Figure 5.

Exogenous pyruvate increases glycolytic flux in human spermatozoa. Total endogenous levels of ¹³C₃ pyruvate and ¹³C₃ lactate derived from ¹³C₆ glucose were quantified by LC-MS and used as a measure of glycolytic flux. Spermatozoa were incubated under capacitating conditions for 120 min in the presence of 1 mM ¹³C₆ glucose (white bars) and a combination of 1 mM ¹³C₆ glucose and 1 mM ¹³C₁ pyruvate (black bars) under (A) normal oxygen levels and (B) in the presence of 10 mM NaCN to inhibit mitochondrial respiration. Data are presented as mean ± SEM from five separate experiments (n = 10). **P < 0.01 and ***P < 0.001.