title: Liver and Muscle Contribute Differently to the Plasma Acylcarnitine Pool During Fasting and Exercise in Humans.
abstract: Plasma acylcarnitine levels are elevated by physiological conditions such as fasting and exercise but also in states of insulin resistance and obesity.
  
  
  
  To elucidate the contribution of liver and skeletal muscle to plasma acylcarnitines in the fasting state and during exercise in humans.
  
  
  
  In 2 independent studies, young healthy males were fasted overnight and performed an acute bout of exercise to investigate either acylcarnitines in skeletal muscle biopsies and arterial-to-venous plasma differences over the exercising and resting leg (n = 9) or the flux over the hepato-splanchnic bed (n = 10).
  
  
  
  In the fasting state, a pronounced release of C2- and C3-carnitines from the hepato-splanchnic bed and an uptake of free carnitine by the legs were detected. Exercise further increased the release of C3-carnitine from the hepato-splanchnic bed and the uptake of free carnitine in the exercising leg. In plasma and in the exercising muscle, exercise induced an increase of most acylcarnitines followed by a rapid decline to preexercise values during recovery. In contrast, free carnitine was decreased in the exercising muscle and quickly restored thereafter. C8-, C10-, C10:1-, C12-, and C12:1-carnitines were released from the exercising leg and simultaneously; C6, C8, C10, C10:1, C14, and C16:1 were taken up by the hepato-splanchnic.
  
  
  
