Measurement of trypsin in duodenal juice by radioimmunoassay.

Trypsin in duodenal aspirate and pure pancreatic juice samples has been measured by both radioimmunoassay and enzymatic mathods. The radioimmunossay has been shown to be specific and to detect trypsin in the presence of aprotinin (Trasylol). In duodenal juice samples from control subjects and from patients with primary biliary cirrhosis a good correlation was obtained between both immunoreactive trypsin concentration and trypsin activity. The immunoreactive trypsinogen concentration in pure pancreatic juice also correlated well with activated trypsin activity. The mean immunoreactive trypsin concentration and the concentration of enzymatically inert immunoreactive trypsin in duodenal juice samples from patients with primary biliary cirrhosis were significantly lower than controls, suggesting pancreatic hyposecretion in this disease. After five duodenal juice samples had been stored for three months at -70 degrees C, immunoreactive trypsin concentration in samples stored without Trasylol were reduced by 12 . 0 +/- 4 . 2 (mean +/- SD) times the concentration of samples stored in Trasylol. Trypsin autodegradation continues even at -70 degrees C; Trasylol protects against this. Radioimmunoassay is a reliable method of trypsin estimation in duodenal juice and has advantages over conventional enzymatic analysis.