title: Brown adipose tissue takes up plasma triglycerides mostly after lipolysis.
abstract: Brown adipose tissue (BAT) produces heat by burning TGs that are stored within intracellular lipid droplets and need to be replenished by the uptake of TG-derived FA from plasma. It is currently unclear whether BAT takes up FA via uptake of TG-rich lipoproteins (TRLs), after lipolysis-mediated liberation of FA, or via a combination of both. Therefore, we generated glycerol tri[(3)H]oleate and [(14)C]cholesteryl oleate double-labeled TRL-mimicking particles with an average diameter of 45, 80, and 150 nm (representing small VLDL to chylomicrons) and injected these intravenously into male C57Bl/6J mice. At room temperature (21°C), the uptake of (3)H-activity by BAT, expressed per gram of tissue, was much higher than the uptake of (14)C-activity, irrespective of particle size, indicating lipolysis-mediated uptake of TG-derived FA rather than whole particle uptake. Cold exposure (7°C) increased the uptake of FA derived from the differently sized particles by BAT, while retaining the selectivity for uptake of FA over cholesteryl ester (CE). At thermoneutrality (28°C), total FA uptake by BAT was attenuated, but the specificity of uptake of FA over CE was again largely retained. Altogether, we conclude that, in our model, BAT takes up plasma TG preferentially by means of lipolysis-mediated uptake of FA.
authors.affiliation: Department of Endocrinology, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands Department of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: P Padmini S J
authors.initials: PP
authors.lastname: Khedoe
authors.affiliation: Department of Endocrinology, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Geerte
authors.initials: G
authors.lastname: Hoeke
authors.affiliation: Department of Endocrinology, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Sander
authors.initials: S
authors.lastname: Kooijman
authors.affiliation: Wageningen University, Wageningen, The Netherlands.
authors.forename: Wieneke
authors.initials: W
authors.lastname: Dijk
authors.affiliation: Department of Urology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Jeroen T
authors.initials: JT
authors.lastname: Buijs
authors.affiliation: Wageningen University, Wageningen, The Netherlands.
authors.forename: Sander
authors.initials: S
authors.lastname: Kersten
authors.affiliation: Department of Endocrinology, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Louis M
authors.initials: LM
authors.lastname: Havekes
authors.affiliation: Department of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Pieter S
authors.initials: PS
authors.lastname: Hiemstra
authors.affiliation: Department of Endocrinology, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Jimmy F P
authors.initials: JF
authors.lastname: Berbée
authors.affiliation: Department of Endocrinology, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Mariëtte R
authors.initials: MR
authors.lastname: Boon
authors.affiliation: Department of Endocrinology, Leiden University Medical Center, Leiden, The Netherlands Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Patrick C N
authors.initials: PC
authors.lastname: Rensen
mesh_terms: D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D002788:Cholesterol Esters / Q000378:metabolism; D008066:Lipolysis; D008074:Lipoproteins / Q000737:chemistry / Q000378:metabolism; D008297:Male; D051379:Mice; D010316:Particle Size; D013696:Temperature; D014280:Triglycerides / Q000097:blood* / Q000378:metabolism*; D014304:Triolein / Q000378:metabolism
chemical_list: D002788:Cholesterol Esters; D008074:Lipoproteins; D014280:Triglycerides; D014304:Triolein; C014409:cholesteryl oleate
keywords: cholesterol; chylomicrons; fatty acid metabolism; lipids; lipoprotein lipase; lipoproteins/metabolism