RESPIRATION AND OXIDATIVE PHOSPHORYLATION 



123 



likely, as suggested by certain investigations on other types of ma- 

 terial (Chance, 1955; Clifton, 1946). 



Thus, in Spisula as in dog spermatozoa, inhibition of motility by 

 azide cannot be directly attributed to its inhibitory effect on respira- 

 tion. Its apparent action as an uncoupler and as a glycolytic poison 

 must be taken into account. 



Amytal action on motility of dog spermatozoa parallels its inhibi- 

 tory effect on respiration; 80 to 90% of respiration is Amytal-sensi- 

 tive and motility is diminished considerably at 10 mM Amytal con- 

 centration (Fig. 15). In Spisula sperm where respiration is 50% 

 Amytal-sensitive, motility is still normal at 10 mM Amytal and is 

 affected only by higher doses (Fig. 16). In both types of spermatozoa, 

 exogenous succinate failed to reverse partial inhibition of respira- 

 tion, as it did in bull sperm, owing to a lack of permeability to this 

 substrate. In any case, oxidation of endogenous succinate appears to 



100 



1 1 — i » i i 1 1 1 1 1 — i i i i 1 1 | 1 r 



full 

 mo I - . 



ma x. inn. — » 



no mot 



•^v 



&+-• — • 



J L_L 



j! 



■ ■ i i i ■ 1 1 i 



0.1 1. 10 mM azide 



Fig. 14. Effect of azide on exogenous respiration of dog spermatozoa. 

 Cells in seminal fluid with GG, pH 7.3. Z 02 of 11. Within the frame, pro- 

 gressive inhibition of motility. 



