The effect of zinc ions on fertilization of mouse ova in vitro

The fertilization rate of mouse gametes in a Krebs-Ringer bicarbonate medium was 60%. The rate fell to 0% when 250 micron-ZnCl2 was added, but MgCl2, CaCl2, MnCl2, FeCl2, and CuCl2 (each at 250 micron) had no effect. The inhibitory effect of Zn2+ was not evident if the spermatozoa or eggs were preincubated with Zn2+ or if previously capacitated spermatozoa were used. The Zn2+ is thought to act by interference with capacitation.