Open Access18F-FDG uptake in the colon is modulated by metformin but not associated with core body temperature and energy expenditure
Author(s) -
Lonneke Bahler,
F. Holleman,
Man Wai Chan,
Jan Booij,
J. B. L. Hoekstra,
Hein J. Verberne
Publication year - 2017
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0176242
Subject(s) - metformin , medicine , energy expenditure , endocrinology , core (optical fiber) , overweight , glucose uptake , fluorodeoxyglucose , weight loss , positron emission tomography , obesity , diabetes mellitus , nuclear medicine , insulin , materials science , composite material
Purpose Physiological colonic 18 F-fluorodeoxyglucose ( 18 F-FDG) uptake is a frequent finding on 18 F-FDG positron emission tomography computed tomography (PET-CT). Interestingly, metformin, a glucose lowering drug associated with moderate weight loss, is also associated with an increased colonic 18 F-FDG uptake. Consequently, increased colonic glucose use might partly explain the weight losing effect of metformin when this results in an increased energy expenditure and/or core body temperature. Therefore, we aimed to determine whether metformin modifies the metabolic activity of the colon by increasing glucose uptake. Methods In this open label, non-randomized, prospective mechanistic study, we included eight lean and eight overweight males. We measured colonic 18 F-FDG uptake on PET-CT, energy expenditure and core body temperature before and after the use of metformin. The maximal colonic 18 F-FDG uptake was measured in 5 separate segments (caecum, colon ascendens,—transversum,—descendens and sigmoid). Results The maximal colonic 18 F-FDG uptake increased significantly in all separate segments after the use of metformin. There was no significant difference in energy expenditure or core body temperature after the use of metformin. There was no correlation between maximal colonic 18 F-FDG uptake and energy expenditure or core body temperature. Conclusion Metformin significantly increases colonic 18 F-FDG uptake, but this increased uptake is not associated with an increase in energy expenditure or core body temperature. Although the colon might be an important site of the glucose plasma lowering actions of metformin, this mechanism of action does not explain directly any associated weight loss.