Important kinetic aspects of renin reaction were studied in order to evaluate the parameters that regulate the formation rate of angiotensin I. This rate decreased throughout the incubation period of normal rat plasma and it showed a linear increase  when plasma was incubated with renin-substrate. When renin was added to normal rat plasma a plateau in the angiotensin I formation rate occurred after 4-6 hours. When plasma samples containing increasing amounts of renin-substrate were incubated, the velocity of their reaction increased in proportion to the renin-substrate concentration. Under these incubation conditions, the reaction between endogenous renin and renin-substrate in normal rat plasma, proved to be a first kinetic order with respect to the substrate.
Angiotensin II Animals