The fate of intravenously injected trypsinogens in dogs.

After intravenous injection of autologous purified and radiolabeled anionic and cationic trypsinogens in the dog, there is a multiexponential elimination from serum of the trypsinogens without activation to active trypsins. The results are in agreement with an elimination of the trypsinogens iva glomerular filtration, a variable tubular uptake of anionic trypsinogen, and a complete tubular uptake of cationic trypsinogen. Fractional catabolic rates for anionic trypsinogen were 0.35-0.92 h-1 and for cationic trypsinogen 0.38-1.05 h-1. The total amount of anionic trypsinogen turned over in the circulation is estimated at approximately 0.55 mg every 24 h, and the corresponding figure for cationic trypsinogen is 0.35 mg/24 h.