Posted 12/19/2020 2:27 PM (GMT -5)
That link goes to one heck of a write up, a little more than my reading brain can handle at the moment.
The summary at the bottom makes some sense:
["Finally, the reason why these genes are controlled by VDR is unclear. CYP2B6, CYP2C9, and CYP3A4 have not been shown to be involved in the metabolism of vitamin D (49-51). However, it has been observed that prolonged therapy with rifampicin can cause vitamin D deficiency (52). In eight healthy subjects, rifampicin treatment reduced circulating levels of 25-hydroxyvitamin D and 1α,25-(OH)2D3 by 34 and 23%, respectively. In addition, rifampicin and phenobarbital are two of the drugs most frequently associated with osteomalacia, a metabolic bone disease characterized by a defect of bone mineralization frequently due to an alteration of vitamin D metabolism (53). This suggests that CAR and/or PXR might be involved in the control of genes involved in vitamin D synthesis or catabolism. "]