Figure 7. . Model of intestinal calcium transport.

Figure 7.

Model of intestinal calcium transport. Calcium enters the microvillus of the intestinal epithelial cell through TRPV6 (previously known as CaT1) calcium channel. Within the microvillus calcium is bound to calmodulin (CaM) which is itself bound to brush border myosin I (BBMI). BBMI may facilitate the movement of the calcium/CaM complex into the terminal web where the calcium is picked up by calbindin (CaBP) and transported through the cytoplasm in endocytic vesicles. At the basolateral membrane the calcium is pumped out of the cell by the Ca-ATPase (PMCA1b). 1,25(OH)2D enhances intestinal calcium transport by inducing TRPV6, CaBP, and PMCAb as well as increasing the amount of CaM bound to BBMI in the brush border.

From: Vitamin D: Production, Metabolism and Mechanisms of Action

Cover of Endotext
Endotext [Internet].
Feingold KR, Anawalt B, Blackman MR, et al., editors.
South Dartmouth (MA): MDText.com, Inc.; 2000-.
Copyright © 2000-2024, MDText.com, Inc.

This electronic version has been made freely available under a Creative Commons (CC-BY-NC-ND) license. A copy of the license can be viewed at http://creativecommons.org/licenses/by-nc-nd/2.0/.

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.