ELEVATED NITRIC-OXIDE CONCENTRATION IN THE SEMINAL PLASMA OF INFERTILE MALES - NITRIC-OXIDE INHIBITS SPERM MOTILITY

PROBLEM: To evaluate the effect of nitric oxide in the seminal plasma on sperm motility. METHOD: Seminal plasma concentrations of NO2-, a st able end product of nitric oxide, of 108 males of infertile couples an d 15 proven fertile donors were measured and compared with spermatogra m parameters. Motile sperm was incubated with a nitric oxide-generatin g drug, sodium nitroprusside, for 6 hr in the absence or presence of o xyhemoglobin, an inhibitor of nitric oxide. RESULTS: The NO2- concentr ation in the seminal plasma was 6.58 +/- 0.56 mu M in 26 infertile mal es with leukocytospermia, 5.51 +/- 0.25 mu M in 82 infertile males wit hout leukocytospermia, and 3.91 +/- 0.16 mu M in 15 controls. There wa s a significant correlation between the NO2- con concentration and spe rm motility. Sodium nitroprusside reduced the sperm motility in a dose - and time-dependent manner and its reduction was completely inhibited by the addition of oxyhemoglobin. CONCLUSION: These findings indicate that nitric oxide concentration in the seminal plasma of infertile ma les is elevated and that nitric oxide is an inhibitor of sperm motion.