Inhibition of hamster sperm acrosome reaction and fertilization by oligomycin, antimycin A, and rotenone

Abstract

Effects of respiratory inhibitors (oligomycin, antimycin A and rotenone) on hamster sperm acrosome reaction and fertilization were studied. Hamster spermatozoa were incubated in a mixture of a modified Tyrode's solution and heat-treated human serum in the presence and absence of inhibitors. Oligomycin (2.4 × 10⁻⁶ M), antimycin A (2.5 × 10⁻⁶ M) and rotenone (2.5 × 10⁻⁶ M) all reduced the incidence of the sperm acrosome reaction and fertilization without markedly affecting sperm motility. Antimycin A was the most effective in reducing the incidence of acrosome reaction. A reduction in the rate of fertilization was found in the presence of all of these respiratory inhibitors. The reduction in the incidence of acrosome reaction and fertilization by respiratory inhibitors implies an intimate relationship between high energy production (via respiration and oxidative phosphorylation) and capacitation and the acrosome reaction of spermatozoa. The necessity of oxidative metabolism for efficient capacitation and acrosome reaction of spermatozoa is suggested.