title: Vitamin D and male reproduction.
abstract: Vitamin D is a versatile signalling molecule with a well-established role in the regulation of calcium homeostasis and bone health. The spectrum of vitamin D target organs has expanded and the reproductive role of vitamin D is highlighted by expression of the vitamin D receptor (VDR) and enzymes that metabolize vitamin D in testis, male reproductive tract and human spermatozoa. The expression levels of VDR and CYP24A1 in human spermatozoa serve as positive predictive markers of semen quality, and VDR mediates a nongenomic increase in intracellular calcium concentration that induces sperm motility. Interestingly, functional animal models show that vitamin D is important for estrogen signalling and sperm motility, while cross-sectional studies support the positive association between serum 25-hydroxyvitamin D level and sperm motility in both fertile and infertile men. Expression of VDR and enzymes that metabolize vitamin D in fetal testis indicates a yet unknown role during development, which may be extrapolated from invasive testicular germ cell tumours where 1α,25-dihydroxyvitamin D induces a mesodermal differentiation of the pluripotent testicular cancer cells. Taken together, vitamin D signalling has a positive effect on semen quality, increases estrogen responsiveness and differentiates germ cell tumours. Future studies are needed to determine when 1α,25-dihydroxyvitamin D acts in a paracrine manner and whether systemic changes, which are subject to pharmacological modulation, could influence male reproductive function.
authors.affiliation: University Department of Growth and Reproduction, Rigshospitalet, Section 5064, Blegdamsvej 9, 2100 Copenhagen, Denmark.
authors.forename: Martin
authors.initials: M
authors.lastname: Blomberg Jensen
mesh_terms: D000818:Animals; D005298:Fertility / Q000502:physiology*; D006801:Humans; D008297:Male; D018167:Receptors, Calcitriol / Q000378:metabolism*; D013094:Spermatozoa / Q000378:metabolism*; D013737:Testis / Q000378:metabolism*; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D018167:Receptors, Calcitriol; D014807:Vitamin D; C104450:25-hydroxyvitamin D