Elsevier

Metabolism

Volume 70, May 2017, Pages 125-132
Metabolism

Clinical Science
Glucocorticoids modulate human brown adipose tissue thermogenesis in vivo

https://doi.org/10.1016/j.metabol.2017.01.024Get rights and content
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Abstract

Introduction

Brown adipose tissue (BAT) is a thermogenic organ with substantial metabolic capacity and has important roles in the maintenance of body weight and metabolism. Regulation of BAT is primarily mediated through the β-adrenoceptor (β-AR) pathway. The in vivo endocrine regulation of this pathway in humans is unknown. The objective of our study was to assess the in vivo BAT temperature responses to acute glucocorticoid administration.

Methods

We studied 8 healthy male volunteers, not pre-selected for BAT presence or activity and without prior BAT cold-activation, on two occasions, following an infusion with hydrocortisone (0.2 mg.kg 1.min 1 for 14 h) and saline, respectively. Infusions were given in a randomized double-blind order. They underwent assessment of supraclavicular BAT temperature using infrared thermography following a mixed meal, and during β-AR stimulation with isoprenaline (25 ng.kg fat-free mass 1.min 1 for 60 min) in the fasting state.

Results

During hydrocortisone infusion, BAT temperature increased both under fasting basal conditions and during β-AR stimulation. We observed a BAT temperature threshold, which was not exceeded despite maximal β-AR activation. We conclude that BAT thermogenesis is present in humans under near-normal conditions. Glucocorticoids modulate BAT function, representing important physiological endocrine regulation of body temperature at times of acute stress.

Abbreviations

18FDG-PET/CT
18F-fluorodeoxyglucose-positron emission tomography/computed tomography
ATP
adenosine triphosphate
AUC
area under the curve
BAT
brown adipose tissue
CRF
clinical research facility
DXA
dual energy x-ray absorptiometry
HC
hydrocortisone
HOMA
homeostatic model assessment
ISO
isoprenaline
IT
infrared thermography
NEFA
non-esterified fatty acids
NIHR
National Institute for Health Research
NRES
National Research Ethics Service
REC
research ethics committee
tAUC
time-averaged area under the curve
TREF
reference point temperature
TSCR
supraclavicular temperature
UCP1
uncoupling protein 1
β-AR
beta adrenoceptor

Keywords

Brown adipose tissue
Glucocorticoids
Humans
Infrared thermography
Beta adrenoceptor

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