Enzymatic measurement of tryptase-like protease release from isolated perfused guinea pig heart during ischemia-reperfusion.

To elucidate the details of tryptase release from the heart during ischemia-reperfusion (I/R), we attempted the enzymatic measurement of tryptase release from the isolated guinea pig heart perfused by the Langendorff mode I/R model. Tryptase-like activity in the effluent was monitored by the hydrolysis of L-Pyr-Gly-Arg-MCA. Tryptase-like protease and histamine were rapidly released from heart during ischemia within 10 min. After reperfusion, tryptase-like protease levels decreased, achieving stabilization. The tryptase-like protease activity in the effluent was inactivated by serine protease inhibitors. The pattern of inhibition was similar to those of guinea pig and human lung tryptase. In conclusion, tryptase was released into the coronary effluent during ischemia, but not during reperfusion in guinea pig heart.