62 G. W. SALISBURY 



croliters of gas or micrograms of substrate or end product consumed 

 or produced/ 10 s cells/hr) are means of 4-hr incubations in a sus- 

 pension medium of 0.9% NaCl at 37 °C. The first-hour values are 

 normally higher than the 4-hr means. 



It should be noted that the endogenous level of oxygen uptake 

 by epididymal spermatozoa is low. We have been unable to stimu- 

 late these cells to increased respiration as suggested by Lardy and 

 co-workers (1953) except by the addition of utilizable substrate 

 (Graves et al., 1959). When this is done, however, there is an im- 

 mediate increase in oxygen uptake. In order to collect routinely, 

 and at much less expense, a similar cell devoid of substrate, we have 

 evolved a technique for collection of ejaculated but nonmotile sper 

 matozoa directly into inhibitory diluents (Graves and Salisbury, 

 1959), the basis for which will be clear later in this discussion. These 

 cells have an aerobic endogenous metabolic rate similar to epididy- 

 mal spermatozoa and are designated as epididymal-like cells (ELC). 

 They respond to exogenous fructose by a slightly higher rate of O., 

 uptake and a somewhat lower rate of fructose uptake than do epi- 

 didymal spermatozoa. They respond to all available Meyerhof- 

 Embden intermediates and to lactate and acetate by sustained mo- 

 tility and an 2 uptake similar to that due to fructose but do not 

 utilize exogenous Krebs-cycle intermediates (Graves and Salisbury, 

 1960). 



Spermatozoa collected as semen are subjected to fructose and 

 other substrate immediately upon admixture with the secretions of 

 the accessory glands and until the cells are washed and removed from 

 them. Because of absorption of substrate during this variable period 

 before washing, endogenous respiration of washed ejaculated sper- 

 matozoa is nearly as high at first as in the presence of substrate, but 

 it decreases in rate as endogenous substrate is exhausted. The re- 

 sponse to added fructose is variable; an initial depression of respira- 

 tion often ensues because of the energy yield of glycolysis (Lardy 

 and Phillips, 1941), but as pyruvate enters, the oxidative scheme 

 again returns to normal levels (Lodge, 1960). 



Figure 1 shows the data of Olds and VanDemark (1957a) on the 

 oxygen consumption of spermatozoa in semen diluted 1:4 with a 

 saline solution containing additions from the fluids of the female 

 reproductive tract in comparison with that in saline alone. This 



