Radioimmunoreactive serum elastase levels and histologic changes during experimental pancreatitis in rats

A radioimmunoassay system showed elastase levels of 128 to 232 ng/mL in normal rat serum. The average normal value was approximately 64-fold greater than the minimal detectable amount. No cross-immunoreactivity was found with human elastase 1, porcine elastase, and trypsin. The elastase and amylase levels in rat serum were measured during pancreatitis induced by trypsin (group 1) and normal saline solution (group 2). Within 15 minutes the serum elastase and amylase levels increased significantly and remained elevated. The serum elastase levels in group 1 were significantly higher than in group 2. Hemorrhagic pancreatitis was found in group 1 and edematous pancreatitis was found in group 2 five hours after induction of pancreatitis. Elastase levels in these tissues were significantly lower than those in normal tissue. The levels in ascitic fluid were higher than those found in serum.