The Biochemical Prerequisites for Preventing Pathogenic Lysolecithin Activity in the Human Gallbladder

Human gallbladder epithelium was disintegrated to complete loss of microscopic structure and incubated at 37 degree C together with unlabelled lysolecithin and 14C-lysolecithin. During each incubation lysolecithin was degraded and stoichiometrically equivalent amounts of free fatty acids formed. The maximum rate of degradation was obtained at pH 7.0 and at 200 muM lysolecithin. With increasing amounts of gallbladder epithelial cell constituents the reaction became faster. After heating the epithelial components at 70 degrees C for 10 min the reaction was inhibited. The results suggest the presence of a heat labile lysophospholipase (phospholipase B) activity in the human gallbladder epithelium. This activity may operate to protect the gallbladder epithelium against potentially pathogenic lysolecithin activity. Its presence in the gallbladder epithelium meets the prerequisites for a local anti-inflammatory mechanism and lends further support to the hypothesis of lysolecithin as a mediator of cholecystitis.