Figure 1.

Percentages of sperm with an intact plasma membrane (SYBR14⁺/PI⁻) following incubation with different concentrations of bicarbonate (Bic; 0 mM, 5 mM, 15 mM, 38 mM) and BSA (0, 5 mg/mL) for 300 min. The black arrow indicates the time at which 10 μg/mL of progesterone was added (i.e., 240 min) to induce acrosome exocytosis. Different superscripts (a–e) indicate significant differences (p < 0.05) between treatments within the same time point. Data are shown as mean ± SEM for 12 independent experiments.