Vitamin D Deficiency Affects the Sex Hormones and Testicular Function in Mice

This study aims to evaluate the genomic effects of vitamin D (VitD) on steroidogenesis, sperm structure, and function in mice models with artificially induced vitamin D deficiency (VDD), while maintaining calcium and phosphorus homeostasis. qRT-PCR was utilized to measure the steady-state RNA levels of key steroidogenic genes, including CYP11A1, CYP19A1, 17βHSDH1, 3βHSDV1, and CYP24A1, involved in VitD metabolism, in testicular extracts from mouse models with varying degrees of VDD severity. Estradiol, testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) levels were also assessed. Furthermore, testicular histomorphometric analysis and evaluation of sperm structural and functional parameters were conducted. The study reveals a linear decrease in the expression of monitored steroidogenic genes with increasing severity of VDD. Moreover, in cases of mild and moderate VDD, testicular extracts exhibited significantly reduced levels of LH, estradiol, and testosterone. VDD has substantial effects on testicular steroidogenesis, which directly impacts spermatogenesis, independent of its established role in calcium regulation. Consequently, the reduction in steroidogenesis due to VDD contributes to the diminished efficiency of testicular spermatogenesis in individuals experiencing VDD, a prevalent condition worldwide.