Abstract
Two general types of precipitation phenomena were seen in postoperative collections of human ductal pancreatic juice. Concentration-dependent precipitation took place when specimens of inactive pancreatic juice secreted at concentrations above 3 mg/ml were chilled on ice or stored at 4°C. These fine precipitates, when freshly formed, were redissolved by warming at 37 °C. A different type of precipitation occurred with specimens of active pancreatic juice. Insoluble flocculent precipitates were formed even from dilute solutions and did not redissolve by warming at 37 °C. Based on these observations, an alternate mechanism of protein plug formation is proposed which invokes a series of partial activations resulting in precipitate formation in the ductules, as an initial step, followed by the development of protein plugs from these precipitates through the slow adsorption of salts and proteins, such as lactoferrin, from newly-secreted pancreatic juice.