EFFECTS OF THYROXINE AND RELATED COMPOUNDS ON LIVER MITOCHONDRIA 1 3 



TABLE I 



Abolition of the Desaminothyroxine-inhibition of the Dinitrophenol- 

 Induced ATPase Activity of Liver Mitochondria by Atebrin 

 Experimental conditions as in Fi^- i. 



is also able to counteract to a remarkable extent the inhibitorv effects of 

 azide, atebrin and chlorpromazine in this reaction. This latter effect of 

 dithionite, which is illustrated in fig. S, was strongest in the case of azide, 



Nons 



Desaminotnyroxine, 10 M 



+ Azide, 25xlO"^M 



Chlorpromazine 75x10 M 



Atebrin, 75xlO'^M 



1 2 3 



Amytal , mM 



Fig. 7. Influence of azide, atebrin, chlorpromazine and desaminothyroxine 

 on the amytal sensitivity of the dinitrophenol-induced ATPase activity of rat liver 

 mitochondria. Experimental conditions as in Fig. i. 



followed by atebrin and chlorpromazine. In the case of the inhibition by 

 desaminothyroxine no counteraction bv dithionite could be observed. The 

 only other inhibitor of the Alg "' -activated ATPase which was found not 

 to respond to dithionite was pentachlorophenol. 



Finally, as briefly reported elsewhere ['^4], desaminothyroxine exhibited 



