A novel serum assay for pancreatic cellular damage. II. High tissue specificity of a pancreatic protein.

A previously unknown major protein in human pancreatic cytosol has been purified and partly characterized. The protein, designated pancreas specific protein (PASP), has a molecular weight of 44,500 and a pI of 6.9. A two-dimensional gel separation technique revealed the protein to be specific for normal pancreatic tissue. Antibodies against PASP were raised in rabbits and a radioimmunoassay was developed for the quantitation of this protein. The following concentrations of PASP (mg/kg wet weight) were found in human tissues: normal pancreas 100-1,000; pancreatic carcinoma 0.1-20; prostate 0.5-5; and 13 other tissues less than 0.5. The levels of PASP in peripheral serum were less than 0.1 mg/L in normal subjects, 0.7-3 mg/L in cases of acute pancreatitis, and less than 0.1 mg/L in cases of pancreatic carcinoma, prostatic diseases, and other abdominal diseases investigated. The high tissue specificity and the specific elevation of serum PASP levels in acute pancreatitis may indicate a use of this protein as a marker of this pancreatic condition.