IONIC AND OSMOTIC CONDITIONS 83 



spermatozoa do not glycolyze fructose in a citrate bicarbonate dil- 

 uent under N 2 , but do so when the gas phase contains CO., . As the 

 /;CO L , is increased above 5%, the typical inhibition of anaerobic 

 glycolysis by C0 2 occurs. 



SUMMARY 



The mammalian reproductive tract fluids contain many compo- 

 nents, some of which exercise the control responsible for the vary- 

 ing degrees of motility and metabolic activity observed for bull 

 spermatozoa at various levels of the male and female reproductive 

 tracts. Some of the components responsible for metabolic control, as 

 judged by their in vitro influence on aerobic and anaerobic meta- 

 bolic behavior of bull spermatozoa, are the presence or absence of 

 substrate; the equivalent molal concentration of the total compo- 

 nents; the varying amounts and relative concentrations of the cations 

 making up the bulk of the mineral content of semen, sodium, po- 

 tassium, and calcium; the concentration of hydrogen ions; the nature 

 of and the relative concentration of some anions; and the partial 

 pressure of oxygen and carbon dioxide. From these studies there 

 emerges evidence of physiological metabolic control of spermatozoa 

 which should lead to a better understanding of one phase of the re- 

 markable reproductive process, and which may be applicable to other 

 tissues as well. 



Acknowledgments. The author of this paper has been aided in its 

 preparation by his colleague, Dr. J. R. Lodge, to whom the debt is ac- 

 knowledged with appreciation, and in its substance by permission from 

 Professor N. L. VanDemark and Mr. F. D. Bartlett, Jr., and Professor 

 Lodge, and Mr. C. N. Graves to present some hitherto unpublished data. 



REFERENCES 



Anderson, J. 1947. Some factors affecting the pH change in bull semen. 

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Bernstein, A. D., and A. V. Beskhlebnov. 1937. The effect of the active re- 

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Bishop, D. W. 1956. Metabolic conditions within the oviduct of the rabbit. 

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Bishop, D. W. 1958. Mammalian sperm cell models reactivated by ATP. 

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