Figure 5

Progesterone (P4)-stimulated Ca²⁺ entry in porcine sperm is dependent on CatSper channels. Sperm loaded with Fluo-4 were incubated in capacitating conditions at 39 °C. All groups were stimulated with 80 nM of P4. Sperm were treated with 0, 0.4, and 2 µM of NNC 55-0396, an inhibitor of CatSper channels. Fluorescence was measured at 0, 15, and 30 min. Inhibition of CatSper channels suppressed the normal rise in Ca²⁺ entry at 30 min stimulated by progesterone. This experiment was repeated three times. Different letters represent significant differences within a time point (p < 0.05).