Presence of the vitamin D inactivating enzyme CYP24A1 in human sperm and prediction of the success of intrauterine insemination: A prospective study.

Male fertility is routinely evaluated by semen analysis, although semen quality variables such as; sperm count, motility and morphology have low predictive value for spontaneous pregnancies and fertility treatment outcomes. Vitamin D has been suggested to be beneficial for male reproduction. The vitamin D receptor and the vitamin D inactivating enzyme CYP24A1 are co-expressed in high quality sperm.

Selection of High-Quality Spermatozoa May Be Promoted by Activated Vitamin D in the Woman.

Context: The vitamin D receptor (VDR) and enzymes involved in activation (CYP2R1, CYP27B1) and inactivation (CYP24A1) of vitamin D are expressed in ovary, testes, and spermatozoa.

Objective: Determine responsiveness to 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] in spermatozoa from normal and infertile men, and identify the site of exposure and how 1,25(OH)2D3 influences sperm function.

Design: Spermatozoa expressing VDR, CYP2R1, CYP27B1, and CYP24A1 were analyzed in normal and infertile men.