Defective Function of Membrane Potential (Ψ) on Sperm of Infertile Men

Abstract

Membrane potential across the plasma membrane (Ψ) 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°C). Under these conditions a Ψ of −75 ± 6 mV was observed in sperm cells of fertile men, while in spermatozoa of idiopathic and astheno-zoospermic infertile men, the Ψ 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 of 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.

Key Words:

• fertility
• infertility
• membrane potential
• spermatozoa