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Background: Vitamin D has been well-known for its function in maintaining calcium and phosphorus homeostasis and promoting bone mineralization.
There is some evidence that in addition to sex steroid hormones, the classic regulators of human reproduction, vitamin D also modulates reproductive processes in women and men.
Aim: The aim of this review was to assess studies that evaluated the relationship between vitamin D and fertility in women and men as well as in animals.
Methods: We performed a systematic literature search in PubMed for relevant English language publications published until October 2011.
Results and Discussion:
• The vitamin D receptor (VDR) and vitamin D metabolizing enzymes are found in reproductive tissues of women and men.
• VDR knockout mice [with no vitamin D receptors] have significant gonadal insufficiency, decreased sperm count and motility, and histological abnormalities of testis, ovary and uterus.
• Moreover, we present evidence that vitamin D is involved in female reproduction including in-vitro fertilization (IVF) outcome (clinical pregnancy rates) and polycystic ovary syndrome (PCOS).
• In PCOS women, low 25-hydroxyvitamin D (25(OH)D) levels are associated with obesity, metabolic and endocrine disturbances, and vitamin D supplementation might improve menstrual frequency and metabolic disturbances in those women.
• Moreover, vitamin D might influence steroidogenesis of sex hormones (estradiol and progesterone) in healthy women
• And high 25(OH)D levels might be associated with endometriosis.
• In men, vitamin D is positively associated with semen quality and androgen status.
• Moreover, vitamin D treatment might increase testosterone levels. Testiculopathic men show low CYP21R expression, 25(OH)D levels and osteoporosis despite normal testosterone levels.
Source: European Journal of Endocrinology, Jan 24, 2012. By Lerchbaum E, Obermayer-Pietsch BR. Department of Internal Medicine, Divison of Endocrinology and Nuclear Medicine, Medical University Graz, Graz, Austria. [Email: firstname.lastname@example.org]