Vitamin D-1α-hydroxylase and vitamin D-24-hydroxylase mRNA studies in chickens.

A series of experiments were conducted to study the basal amounts of vitamin D-1α-hydroxylase and vitamin D-24-hydroxylase mRNA amounts in different organs and the effect of immune stimulation on 1α- and 24-hydroxylase mRNA amounts in chickens. At day of hatch, kidneys had an approximately 66-fold higher amount of 1α-hydroxylase and 550-fold higher amount of 24-hydroxylase mRNA, thigh and breast muscles had an approximately 20-fold higher amount of 1α-hydroxylase mRNA, and the thymus had an approximately 41-fold higher amount of 24-hydroxylase mRNA than the liver. An in vivo LPS injection did not alter the amount of 1α-hydroxylase mRNA in the breast muscle (P=0.60) or in the kidneys (P=0.39). An in vivo LPS injection decreased (P=0.01) the amount of 24-hydroxylase mRNA in the breast muscle at 3 d post-LPS injection. An in vivo LPS injection increased (P=0.01) the amount of 24-hydroxylase mRNA in the kidneys at 2, 3, and 6 d post-LPS injection. An in vitro stimulation altered amounts of 1α- (P=0.01) and 24-hydroxylase (P=0.04) mRNA in CD4+ cells. In conclusion, the distribution of 1α- and 24-hydroxylase mRNA amounts was similar to mammals, and an immune stimulation altered the amounts of 1α- and 24-hydroxylase mRNA in chickens.