Effects of seminal plasma from normal and asthenozoospermic men on the progressive motility of washed human sperm.

Human seminal plasma stimulated the progressive motility of human sperm in a dose- and time-related manner. Serum exhibited a similar capacity for stimulation. Seminal plasma from different normozoospermic men showed marked variation in its capacity to stimulate sperm motility. The stimulatory effect was maintained after heat-treatment, indicating the action of a low molecular weight substance or metal ion. No differences could be observed in the capacity for stimulation between seminal plasma from normozoospermic (n = 23) and asthenozoospermic (n = 22) men, when tested at the same dilution and under identical conditions. It is concluded that in general, differences in seminal plasma composition cannot account for the reduced sperm motility in asthenozoospermic men. Furthermore, the stimulatory effects of seminal plasma may be a property shared by other biological fluids.