FURTHER CONCERNS OVER CHENG-PRUSOFF ANALYSIS

In his article in last month's issue of TiPS (14, 89-91), Douglas Crai g discussed the application of the Cheng-Prusoff relationship to the a nalysis of antagonists in functional experiments. Craig described how the translation of this method from biochemistry to pharmacology can b e accompanied by errors due to theoretical misunderstanding. He also e mphasized the lower level of rigour associated with this means of esti mating antagonist affinity constants compared with Schild analysis. In this article, Paul Leff and Iain Dougall extend Craig's arguments by describing some additional ways in which the application of the Cheng- Prusoff method to pharmacological experiments are likely to result in misinterpretation and erroneous estimates of antagonist affinity.