Calcitriol regulates the expression of the genes encoding the three key vitamin D₃ hydroxylases and the drug‐metabolizing enzyme <i>CYP3A4</i> in the human fetal intestine

Abstract

Collectively, the data illustrate that at mid-gestation 1,25(OH)2D3 is fully active in the modulation of all D3-hydroxylases in the human developing intestine. They also show that the detoxifying enzyme CYP3A4 is not only present along the intestinal tract but is also sensitive to 1,25(OH)2D3, indicating that the hormone may be a key element in intestinal development and in the maintenance of the intestinal mucosa integrity in the basal state and in response to damage-inducing agents.