Open AccessFructose transporters GLUT5 and GLUT2 expression in adult patients with fructose intolerance
Author(s) -
Wilder-Smith Clive H,
Li Xinhua,
Ho Sherry SY,
Leong Sai Mun,
Wong Reuben K,
Koay Evelyn SC,
Ferraris Ronaldo P
Publication year - 2014
Publication title -
ueg journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.667
H-Index - 35
eISSN - 2050-6414
pISSN - 2050-6406
DOI - 10.1177/2050640613505279
Subject(s) - glut2 , fructose , medicine , endocrinology , interquartile range , glucose transporter , biochemistry , biology , insulin
Background Gastrointestinal symptoms and malabsorption following fructose ingestion (fructose intolerance) are common in functional gastrointestinal disorders (FGID). The underlying mechanism is unclear, but is hypothesized to be related an abnormality of intestinal fructose transporter proteins. Objective To assess the expression of the main intestinal fructose transporter proteins, glucose transport protein 5 (GLUT5) and 2 (GLUT2), in FGID. Methods The expression of GLUT5 and GLUT2 protein and mRNA in small intestinal biopsy tissue was investigated using real‐time reverse‐transcription PCR and Western immunoblotting in 11 adults with FGID and fructose intolerance ascertained by breath testing and in 15 controls. Results Median expression levels of GLUT5 mRNA normalized to beta‐actin were 0.18 (interquartile range, IQR, 0.13–0.21) in patients and 0.17 (IQR 0.12–0.19) in controls ( p > 0.05). Respective levels of GLUT2 mRNA were 0.26 (IQR 0.20–0.31) and 0.26 (IQR 0.19–0.31) ( p > 0.05). Median expression levels of GLUT5 protein normalized to alpha‐tubulin were 0.95 (IQR 0.52–1.68) in patients and 0.95 (IQR 0.59–1.15) in controls ( p > 0.05). Respective protein expression levels for GLUT2 were 1.56 (IQR 1.06–2.14) and 1.35 (IQR 0.96–1.79) ( p > 0.05). Conclusions Human fructose intolerance may not be associated with marked changes in GLUT5 and GLUT2 expression. Replication of these results in a larger subject group, including measures of transporter activation and membrane and subcellular localization, is warranted.