Fig. 5. Impact of extracellular calcium on intracellular ATP. Spermatozoa (10x10⁶/ml) were incubated in either complete BWW (circles) or BWW -Ca²⁺ (squares). At the times indicated, 50 µl of the cell suspension was taken for measurement of ATP, as described in Materials and methods. The graph represents the data from three experiments performed in quadruplicate; ^*P<0.05.