IONIC AND OSMOTIC CONDITIONS 



67 



<r 8 



150 280 400 



OSMOTIC PRESSURE - MILLIOSMOLES 



Fig. 3. Effect of osmotic pressure (milliosmole concentration) produced 

 by NaCl or KC1 on aerobic metabolism of spermatozoa in semen. Number 

 of sperm samples, n, equals 10 (Lodge and Salisbury, 1960). 



tration to the NaCl (Lodge and Salisbury, 1960) are presented in 

 the second curve shown in Fig. 3. These two curves show the differ- 

 ence in metabolic response of spermatozoa to identical milliosmole 

 concentrations of the two major monovalent cations in reproductive 

 tract fluids and semen. The primary effects of osmotic pressure 

 whether exerted by the electrolytes of NaCl or KC1 are the same, 

 optimum oxygen consumption and optimum aerobic carbohydrate 

 uptake occurring at an osmotic pressure isotonic with seminal plasma. 

 However, the level of metabolic response in the presence of the Na+ 

 and K+ is quite different, the K+ exerting a marked inhibitory ef- 

 fect on respiration and on lactic acid accumulation, especially at 

 the osmotic pressure exerted by 280 milliosmoles. Fructose uptake 

 was greater in the presence of K + . While the motility in NaCl was 

 optimum, it was markedly inhibited by KC1, so that at the end of the 

 experiments the spermatozoa in KC1 had to be diluted with NaCl to 

 determine that they actually had survived the experiments. 



In hi hi I ion by Phosphate. Figure 4 gives the oxygen uptake re- 

 sults of an experiment (Lodge and Salisbury, 1960) with the same 

 ten semen ejaculates in which the effects of the same variations in 

 osmotic pressure are again produced by the monovalent cations, but 

 this time the anion is not the innocuous CI - , but the P0 4 at 



