[Presence of a renin inhibitor in the plasma of intact dogs].

The authors elaborated a method of determination of the plasma renin inhibitor based on the statement that with successive dilution of the plasma the velocity of the renin + substrate reaction in the presence of an inhibitor fell more slowly than the extent of dilution, and, on the contrary, in the plasma without any inhibitor the rate of the reaction decreased more than the value of the plasma dilution. This statement follows from the equations of the reaction suggested by Dixon and Webb (1966). With the aid of this method the presence of the renin inhibitor in the plasma was found in 8 of 19 intact dogs examined.