title: Different metabolic responses of human brown adipose tissue to activation by cold and insulin.
abstract: We investigated the metabolism of human brown adipose tissue (BAT) in healthy subjects by determining its cold-induced and insulin-stimulated glucose uptake and blood flow (perfusion) using positron emission tomography (PET) combined with computed tomography (CT). Second, we assessed gene expression in human BAT and white adipose tissue (WAT). Glucose uptake was induced 12-fold in BAT by cold, accompanied by doubling of perfusion. We found a positive association between whole-body energy expenditure and BAT perfusion. Insulin enhanced glucose uptake 5-fold in BAT independently of its perfusion, while the effect on WAT was weaker. The gene expression level of insulin-sensitive glucose transporter GLUT4 was also higher in BAT as compared to WAT. In conclusion, BAT appears to be differently activated by insulin and cold; in response to insulin, BAT displays high glucose uptake without increased perfusion, but when activated by cold, it dissipates energy in a perfusion-dependent manner.
authors.affiliation: Turku PET Centre, University of Turku, Turku, Finland.
authors.forename: Janne
authors.initials: J
authors.lastname: Orava
authors.forename: Pirjo
authors.initials: P
authors.lastname: Nuutila
authors.forename: Martin E
authors.initials: ME
authors.lastname: Lidell
authors.forename: Vesa
authors.initials: V
authors.lastname: Oikonen
authors.forename: Tommi
authors.initials: T
authors.lastname: Noponen
authors.forename: Tapio
authors.initials: T
authors.lastname: Viljanen
authors.forename: Mika
authors.initials: M
authors.lastname: Scheinin
authors.forename: Markku
authors.initials: M
authors.lastname: Taittonen
authors.forename: Tarja
authors.initials: T
authors.lastname: Niemi
authors.forename: Sven
authors.initials: S
authors.lastname: Enerbäck
authors.forename: Kirsi A
authors.initials: KA
authors.lastname: Virtanen
mesh_terms: D002001:Adipose Tissue, Brown / Q000378:metabolism*; D052436:Adipose Tissue, White / Q000378:metabolism; D000328:Adult; D001783:Blood Flow Velocity; D002478:Cells, Cultured; D003080:Cold Temperature; D004734:Energy Metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism; D051275:Glucose Transporter Type 4 / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography
chemical_list: D051275:Glucose Transporter Type 4; D007328:Insulin; C495692:SLC2A4 protein, human; D005947:Glucose