Proteolytic inactivation of lipase as a possible cause of the uneven results obtained with enzyme substitution in pancreatic insufficiency.

Inactivation of lipase in four commercially available pancreatin preparations in buffer solution, in duodenal juice stimulated by secretin-cholecystokinin or by Lundh test-meal, and in duodenal juice supplemented with a meat-meal homogenate, was examined during a four-hour incubation period. In the buffer solution and in the secretin-cholecystokinin-stimulated duodenal juice 64-89% of lipase activity was already lost within two hours. Trypsin activity was in inverse relation to that of lipase and soybean trypsin inhibitor. The Lundh test meal and the meat-meal homogenate significantly diminished inactivation of lipase. Substitution therapy of pancreatic insufficiency with crushed and soybean-trypsin-inhibitor supplemented preparations diminished steatorrhoea more effectively than the simple tablets. The demonstrated proteolytic inactivation of lipase indicates that pancreatic supplements have to be given in crushed or granulated form, well mixed with protein-containing meals, and that a physiological ratio of trypsin-lipase activity ought to be preserved in the preparations.