OXIDATIVE AND BIOSYNTHETIC REACTIONS 93 



Table V. Oxidation of glucose, pyruvate, and acetate by spermatozoa" 



"Metabolic rate Uxl/lO 10 spermatozoa/hrj 



a few words will be said about some measurements of the oxidative 

 activity of spermatozoa of other species. 



Table V lists determinations of the rates of oxidation of glucose, 

 pyruvate, and acetate in spermatozoa of the bull, man, and fish. The 

 main difficulty in working with human semen is its small volume 

 and its low sperm count. Its average volume is 3.5 ml, and its count 

 is of the order of 100 million cells/ml. Bull semen has a count ten 

 times as high and larger volumes are usually available. Fish sperm 

 can be obtained in large amounts, but the spawning season is rela- 

 tively short. 



The sperm suspensions were centrifuged and resuspended in Krebs 

 saline. The respiration was measured in the Warburg apparatus, but 

 no readings were obtained in the case of human spermatozoa. Never- 

 theless, by the more sensitive isotope technique it could be shown 

 that human spermatozoa oxidized glucose, acetate, and pyruvate to 

 CO, and water. This seems to be unequivocal evidence that human 

 spermatozoa have an aerobic metabolism (Terner, 1960). 



The metabolic rate of bull spermatozoa was by far the highest of 

 those listed here. Although it is customary to use the Z notation 

 (microliters per 10 s spermatozoa per hour), the metabolic rates are in 

 Table V given as microliters per 10 10 spermatozoa per hour. 



The oxidation rates in human and fish spermatozoa are of a simi- 

 lar order of magnitude, whereas the metabolic activity of bull sper- 

 matozoa is much greater. In bull and fish spermatozoa, the rate of 

 oxidation of pyruvate stands out as the highest, but whereas the mam- 

 malian spermatozoa oxidize glucose quite well, fish spermatozoa 



