Ionic and Osmotic Conditions in 

 Relation to Metabolic Control* 



G. W. SALISBURY 



Department of Dairy Science, University of Illinois, Urbana 



In their natural habitat of the male or female reproductive tract 

 the energy expenditures of mammalian spermatozoa are conserved 

 or expended, inhibited or stimulated, by the local environment. All 

 such controls have undoubtedly evolved as efficient means of assur- 

 ing performance of ultimate function, fertilization. This process has 

 produced a reproductive cell of amazing versatility and adaptability. 



ENERGY EXPENDITURE BY BULL SPERMATOZOA 



In general, energy may be expended by spermatozoa which does 

 not result in either motility or the rebuilding of energy-rich adeno- 

 sine triphosphate (ATP) reserves (the uncoupling of oxidative phos- 

 phorylation by 2,4-dinitrophenol (DNP) (Gassner and Hopwood, 

 1955; Melrose and Terner, 1951, 1952, 1953; Terner, 1957) or the 

 continuance of active oxidation after death of the cells (Kofoed- 

 Johnsen and Mann, 1954; Salisbury and YanDemark, 1957a) are 

 cases in point); but, motility does not occur unless energy is ex- 

 pended. Where the tools available are not adequate to measure their 

 metabolic exchange, the extent and degree of motility by the sper- 

 matozoan population in situ afford a ready visual certification that 

 metabolic exchange is taking place. 



Unfortunately, spermatozoa that have once been actively motile 

 but have lost that capacity owing to some inhibitory treatment may 

 sometimes be considered as dead cells. A dead sperm cell cannot be 

 stimulated to motility. A nonmotile spermatozoon is not always a 

 dead one, but may be an inhibited one without a proper chance to 



* The work reported has been supported in part by a grant from the Rocke- 

 feller Foundation. 



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