Stimulation of sperm progressive motility by organelles in human seminal plasma.

A simple method for objective determination of sperm progressive motility is described. Comparisons were made between results with this method and subjective grading of motility. Although congruence between the two methods was demonstrated, the subjective evaluation had obvious disadvantages. In suspensions of NaCl-washed spermatozoa, seminal plasma was required for progressive motility. Various isotonic salt solutions without seminal plasma were ineffective in this respect. Washed spermatozoa, however, were always motile in a medium consisting of pellet II, obtained from ultracentrifugation of human seminal plasma, thoroughly mixed with isotonic NaCl solution. The progressive sperm motility was two to three times as great in that medium as in seminal plasma mainly devoid of organelles. Magnesium, calcium and zinc ions, in the presence of seminal plasma, could exert stimulatory and inhibitory effects on sperm progressive motility, depending on the concentration of each divalent cation. Magnesium gave the greatest stimulatory and zinc the greatest inhibitory effect.