ACTION ON CELLULAR AND TISSUE METABOLISM 



505 



Finally, one must consider relationships of a more physiological nature. 

 The level of metabolic activity, and perhaps even the pattern of metabolism, 

 is related to the functional state of the cells (page 462). An inhibitor de- 

 pressing by any means the cell functions will secondarily modify metabolism 

 and is thus able to ])roduce an abnormal state that will not be affected in 

 the same way by another inhibitor. If the response to inhibition is measured 

 only at physiological levels (e.g., reflex activity, cardiac rate, intestinal 

 motility, or urine formation), the simple modification of function may alter 

 the response of this function to another agent, as it often does when pairs 

 of drugs are used. Relationships like this must be borne in mind in inter- 



(DNP)- 



FiG. 10-6. Effects of inhibitors on gastric acid 

 secretion in the presence of 2,4-dinitrophenol. The 

 control curve shows the effect of 2,4-dinitrophenol 

 alone and the curves for the two inhibitors show 

 the shift in the inflection point. (From Davenport 

 et ah, 1955.) 



preting the data from multiple inhibition but because of the complex be- 

 havior and the almost infinite possibilities of interplay, it is useless to at- 

 tempt a more quantitative treatment. More experimental data will be 

 necessary before theoretical advances may be made. 



