Figure 2. Glucose as energy substrate increases sperm beat frequency dramatically.

Sperm were continuously perifused for 20 min with buffer HS containing different energy substrates (10 mM lactate, 10 mM pyruvate and 5 mM glucose) as indicated. Beat frequency of single sperm was analyzed at t  = 0 min (white bars), t  = 20 min (gray bars) and t  = 60 min (black bars). Shown are mean values±s.e. of 35 cells of 3 animals. With no energy substrate present, flagellar beat declines significantly compared to t  = 0 min (***p<0.001). With glucose as the mere substrate, beat acceleration is significant compared to t  = 20 min and 60 min (***p<0.001) of all other substrate compositions.