Ephedrine activates brown adipose tissue in lean but not obese humans.
OBJECTIVE
Brown adipose tissue (BAT) activation increases energy consumption and may help in the treatment of obesity. Cold exposure is the main physiological stimulus for BAT thermogenesis and the sympathetic nervous system, which innervates BAT, is essential in this process. However, cold-induced BAT activation is impaired in obese humans. To explore the therapeutic potential of BAT, it is essential to determine whether pharmacological agents can activate BAT.


METHODS
We aimed to determine whether BAT can be activated in lean and obese humans after acute administration of an orally bioavailable sympathomimetic. In a randomised, double-blinded, crossover trial, we administered 2.5 mg/kg of oral ephedrine to nine lean (BMI 22 ± 1 kg/m²) and nine obese (BMI 36 ± 1 kg/m²) young men. On a separate day, a placebo was administered to the same participants. BAT activity was assessed by measuring glucose uptake with [¹⁸F]fluorodeoxyglucose and positron emission tomography-computed tomography imaging.


RESULTS
BAT activity was increased by ephedrine compared with placebo in the lean, but unchanged in the obese, participants. The change in BAT activity after ephedrine compared with placebo was negatively correlated with various indices of body fatness.


CONCLUSIONS
BAT can be activated via acute, oral administration of the sympathomimetic ephedrine in lean, but not in obese humans.
Metabolic and Vascular Physiology Laboratory, Baker IDI Heart and Diabetes Institute, PO Box 6492, St Kilda Road Central, Melbourne, VIC 8008, Australia. andrew.carey@bakeridi.edu.au
A L
AL
Carey
M F
MF
Formosa
B
B
Van Every
D
D
Bertovic
N
N
Eikelis
G W
GW
Lambert
V
V
Kalff
S J
SJ
Duffy
M H
MH
Cherk
B A
BA
Kingwell
D002001:Adipose Tissue, Brown / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D018663:Adrenergic Agents / Q000494:pharmacology*; D000328:Adult; D001692:Biological Transport / Q000187:drug effects; D015992:Body Mass Index; D002153:Calorimetry, Indirect; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004809:Ephedrine / Q000494:pharmacology*; D019788:Fluorodeoxyglucose F18 / Q000032:analysis; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008297:Male; D064847:Multimodal Imaging; D009765:Obesity / Q000378:metabolism*; D049268:Positron-Emission Tomography; D013566:Sympathomimetics / Q000494:pharmacology*; D022722:Thermogenesis / Q000187:drug effects*; D013851:Thinness / Q000378:metabolism*; D014057:Tomography, X-Ray Computed; D055815:Young Adult
D018663:Adrenergic Agents; D013566:Sympathomimetics; D019788:Fluorodeoxyglucose F18; D004809:Ephedrine; D005947:Glucose