Characterization of the Ca2+ Channels Involved in the Progesterone-Induced Ca2+ Influx and Acrosome Reaction (AR) in Human Spermatozoa

Abstract

There is evidence that intracellular Ca2+ concentration plays significant roles in sperm function such as motility and acrosome reaction. Many calcium channels have been identified in the plasma membrane of sperm. Progesterone (P4) stimulates Ca2+ influx and acrosome reaction in human spermatozoa. The effects of three multivalent calcium channel blockers, cadmium, lanthanum and nickel on the P4-induced Ca2+ influx and AR in human spermatozoa were determined. Pretreatment with the blockers before P4 challenge decreased the amplitude of the transient of P4- induced Ca2+ influx in a dose dependent manner. Lanthanum was the most potent. The results also suggest that Cd2+ permeates the sperm cell membrane mainly through the same pathways of Ca2+ influx. All three calcium channel blockers significantly (p<0.05) inhibited the P4-induced AR. These
data suggest that L-type calcium channels may be involved in the P4-induced Ca2+ influx and the ability of the hormone to induce AR is not solely dependent on the amplitude of the transient of Ca2+ influx it generates

Journal of the Ghana Science Association Vol. 10 (2) 2008: pp. 166-177