268 HENRY LARDY 



Lardy : We obtained aurovertin very recently. Of a large number of ATP-ase 

 stimulations which we have tested including arsenate all are inhibited by oligo- 

 mycin but we haven't tested them all with aurovertin. In addition to arsenate, we 

 haven't tested dicoumarol on aurovertin yet. 



HoLLUNGER : In a study of the effect of guanidine on oxidative phosphorylation 

 [Acta Pharmacol, et Toxicol. ll, Suppl. i (1Q55)] I came to the conclusion that 

 guanidine decreased the respiration of mitochondria by inhibiting reactions con- 

 necting electron transport and ATP-generation. As Dr. Lardy now suggests the 

 same point of attack for oligomycin it is perhaps of some interest to note in con- 

 nection with Dr. Estabrook's question that guanidine inhibits the arsenate- 

 stimulated respiration of mitochondria. 



Lardy: The experiments we have done with oligomycin parallel exactly 

 those of Dr. Hollunger, and the compounds behave very much alike. However, 

 there are discrepancies, e.g. endogenous ATP-ase is depressed by guanidine but 

 DNP-stimulated ATP-ase is not completely depressed. 



