92 CHARLES TERNER 



Table IV. Effect of anaerobic glycolysis on decarboxylation of pyruvate" 



.,,, 00 2 



Addltlons Oil/10" spermatozoa/hr) 



None 8 . 3 



DNP 2.8 



Glucose 4 . 1 



Glucose, DNP 0.6 



Fluoride 8.7 



Fluoride, DNP 3.1 



Glucose, fluoride 5.9 



Glucose, fluoride, DNP 1.3 



"Washed spermatozoa incubated in phosphate saline at 37°; gas, 100% nitrogen; 

 l-C 14 -pyruvate (0.005M) in all vessels; glucose, 0.005A/; fluoride, 0.01M; DNP, 10~W; 

 incubation period, 75 min; sperm count, 9.1 X 10 8 /vessel. 



Before making this almost obvious conclusion, it was tested ex- 

 perimentally. Contrary to expectation, it was found that the decar- 

 boxylation of l-C 14 -pyruvate persisted in the presence of glucose. 

 When fluoride was added to minimize isotope dilution of the labeled 

 pyruvate by unlabeled pyruvate produced by glycolysis, there was 

 only 30% suppression of the decarboxylation of pyruvate (Table 

 IV). It seems that the dismutation system is powerful enough to com- 

 pete with the glyceraldehyde phosphate dehydrogenase system. And 

 it appears that even under anaerobic conditions, a part of the py- 

 ruvate derived from the glycolytic breakdown of fructose undergoes 

 dismutation producing lactate, CO. , and acetyl coenzyme A. The 

 production of acetyl coenzyme A under anaerobic conditions raises 

 the question of its utilization. In the absence of oxygen the acetyl 

 coenzyme A cannot be oxidized via the Krebs cycle. It may be simply 

 deacylated to acetate and coenzyme A, but a more interesting pos- 

 sibility is that acetyl coenzyme A serves as the starting point of bio- 

 synthetic reactions in spermatozoa under both aerobic and anaerobic 

 conditions. 



Biosynthesis in spermatozoa had been kept in mind for some time, 

 ever since the assumption was made, rightly or wrongly, that the in- 

 complete oxidation of pyruvate pointed in this direction (Melrose 

 and Terner, 1953). An attempt was made to investigate biosynthetic 

 reactions in bull spermatozoa, but before these results are described, 



