Defective function of membrane potential (psi) on sperm of infertile men.

Membrane potential across the plasma membrane (psi) of human sperm was determined by measuring the accumulation of triphenylmethylphosphonium (TPMP+). Washed sperm of fertile or infertile men were suspended, incubated in low-K+ and high-Na+ or high-K+ and low-Na+ medium, and allowed to take up the cation TPMP+ to a steady state (20 min at 37 degrees C). Under these conditions a psi of -75 +/- 6 mV was observed in sperm cells of fertile men, while in spermatozoa of idiopathic and asthenozoospermic infertile men, the psi was of 35 +/- 5 mV and 32 +/- 5 mV, respectively. Upon depolarization of the sperm membrane by K+, the transport system Na(+)-K+ in spermatozoa of idiopathic infertile men decreased 53 +/- 3.5%, while that in sperm cells asthenozoospermic men decreased 57 +/- 3% with respect to spermatozoa of fertile men. The results of these studies indicate their possible application to the diagnosis of male infertility.