Postejaculatory zinc redistribution and sperm senescence.

Gel chromatographic analysis of the zinc distribution among different ligands in normal semen samples (N = 21) revealed that 11.6% of total zinc was associated with high molecular weight ligands (HMW greater than 80 kD), 26.9% with intermediate (IMW 3-80 kD) and 61.5% with low molecular weight ligands (LMW less than 3 kD). Split ejaculates (i.e., portions of mainly prostatic and seminal vesicular fluid collected separately) disclosed a difference in zinc binding properties between the different fractions. Thus, zinc in prostatic fluid was associated with LMW, while seminal vesicular fluid only contained HMW-bound zinc. Infertile men (N = 11) had a higher proportion of HMW-zinc than fertile men (N = 20) (16.1% vs. 11.8%, p less than 0.05), while there was no difference in zinc or fructose concentration between these two groups. When all semen samples were taken as a group and subdivided according to sperm motility, it was found that the proportion of HMW zinc was significantly higher in the low motility groups. Neither zinc, magnesium or fructose concentrations differed between samples with low and high sperm motility.