Zinc, magnesium and calcium in human seminal fluid: relations to other semen parameters and fertility

The effects of zinc, magnesium and calcium in seminal plasma on time-to-pre gnancy (TTP) in healthy couples, on conventional semen parameters and compu ter-assisted semen analysis (CASA) parameters were evaluated. The localizat ion of chelatable zinc ions in seminal plasma and spermatozoa were assessed by autometallography (AMG). Differences in chelatable zinc localization in samples with high and low total zinc were evaluated. Semen samples from 25 couples with short TTP and 25 couples with long TTP were subjected to conv entional semen analysis, CASA, zinc and magnesium measurements by inductive ly coupled plasma mass spectrometry, and calcium by flame atomic absorption spectrometry. The cations were strongly inter-correlated, but no correlati on with TTP or conventional semen parameters was found. Semen samples with high zinc concentrations exhibited statistically significant poorer motilit y assessed by the CASA parameters straight line velocity and linearity than samples with low zinc content. Calcium concentration also showed statistic ally significant differences for the same parameters, but the effect was re moved by entering zinc concentration into a multiple regression model. Seme n samples with high total zinc exhibited stronger staining of the seminal p lasma at AMG. It is suggested that high seminal zinc concentrations have a suppressing effect on progressive motility of the spermatozoa ('quality of movement'), but not on percentage of motile spermatozoa ('quantity of movem ent').