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Nitric oxide synthase activity in human seminal plasma
A Zini1, M K O'Bryan, P N Schlegel
1James Buchanan Brady Foundation, Department of Urology, New York Presbyterian Hospital-Weill Medical College of Cornell University, New York, New York, USA.
Urology
|July 11, 2001
Summary
Human seminal plasma contains nitric oxide synthase (NOS) activity, suggesting a role for nitric oxide in sperm function. This enzyme activity was detected in most semen samples, but did not correlate with standard semen parameters.
Area of Science:
- Reproductive Biology
- Biochemistry
Background:
- Nitric oxide synthase (NOS) is present in the male reproductive tract.
- Nitric oxide (NO) is known to influence human sperm function in vitro.
Purpose of the Study:
- To determine if human seminal plasma has nitric oxide synthase (NOS) activity.
- To investigate the correlation between NOS activity and standard semen analysis parameters.
Main Methods:
- Collected semen samples from 30 men undergoing infertility evaluation.
- Assessed seminal plasma for calcium-dependent and calcium-independent NOS activity using [(3)H]L-arginine conversion.
- Measured arginine concentration and correlated NOS activity with sperm concentration, motility, and leukocyte count.
Main Results:
- NOS activity was detected in 28 out of 30 seminal plasma samples.
- Mean calcium-dependent NOS activity was 1.6 nmol/min/mL and calcium-independent NOS activity was 1.0 nmol/min/mL.
- No significant correlation was found between NOS activity and sperm parameters or leukocyte concentration.
Conclusions:
- Human seminal plasma exhibits nitric oxide synthase (NOS) activity.
- This finding supports a role for nitric oxide in in vivo sperm function.
- Seminal vesicles are suggested as a significant source of NOS activity in semen.