Phospholipase A Activity in Duodenal Aspirates of Man

Degradation of lecithin has been studied during incubation of a lecithin solution with duodenal aspirates from man after pancreatic stimulation by a standardized test meal. Phospholipids were quantitated after separation by means of thin layer chromatography on silica gel-coated glass plates. Calcium stimulated and EDTA inhibited the degradation of lecithin. No lecithin breakdown occurred after boiling the aspirate. pH optimum of the medium was 8.0. Lysolecithin was the major initial degradation product of lecithin. Lysolecithin degradation also took place. The degradation of lecithin by the juice collected from duodenum after a test meal is most probably enzymatic and due to pancreatic phospholipase A. Decreased amounts of this enzyme were found in patients with chronic pancreatitis. The method used in the present study has been found suitable for clinical studies of pancreatic phospholipase A of man.