Testosterone and gossypol effects on human sperm motility.

Area of Science:

• Reproductive biology
• Endocrinology
• Sperm physiology

Background:

• Seminal fluid testosterone concentrations are significantly higher in infertile males compared to fertile males.
• Understanding the role of testosterone and other substances on sperm function is crucial for male fertility research.

Purpose of the Study:

• To investigate the dose-dependent effects of testosterone on human sperm motility.
• To examine the influence of caffeine, dibutyryl cAMP, and various steroids on sperm function.
• To assess the impact of gossypol on sperm motility.

Main Methods:

• Turbidimetric analysis was employed to objectively measure sperm velocity and the percentage of rapidly moving sperm (%RM).
• Controlled experiments involved adding varying concentrations of testosterone, caffeine, dibutyryl cAMP, other steroids, and gossypol to semen samples.
• Sperm motility parameters were analyzed following the addition of these substances.

Main Results:

• Testosterone exhibited a dose-dependent inhibitory effect on sperm motility; 150 pg/100 microliter decreased motility by 36%, and 300 pg/100 microliter decreased it by 62%.
• Caffeine and dibutyryl cAMP demonstrated stimulatory effects on sperm motility and velocity, respectively.
• The stimulatory effects of caffeine and dibutyryl cAMP were abolished by the addition of 300 pg/100 microliter of testosterone.
• Gossypol significantly reduced sperm motility, with a 90% decrease observed at 100 pg/100 microliter.
• Other tested steroids (17 alpha-testosterone, 17 alpha-estradiol, 17 beta-estradiol, DHT, progesterone) had no significant effect on sperm motility.

Conclusions:

• Elevated seminal testosterone levels may contribute to male infertility by impairing sperm motility.
• Testosterone exerts an inhibitory effect on sperm velocity and movement.
• While caffeine and cAMP can enhance sperm function, their effects are counteracted by high testosterone concentrations.
• Gossypol is a potent inhibitor of sperm motility, highlighting its potential as a male contraceptive agent.