Modulation of Diet‐Induced Vitamin D Deficiency on Reproductive Hormones Secretion and Gene Expression in Adult Male Rats

Vitamin D deficiency is increasingly being recognized as a health concern, especially due to its role in male infertility. The present research was designed to systematically investigate the effects of dietary vitamin D on hormone secretion and gene expression at three levels of the male reproductive axis. Adult male rats ( n = 60) were housed in hygienic and well‐ventilated conditions in stainless steel cages at optimum temperature in an animal housing facility with 12 h light/dark cycle and were randomly divided into three equal groups. The control group was fed on a standard rodent diet. The vitamin D deficient (VDD) group was fed a VDD diet, and the third group (VDCP) was maintained on a VDD diet, but the feed was supplemented with calcium and phosphate. After 60 days of feeding, blood samples were obtained for hormone assays, and the animals were sacrificed. Hypothalamic, pituitary glands, and testicular tissues were obtained for real‐time polymerase chain reaction (RT‐PCR). The hypothalamic GnRH content was significantly decreased ( p < 0.05) in VDD and VDCP groups. FSH and LH levels were significantly decreased ( p < 0.05) in the VDD group. In the VDD group, RT‐PCR showed significant downregulation ( p < 0.05) of GnRH, FSH, and LH mRNA expression. The inhibin B was significantly reduced in both VDD and VDCP groups ( p < 0.05). VDD diet affected the reproductive hormones release and mRNA expression of GnRH in the hypothalamus, FSH, LH in the pituitary, and inhibin B in testicular tissues showing modulating effects on synthesis/release of these hormones.