Elimination of pancreatic secretory trypsin inhibitor from the circulation. A study in man

The elimination of human pancreatic secretory trypsin inhibitor (PSTI) from the circulation of man has been examined in two human volunteers. Serial samplings of blood and urine were made for 55 h, after a rapid intravenous infusion of 125I-labeled human PSTI. The findings demonstrated a rapid initial elimination from the circulation. Within 30 min only 30% of the infused label remained (T1/2, 6 min). This was accompanied by the rapid appearance in the urine of radiolabel. Our results indicate that PSTI would prove a poor diagnostic marker for acute pancreatitis late in the course of the disease. This is opposed to the findings of Ogawa et al., who reported prolonged elevated circulating levels of PSTI weeks into the disease. However, they also noted rises of PSTI during acute pancreatitis in excess of 10 times the levels we have noted. Further exploration of population differences and the behavior of PSTI during acute pancreatitis are necessary to help resolve these findings.