Molecular size distribution of serum
elastase 1 was investigated, by means of
Sephadex G-200 gel filtration, in 10 patients with
acute pancreatitis and in 19 patients with
pancreatic cancer associated with high values of serum
elastase 1. The elution profile of immunoreactive
elastase 1 (IRE1) showed a single peak in the molecular position of the alpha 1-antitrypsin-elastase 1 (alpha 1-AT-E1) complex in all 10 patients with
acute pancreatitis, six of seven patients with
cancer of the pancreatic body-tail, and in the two patients with
cancer of the pancreatic uncinate without poststenotic dilatation of the main pancreatic duct. The elution profile of all patients with pancreatic
head cancer and one of seven patients with pancreatic body-tail
cancer with a poststenotic dilatation of the main pancreatic duct showed two peaks: the first was eluted in the position of the alpha 1-AT-E1 complex, and the second was eluted between alpha 1-AT-E1 and
elastase 1. The molecular weight of the IRE1 appearing specifically in patients with
cancer of the pancreatic head was about 46,000 to 48,000, which was different from the 30,500 molecular weight of (pro)
elastase 1. It is possible that
proelastase 1 binding with an unknown substance exists in patients with
pancreatic cancer. These data suggest that the
stenosis or obstruction of the pancreatic duct by
cancer probably liberates
proelastase 1 from the normal pancreatic acinal cells into the blood. Therefore, the determination of the molecular size distribution of
elastase 1 in the serum appears useful in the differential diagnosis of
acute pancreatitis and pancreatic
head cancer accompanied by
pancreatitis.