Effect of vitamin D metabolites and gene expression of vitamin D receptor, and 1-alpha-hydroxylase related to the sperm quality.

Vitamin D metabolites in blood and intracellular sperm 1,25- dihydroxycholecalciferol seem to exert beneficial effects on sperm motility and morphology. Regarding sperm quality these effects are more pronounced in the free and bioavailable 25OHD compared to the total 25OHD in blood. Higher expression of 1-α-hydroxylase likely leads to higher intracellular levels of 1,25- dihydroxycholecalciferol, which could contribute to sperm motility and morphology. Higher VDR expression may be a compensatory mechanism related to lower intracellular sperm 1,25- dihydroxycholecalciferol.