Fig. 2

Kinetics of different HCO₃⁻ concentrations on sperm protein kinase A substrates phosphorylation (pPKAs). Sperm were incubated for 1, 5, 15, 30 and 60 min in capacitating medium (TALP) containing 0 mmol/L (A), 5 mmol/L (C), 15 mmol/L (E) and 25 mmol/L (G) of HCO₃⁻ (4 replicates). In each blot a lane of spermatozoa incubated in PBS was included as non-capacitating control (NCAP). In 0 mmol/L (A) and 5 mmol/L blots (C) a lane for spermatozoa incubated in 25 mmol/L for 60 min was included as positive control. β-actin (β-act) or β-tubulin (β-tub) was used as loading control. Relative amount of semi-quantified signal for 0 mmol/L, 5 mmol/L, 15 mmol/L and 25 mmol/L blots are shown in graphics B, D, F and H, respectively. Results are shown as mean ± SEM. Different letters (a-c) indicate statistically significant differences (P < 0.05) between groups