Functional Involvement of RFVT3/SLC52A3 in Intestinal Riboflavin Absorption.

In this study, we investigated the functional involvement of RFVT3 in riboflavin absorption using intestinal epithelial T84 cells and mouse small intestine. T84 cells expressed RFVT3 and conserved unidirectional riboflavin transport corresponding to intestinal absorption. Apical [(3)H]riboflavin uptake was pH-dependent in T84 cells. This uptake was not affected by Na(+) depletion at apical pH 6.0, although it was significantly decreased at apical pH 7.4. The [(3)H]riboflavin uptake from the apical side of T84 cells was prominently inhibited by the RFVT3 selective inhibitor, methylene blue, and significantly decreased by transfection of RFVT3-siRNA. In the gastrointestinal tract, RFVT3 was expressed in the jejunum and ileum. Mouse jejunal and ileal permeabilities of [(3)H]riboflavin were measured by the in situ closed loop method, and were significantly reduced by methylene blue. These results strongly suggest that RFVT3 would functionally be involved in riboflavin absorption in the apical membranes of intestinal epithelial cells. PMID: 24264046 [PubMed - as supplied by publisher]
Source: American Journal of Physiology. Gastrointestinal and Liver Physiology - Category: Physiology Authors: Tags: Am J Physiol Gastrointest Liver Physiol Source Type: research