Fig. 5.
Zn2+ and speract raise cAMP levels but only speract increases cGMP.
Concentration of cGMP (panel A) and cAMP (panel B) in spermatozoa diluted in 0CaSW with 1 mM IBMX were measured in the presence or absence of 100 nM Speract or 10 μM Zn2+ (0.07 nM free Zn2+). Also, the same measurements were performed in high K+ (50 mM) condition. The mean ± SE of three experiments with sperm from different animals with triplicate measurements were normalized against the control (the resting level of cyclic nucleotides). Asterisks (*) indicate statistically significant differences compared to controls (p < 0.05).