Format

Send to

Choose Destination
Diabetes Obes Metab. 2016 Jan;18(1):72-81. doi: 10.1111/dom.12585. Epub 2015 Nov 20.

Glucagon increases energy expenditure independently of brown adipose tissue activation in humans.

Author information

1
Section of Investigative Medicine, Hammersmith Hospital, Imperial College London, London, UK.
2
Imanova Centre for Imaging Sciences, Hammersmith Hospital, London, UK.
3
Department of Computing, Imperial College London, London, UK.
4
Department of Radiology, Imperial College NHS Healthcare Trust, London, UK.
5
Centre for Neuroimaging Sciences, King's College, London, UK.
6
Division of Brain Sciences, Imperial College London, London, UK.
7
Early Life Research Group, Academic Division of Child Health, Obsterics and Gynaecology, School of Medicine, Queen's Medical Centre, University Hospital, The University of Nottingham, Nottingham, UK.

Abstract

AIMS:

To investigate, for a given energy expenditure (EE) rise, the differential effects of glucagon infusion and cold exposure on brown adipose tissue (BAT) activation in humans.

METHODS:

Indirect calorimetry and supraclavicular thermography was performed in 11 healthy male volunteers before and after: cold exposure; glucagon infusion (at 23 °C); and vehicle infusion (at 23 °C). All volunteers underwent (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET)/CT scanning with cold exposure. Subjects with cold-induced BAT activation on (18)F-FDG PET/CT (n = 8) underwent a randomly allocated second (18)F-FDG PET/CT scan (at 23 °C), either with glucagon infusion (n = 4) or vehicle infusion (n = 4).

RESULTS:

We observed that EE increased by 14% after cold exposure and by 15% after glucagon infusion (50 ng/kg/min; p < 0.05 vs control for both). Cold exposure produced an increase in neck temperature (+0.44 °C; p < 0.001 vs control), but glucagon infusion did not alter neck temperature. In subjects with a cold-induced increase in the metabolic activity of supraclavicular BAT on (18)F-FDG PET/CT, a significant rise in the metabolic activity of BAT after glucagon infusion was not detected. Cold exposure increased sympathetic activation, as measured by circulating norepinephrine levels, but glucagon infusion did not.

CONCLUSIONS:

Glucagon increases EE by a similar magnitude compared with cold activation, but independently of BAT thermogenesis. This finding is of importance for the development of safe treatments for obesity through upregulation of EE.

KEYWORDS:

18F-FDG PET/CT; energy expenditure; glucagon; human brown adipose tissue; thermal imaging

PMID:
26434748
PMCID:
PMC4710848
DOI:
10.1111/dom.12585
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center