Calcitriol differentially modulates mRNA encoding calcitriol receptors and calcium-binding protein 9 kDa in human...

Human intestinal mucosa consists of highly active epithelial cells in continual renewal and differentiation processes anatomically located at different portions of the villi. Besides its well recognized role in bone cell homeostasis, calcitriol has been attributed a role in cellular differentiation and proliferation in normal and cancerous cells. In this report, we show that in human fetal jejunum, depending upon the stage of gestation, calcitriol either enhances or decreases the levels of mRNA coding for its receptor. However, it up-regulates at all times those coding for the Vitamin D-dependent Calcium Binding Protein 9kDa. The present observations open interesting possibilities as to the role of calcitriol in the in utero human gut development and the control of colorectal cancers.