Tachyphylaxis to Renin

Abstract

Conclusions

1. A method is described which will give a reliable, relatively stable, active “renin” preparation. 2. The method of preparing the “renin”, the use of acetone in its preparation, the type of anesthesia used for the assay animal, species difference between source and assay animal, do not appear to affect significantly the appearance of the phenomenon of “tachyphylaxis” or tolerance. 3. The time interval between successive injections does significantly affect the appearance of tachyphylaxis, and the effect is more pronounced the shorter the interval. 2 The effect is least noticeable when the interval is 120-180 minutes. 4. Assay procedures carried out in dogs where the interval between successive injections is less than 2 hours are misleading unless the phenomenon of tolerance is taken into consideration.