Possible influence of vitamin D on male reproduction.
Vitamin D is a versatile signaling molecule with an established role in the regulation of calcium homeostasis and bone health. In recent years the spectrum of vitamin D target organs has expanded and a reproductive role is supported by the presence of the vitamin D receptor (VDR) and the vitamin D metabolizing enzymes in the gonads, reproductive tract, and human spermatozoa. Interestingly, expression levels of VDR and the vitamin D inactivating enzyme CYP24A1 in human spermatozoa serve as positive predictive markers of semen quality and are higher expressed in spermatozoa from normal than infertile men. VDR mediates a non-genomic increase in intracellular calcium concentration, sperm motility, and induces the acrosome reaction. Furthermore, functional animal model studies have shown that vitamin D is important for sex steroid production, estrogen signaling, and semen quality. Cross-sectional clinical studies have supported the notion of a positive association between serum 25-hydroxyvitamin D (25-OHD) level and semen quality in both fertile and infertile men. However, it remains to be determined whether this association reflects a causal effect. The VDR is ubiquitously expressed and activated vitamin D is a regulator of insulin, aromatase, and osteocalcin. Hence, it is plausible that the influence of vitamin D on gonadal function may be mediated indirectly through other vitamin D regulated endocrine factors. Recent studies have indicated that vitamin D supplementation may be beneficial for couples in need of assisted reproductive techniques as high serum vitamin D levels were found to be associated with a higher chance of achieving pregnancy. Randomized clinical trials are needed to determine whether systemic changes in vitamin D metabolites can influence semen quality, fertility, and sex steroid production in infertile men. In this review known and possible future implications of vitamin D in human male reproduction function will be discussed.
University Department of Growth and Reproduction and International Research and Research Training Centre in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen, Denmark; Division of Bone and Mineral Research, Harvard School of Dental Medicine, Boston, MA, USA.
Ida Marie
IM
Boisen
University Department of Growth and Reproduction and International Research and Research Training Centre in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen, Denmark; Division of Bone and Mineral Research, Harvard School of Dental Medicine, Boston, MA, USA.
Lasse
L
Bøllehuus Hansen
University Department of Growth and Reproduction and International Research and Research Training Centre in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen, Denmark; Division of Bone and Mineral Research, Harvard School of Dental Medicine, Boston, MA, USA.
Li Juel
LJ
Mortensen
Division of Bone and Mineral Research, Harvard School of Dental Medicine, Boston, MA, USA.
Beate
B
Lanske
University Department of Growth and Reproduction and International Research and Research Training Centre in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen, Denmark.
Anders
A
Juul
University Department of Growth and Reproduction and International Research and Research Training Centre in Endocrine Disruption of Male Reproduction and Child Health (EDMaRC), Rigshospitalet, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 9, DK-2100 Copenhagen, Denmark; Division of Bone and Mineral Research, Harvard School of Dental Medicine, Boston, MA, USA. Electronic address: Blombergjensen@gmail.com.
Martin
M
Blomberg Jensen
D000818:Animals; D001141:Aromatase / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism; D006801:Humans; D008297:Male; D018167:Receptors, Calcitriol / Q000378:metabolism; D012098:Reproduction; D055101:Semen Analysis; D015398:Signal Transduction; D013094:Spermatozoa / Q000166:cytology* / Q000378:metabolism; D013736:Testicular Neoplasms / Q000378:metabolism; D013737:Testis / Q000166:cytology / Q000502:physiology*; D014807:Vitamin D / Q000378:metabolism*
D018167:Receptors, Calcitriol; C579457:VDR protein, human; D014807:Vitamin D; D004958:Estradiol; D001141:Aromatase
Calcium; Fertility; Reproduction; Sex hormones; Vitamin D