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Human sperm anatomy: ultrastructural localization of 1α,25‐dihydroxyvitamin D 3 receptor and its possible role in the human male gamete
Author(s) -
Aquila Saveria,
Guido Carmela,
Perrotta Ida,
Tripepi Sandro,
Nastro Alfonso,
Andò Sebastiano
Publication year - 2008
Publication title -
journal of anatomy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 118
eISSN - 1469-7580
pISSN - 0021-8782
DOI - 10.1111/j.1469-7580.2008.00975.x
Subject(s) - calcitriol receptor , sperm , capacitation , gamete , biology , medicine , endocrinology , receptor , microbiology and biotechnology , vitamin d and neurology , genetics
Previous studies have suggested that 1α,25‐dihydroxyvitamin D 3 [1,25(OH) 2 D 3 ] has a role in reproductive function. Gonadal insufficiencies were observed as a result of 1,25(OH) 2 D 3 deficiency and in 1,25(OH) 2 D 3 receptor (VDR) null mutant mice. To study human sperm anatomy at the molecular level, we first evaluated the ultrastructural localization of VDR by immunogold electron microscopy using a monoclonal antibody against amino acids 344–424 of human VDR, in normozoospermic samples. Intriguingly, VDR was associated predominantly with the cell nucleus. In fact, it is known that VDR is a transcription factor, and that in vitamin‐D‐depleted animals, VDR is largely localized in the cell nucleus. To assess the significance of VDR in the male gamete, we investigated the role of 1,25(OH) 2 D 3 /VDR in sperm survival and capacitation. Our results revealed that the action of 1,25(OH) 2 D 3 depended on its concentration because although lower doses induced cholesterol efflux, protein phosphorylation and sperm survival, a higher concentration seemed to be ineffective or did not show an increased effect. These results increase our knowledge of human sperm anatomy at the molecular level and suggest that 1,25(OH) 2 D 3 /VDR may have an important role in sperm survival and the acquisition of fertilizing ability.