KININOGEN IN PLASMA FROM CAT, HAMSTER AND GUINEA-PIG

The kininase activity and the level of the two kininogens, substrate 1 and 2, have been determined in plasmas from cats, hamsters and guinea‐pigs. Kininase activity was found to be far more pronounced in the latter type of plasma than in the former ones. The efficiency of di‐sodium edetate and phenanthroline as kininase inhibitor was also evaluated in the three plasma types. In plasma from cat and hamster, human plasma kallikrein was found to release kinins from the socalled substrate 1 only, whereas in guinea‐pig plasma the same agent released kinin from both types of kininogens. The animal's own saliva acted only upon substrate 2 in plasma from cat and guinea‐pig, whereas it induced kinin formation from both substrates in plasma from hamster. Ellagic acid and glass contact released kinins from substrate 1 only in all three plasma types. Intravenous injection in hamsters and guinea‐pigs of a buffered solution of ellagic acid, caused pronounced effects on blood pressure and respiration. On repeated injections these effects subsided. After four such injections the concentration of substrate 1 in arterial blood samples from hamsters was found to be very low (varying from 0 to 20 %). The level of substrate 2 was, however, unchanged. The level of substrate 1 reached 83 % of the initial value after 24 hrs. © 1969 Scandinavian Physiological Society