerides, one can better understand why more lipase than expected is needed, why fat digestion lasts for more than a few minutes and, finally, why there is not such an excess secretory capacity for lipase as had been previously thought.
authors.affiliation: Laboratory of Enzymology at Interfaces and Physiology of Lipolysis, CNRS UPR 9025-IBSM, Marseille, France. carriere@ibsm.cnrs-mrs.fr
authors.forename: Frédéric
authors.initials: F
authors.lastname: Carrière
authors.forename: Philippe
authors.initials: P
authors.lastname: Grandval
authors.forename: Peter C
authors.initials: PC
authors.lastname: Gregory
authors.forename: Christophe
authors.initials: C
authors.lastname: Renou
authors.forename: Friederike
authors.initials: F
authors.lastname: Henniges
authors.forename: Suntje
authors.initials: S
authors.lastname: Sander-Struckmeier
authors.forename: René
authors.initials: R
authors.lastname: Laugier
mesh_terms: D000818:Animals; D004041:Dietary Fats / Q000378:metabolism*; D004063:Digestion; D010188:Exocrine Pancreatic Insufficiency / Q000188:drug therapy / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000378:metabolism; D006801:Humans; D007408:Intestinal Absorption; D008049:Lipase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D050356:Lipid Metabolism; D008066:Lipolysis; D010179:Pancreas / Q000201:enzymology*; D010195:Pancreatitis / Q000201:enzymology / Q000503:physiopathology; D045602:Steatorrhea / Q000201:enzymology / Q000503:physiopathology; D014280:Triglycerides / Q000378:metabolism
chemical_list: D004041:Dietary Fats; D014280:Triglycerides; D008049:Lipase