title: Metabolic activity of brown, "beige," and white adipose tissues in response to chronic adrenergic stimulation in male mice.
abstract: Classical brown adipocytes such as those found in interscapular brown adipose tissue (iBAT) represent energy-burning cells, which have been postulated to play a pivotal role in energy metabolism. Brown adipocytes can also be found in white adipose tissue (WAT) depots [e.g., inguinal WAT (iWAT)] following adrenergic stimulation, and they have been referred to as "beige" adipocytes. Whether the presence of these adipocytes, which gives iWAT a beige appearance, can confer a white depot with some thermogenic activity remains to be seen. In consequence, we designed the present study to investigate the metabolic activity of iBAT, iWAT, and epididymal white depots in mice. Mice were either 1) kept at thermoneutrality (30°C), 2) kept at 30°C and treated daily for 14 days with an adrenergic agonist [CL-316,243 (CL)], or 3) housed at 10°C for 14 days. Metabolic activity was assessed using positron emission tomography imaging with fluoro-[(18)F]deoxyglucose (glucose uptake), fluoro-[(18)F]thiaheptadecanoic acid (fatty acid uptake), and [(11)C]acetate (oxidative activity). In each group, substrate uptakes and oxidative activity were measured in anesthetized mice in response to acute CL. Our results revealed iBAT as a major site of metabolic activity, which exhibited enhanced glucose and nonesterified fatty acid uptakes and oxidative activity in response to chronic cold and CL. On the other hand, beige adipose tissue failed to exhibit appreciable increase in oxidative activity in response to chronic cold and CL. Altogether, our results suggest that the contribution of beige fat to acute-CL-induced metabolic activity is low compared with that of iBAT, even after sustained adrenergic stimulation.
authors.affiliation: Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, Canada; and.
authors.forename: Sébastien M
authors.initials: SM
authors.lastname: Labbé
authors.affiliation: Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, Canada; and.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Caron
authors.affiliation: Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, Canada; and.
authors.forename: Kanta
authors.initials: K
authors.lastname: Chechi
authors.affiliation: Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, Canada; and.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Laplante
authors.affiliation: Departments of Nuclear Medicine and Radiobiology, Centre d'imagerie moléculaire de Sherbrooke, Université de Sherbrooke, Sherbrooke, Canada.
authors.forename: Roger
authors.initials: R
authors.lastname: Lecomte
authors.affiliation: Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, Canada; and denis.richard@criucpq.ulaval.ca.
authors.forename: Denis
authors.initials: D
authors.lastname: Richard
mesh_terms: D000085:Acetates; D000069796:Adipose Tissue, Beige / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D002001:Adipose Tissue, Brown / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D052436:Adipose Tissue, White / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D058667:Adrenergic beta-3 Receptor Agonists / Q000494:pharmacology*; D000818:Animals; D002250:Carbon Radioisotopes; D003080:Cold Temperature; D004149:Dioxoles / Q000494:pharmacology*; D005227:Fatty Acids; D019788:Fluorodeoxyglucose F18; D008297:Male; D051379:Mice; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals
chemical_list: D000085:Acetates; D058667:Adrenergic beta-3 Receptor Agonists; D002250:Carbon Radioisotopes; D004149:Dioxoles; D005227:Fatty Acids; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; C076126:disodium (R,R)-5-(2-((2-(3-chlorophenyl)-2-hydroxyethyl)-amino)propyl)-1,3-benzodioxole-2,3-dicarboxylate; C013102:margaric acid
keywords: beige adipose tissue; brown adipose tissue; energy metabolism; oxidative metabolism; positron emission tomography