Importance of Ca²⁺, K⁺ and Glucose in the Medium for Sperm Penetration through the Human Zona Pellucida

Abstract

HOSHI, K., TSUKIKAWA, S. and SATO, A. Importance of Ca²⁺, K⁺ and Glucose in the Medium for Sperm Penetration through the Human Zona Pellucida. Tohoku J. Exp. Med., 1991, 165 (2), 99-104-When salt-stored human oocytes were inseminated in the regular mBWW medium and examined 6hr later, the zonae of almost all of the oocytes were penetrated by spermatozoa. In contrast, none of zonae were penetrated when the oocytes were inseminated in either Ca²⁺-free, K⁺-free or glucose-free medium. The failure of zona penetration by spermatozoa in Ca²⁺-free and K⁺-free media is likely to be due to the inhibition of the acrosome reaction. Spermatozoa were unable to exhibit hyperactivated motility in glucose-free medium, suggesting that the failure of zona penetration in this medium is due, at least in part, to the inhibition of hyperactivated motility of spermatozoa.