Regulation of CYP3A4 and CYP3A5 expression and modulation of “intracrine” metabolism of androgens in prostate cells by liganded vitamin D receptor

► The vitamin D hormone enhances CYP3A4 and CYP3A5 expression within prostate cells. ► Vitamin D regulation of CYP3A4 and CYP3A5 was directly mediated through VDR. ► Vitamin D treatment increased CYP3A enzyme activity with LNCaP cells. ► Elevated CYP3A function increased the intracellular inactivation of testosterone.