60 G. W. SALISBURY 



revive. The nonmotile condition of the living spermatozoa in the 

 mammalian epididymis emphasizes this point, but the fact that im- 

 motile sperm cells were not always dead has not been sufficiently rec- 

 ognized in past investigations on sperm motility. 



Rebuilding of the limited ATP reserves of mammalian spermato- 

 zoa, upon the breakdown of which, with its yield of phosphate-bond 

 energy, the fibrillar contractions depend (Bishop, 1958), may occur 

 under anaerobic conditions only if the cell is supplied with a glyco- 

 lyzable substrate (Redenz, 1933), fructose, glucose, or mannose, and, 

 in the presence of oxygen, from the oxidation of a variety of sub- 

 strates. Glycolysis proceeds anaerobically much more rapidly (150 

 to 250 i*g fructose/ 10 s cells/hr at 37°C) than it does aerobically (see 

 Table I). By an ingenious use of electrodes inserted into the incu- 

 bation flask for measurement of impedance-change frequency Wal- 

 ton and Dott (1956) have been able to show that optimum motility 

 of the sperm cell population occurs in the presence of both a glyco- 

 lyzable substrate and oxygen. Thus, many of our investigations to 



Table I. Comparative aerobic metabolic activity of bovine spermatozoa 

 from the epididymis, epididymal-like sperm cells (ELC), spermatozoa in 

 semen, and sperm cells washed from semen with and without added fructose 

 at the same comparative concentration of spermatozoa 



_ 7 Aerobic 



Type of Spermatozoa / i/i m /L, —^fructose 



( M l/ 10 /hi) Gxg/10* hr) 



" Twenty-four samples (Graves et al., 1959). 



b Sixty samples of sperm cells collected into inhibitory diluents and washed (Grave 

 and Salisbury, 1959). 



c Several hundred samples, University of Illinois. 

 d Seventeen samples (Lodge and Salisbury, 1960). 

 e This 0> uptake occurred primarily during the first hour of incubation. 



