Evidence that an ATPase functions in the maintenance of the acidic pH of the hamster sperm acrosome.
The hamster sperm acrosome exhibits a transmembrane proton concentration gradient (inside acidic). The gradient was dissipated by valinomycin and the proton ionophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) together, but not by either alone. Several anion transport inhibitors, when utilized in the presence of FCCP, also eliminated the proton gradient. These experiments demonstrate that a modified Donan-type equilibrium dependent upon selective permeability of membranes to protons has no role in maintenance of the acidic pH of the acrosome. N,N'-Dicyclohexylcarbodiimide and 4-chloro-7-nitrobenzofuran, inhibitors of the mitochondrial proton-translocating ATPase, dissipated the proton concentration gradient when FCCP was present. Oligomycin and ouabain had no effect, either in the presence or absence of FCCP. Our experimental evidence suggests that an ATP-dependent proton pump is functioning in the maintenance of the acidic pH of the hamster sperm acrosome.
D000177:Acrosome / Q000201:enzymology*; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D006224:Cricetinae; D006863:Hydrogen-Ion Concentration; D008297:Male; D009840:Oligomycins / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D011339:Probenecid / Q000494:pharmacology; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000201:enzymology*; D014634:Valinomycin / Q000494:pharmacology
D009840:Oligomycins; D014634:Valinomycin; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D010042:Ouabain; D000251:Adenosine Triphosphatases; D011339:Probenecid