66 



W. SALISBURY 



~I73 231 290 348 406 



OSMOTIC PRESSURE - MILLIOSMOLS 



Fig. 2. Effect of osmotic pressure from combination of Na and K, cit- 

 rate and bicarbonate, on aerobic metabolism of washed spermatozoa. Num- 

 ber of sperm samples, n, equals 8 (Cragle and Salisbury, 1959). 



at 37 °C show very little effect of milliosmole concentration on oxy- 

 gen consumption or aerobic fructolysis. 



Response to Varying Osmotic Pressure Caused by Different Cations 



For optimum aerobic metabolism in these studies of the effect of 

 osmotic pressure, we next used 0.9% NaCl as the comparative sus- 

 pension medium, the salt concentration being varied as indicated 

 and the dilution ratio being 4 parts of medium to 1 part of semen or 

 washed cells. The final spermatozoan concentration was controlled 

 to from 1.5 to 3.5 X 10 8 cells/ml, and the substrate was seminal 

 fructose, its degradation products, or added fructose or glucose for 

 washed cells. 



Figure 3 gives the mean oxygen consumption results of one such 

 experiment with ten semen samples showing the effects of varying 

 concentrations of NaCl (Lodge and Salisbury, 1960). Both optimum 

 oxygen consumption and optimum aerobic glycolysis during the 3- 

 hour period at 37 °C occurred at a milliosmole concentration isos- 

 motic with seminal plasma exerting an osmotic pressure of about 

 280 milliosmoles. 



Inhibition by Potassium. On the other hand, the oxygen uptake 

 results for parts of the same semen samples suspended 1 : 4 in a me- 

 dium composed entirely of KC1 at comparable milliosmole concen- 



