72 G. W. SALISBURY 



Table III. Effect of initial pH of saline-phosphate diluent on respiration 

 and aerobic fructolysis of bovine semen in the presence and absence of met- 

 abolic CCV- 6 



a n, the number of semen samples, equals 12. 

 b Salisbury and Kinney (1957). 



rapidly oxidized. Motility ceased at low pH, but the exact pH at 

 which this occurred varied from pH 6.0 for the acetate to pH 4.5 for 

 the phosphate and tartrate buffers. Recovery on raising the pH varied 

 also, being nearly complete in the acetate and least in the phosphate 

 (Bernstein and Baskhlebnov, 1937). 



Differential Response of Respiration and Aerobic Glycolysis to pH 

 Variations. Some of our results of the effect of pH on aerobic meta- 

 bolic activity of bull spermatozoa are shown in Tables III-V and 

 Figs. 6 and 7. In the first of these, Table III, is shown the effect on 

 aerobic metabolism of pH variations of from 5 to 8 (Salisbury and 

 Kinney, 1957). The pH levels were due to differing amounts of so- 

 dium monohydrogen and sodium di hydrogen phosphate as one half 

 of a saline-phosphate diluent with a milliosmole concentration of 

 about 290. Respiration was minimal at pH 6 and 7 with a maximum 

 at pH 8. The overall effect was curvilinear with a highly significant 

 pH level by sample interaction; for one or another of the thirty-one 

 semen samples maximum respiration occurred at every one of the 

 pH levels. Note, however, that the effects of pH on aerobic glycol- 

 ysis were linear, additive, and of substantial quantity per pH unit. 

 Note, also, that both fructose utilization and lactic acid accumula- 

 tion were highly significantly increased by the presence of the evolved 

 respiratory C0 2 in the reaction flasks. 



Figure 6 shows the effect of similar variations in pH in a citrate- 

 bicarbonate buffer on the aerobic metabolism of washed ejaculated 

 spermatozoa of the bull (Cragle and Salisbury, 1959). Again the in- 

 fluence on respiration is curvilinear, but is maximized in the inter- 



