EXPERIENCES WITH THE BIOLOGICAL ASSAY OF SEVERAL SYMPATHICOTONIC SUBSTANCES INCLUDING EPINEPHRINE

¹ From The Burroughs Wellcome & Co. U.S.A. Experimental Research Laboratories, Tuckahoe, N. Y.

Three pressor amines, namely, epinephrine, 3,4-dihydroxyphenethyl-methylamine and 3,4-dihydroxyphenethyldimethylamine were tested for relative potencies by an increasing dose method, and the data were studied to determine when linear relationships might be assumed. The following conclusions may be drawn:

1. The Weber-Fechner law may be said to hold for restricted ranges of our data but not for the data as a whole.

2. The application of a progressively increasing dose method to the biological assay of epinephrine may be an improvement upon the U.S.P.XI procedure.

3. Expressing relative pressor potencies on the basis of doses required to elicit a specific response may not convey a true picture when the characteristic slopes of the logarithmic dose-response curves of two compounds are not identical.

4. When the logarithmic curves of compounds being compared with epinephrine are dissimilar, it may indicate the presence of qualitative differences in action.