Potentiation by crude kallikrein of the myotropic effect of angiotensin I in the isolated rabbit aortic strip.

Crude kallikrein (Padutin), but not pure kallikrein, when preincubated with angiotensin I caused a potentiation of the myotropic effect of decapeptide on the isolated continuously superfused rabbit aortic strip. Addition of converting enzyme inhibitor, SQ 20881, to the medium inhibited this potentiation. The potentiation by crude kallikrein of the myotropic effect of angiotensin I is probably due to the conversion of decapeptide to octapeptide angiotensin II. This study indicates that Padutin is not a pure kallikrein preparation and probably contains a kininase fraction which causes the conversion of angiotensin I.