  These data provide novel insight to the organo-specific release/uptake of acylcarnitines. The liver is a major contributor to systemic short chain acylcarnitines, whereas the muscle tissue releases mostly medium chain acylcarnitines during exercise, indicating that other tissues are contributing to the systemic increase in long chain acylcarnitines.
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry (G.X., X.J.Z., X.L.W.), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China; Department of Clinical Biochemistry (J.S.H., P.P.), Rigshospitalet, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (J.S.H., B.K.P., P.P.), Department of Infectious Diseases and CMRC, Rigshospitalet, Copenhagen, Denmark; Department of General Surgery and Laboratory of General Surgery (S.C.), Xinhua Hospital, affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Biliary Tract Diseases Research (S.C.), Shanghai Jiao Tong University School of Medicine, Shanghai, China; Division of Endocrinology (M.H., H.U.H., R.L., C.W.), Diabetology, Angiology, Nephrology, Pathobiochemistry and Clinical Chemistry, Department of Internal Medicine IV, University Tuebingen, Germany; Department of Hepatology (J.O.C.), Rigshospitalet, Copenhagen, Denmark; Department of Anaesthesiology (N.H.S.), The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tuebingen (H.U.H., R.L., C.W.), Tuebingen, Germany; and German Center for Diabetes Research (H.U.H., R.L., C.W.), Germany.
authors.forename: G
authors.initials: G
authors.lastname: Xu
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry (G.X., X.J.Z., X.L.W.), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China; Department of Clinical Biochemistry (J.S.H., P.P.), Rigshospitalet, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (J.S.H., B.K.P., P.P.), Department of Infectious Diseases and CMRC, Rigshospitalet, Copenhagen, Denmark; Department of General Surgery and Laboratory of General Surgery (S.C.), Xinhua Hospital, affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Biliary Tract Diseases Research (S.C.), Shanghai Jiao Tong University School of Medicine, Shanghai, China; Division of Endocrinology (M.H., H.U.H., R.L., C.W.), Diabetology, Angiology, Nephrology, Pathobiochemistry and Clinical Chemistry, Department of Internal Medicine IV, University Tuebingen, Germany; Department of Hepatology (J.O.C.), Rigshospitalet, Copenhagen, Denmark; Department of Anaesthesiology (N.H.S.), The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tuebingen (H.U.H., R.L., C.W.), Tuebingen, Germany; and German Center for Diabetes Research (H.U.H., R.L., C.W.), Germany.
authors.forename: J S
authors.initials: JS
authors.lastname: Hansen
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry (G.X., X.J.Z., X.L.W.), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China; Department of Clinical Biochemistry (J.S.H., P.P.), Rigshospitalet, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (J.S.H., B.K.P., P.P.), Department of Infectious Diseases and CMRC, Rigshospitalet, Copenhagen, Denmark; Department of General Surgery and Laboratory of General Surgery (S.C.), Xinhua Hospital, affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Biliary Tract Diseases Research (S.C.), Shanghai Jiao Tong University School of Medicine, Shanghai, China; Division of Endocrinology (M.H., H.U.H., R.L., C.W.), Diabetology, Angiology, Nephrology, Pathobiochemistry and Clinical Chemistry, Department of Internal Medicine IV, University Tuebingen, Germany; Department of Hepatology (J.O.C.), Rigshospitalet, Copenhagen, Denmark; Department of Anaesthesiology (N.H.S.), The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tuebingen (H.U.H., R.L., C.W.), Tuebingen, Germany; and German Center for Diabetes Research (H.U.H., R.L., C.W.), Germany.
authors.forename: X J
authors.initials: XJ
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry (G.X., X.J.Z., X.L.W.), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China; Department of Clinical Biochemistry (J.S.H., P.P.), Rigshospitalet, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (J.S.H., B.K.P., P.P.), Department of Infectious Diseases and CMRC, Rigshospitalet, Copenhagen, Denmark; Department of General Surgery and Laboratory of General Surgery (S.C.), Xinhua Hospital, affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Biliary Tract Diseases Research (S.C.), Shanghai Jiao Tong University School of Medicine, Shanghai, China; Division of Endocrinology (M.H., H.U.H., R.L., C.W.), Diabetology, Angiology, Nephrology, Pathobiochemistry and Clinical Chemistry, Department of Internal Medicine IV, University Tuebingen, Germany; Department of Hepatology (J.O.C.), Rigshospitalet, Copenhagen, Denmark; Department of Anaesthesiology (N.H.S.), The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tuebingen (H.U.H., R.L., C.W.), Tuebingen, Germany; and German Center for Diabetes Research (H.U.H., R.L., C.W.), Germany.
authors.forename: S
authors.initials: S
authors.lastname: Chen
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry (G.X., X.J.Z., X.L.W.), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China; Department of Clinical Biochemistry (J.S.H., P.P.), Rigshospitalet, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (J.S.H., B.K.P., P.P.), Department of Infectious Diseases and CMRC, Rigshospitalet, Copenhagen, Denmark; Department of General Surgery and Laboratory of General Surgery (S.C.), Xinhua Hospital, affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Biliary Tract Diseases Research (S.C.), Shanghai Jiao Tong University School of Medicine, Shanghai, China; Division of Endocrinology (M.H., H.U.H., R.L., C.W.), Diabetology, Angiology, Nephrology, Pathobiochemistry and Clinical Chemistry, Department of Internal Medicine IV, University Tuebingen, Germany; Department of Hepatology (J.O.C.), Rigshospitalet, Copenhagen, Denmark; Department of Anaesthesiology (N.H.S.), The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tuebingen (H.U.H., R.L., C.W.), Tuebingen, Germany; and German Center for Diabetes Research (H.U.H., R.L., C.W.), Germany.
authors.forename: M
authors.initials: M
authors.lastname: Hoene
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry (G.X., X.J.Z., X.L.W.), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China; Department of Clinical Biochemistry (J.S.H., P.P.), Rigshospitalet, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (J.S.H., B.K.P., P.P.), Department of Infectious Diseases and CMRC, Rigshospitalet, Copenhagen, Denmark; Department of General Surgery and Laboratory of General Surgery (S.C.), Xinhua Hospital, affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Biliary Tract Diseases Research (S.C.), Shanghai Jiao Tong University School of Medicine, Shanghai, China; Division of Endocrinology (M.H., H.U.H., R.L., C.W.), Diabetology, Angiology, Nephrology, Pathobiochemistry and Clinical Chemistry, Department of Internal Medicine IV, University Tuebingen, Germany; Department of Hepatology (J.O.C.), Rigshospitalet, Copenhagen, Denmark; Department of Anaesthesiology (N.H.S.), The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tuebingen (H.U.H., R.L., C.W.), Tuebingen, Germany; and German Center for Diabetes Research (H.U.H., R.L., C.W.), Germany.
authors.forename: X L
authors.initials: XL
authors.lastname: Wang
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry (G.X., X.J.Z., X.L.W.), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China; Department of Clinical Biochemistry (J.S.H., P.P.), Rigshospitalet, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (J.S.H., B.K.P., P.P.), Department of Infectious Diseases and CMRC, Rigshospitalet, Copenhagen, Denmark; Department of General Surgery and Laboratory of General Surgery (S.C.), Xinhua Hospital, affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Biliary Tract Diseases Research (S.C.), Shanghai Jiao Tong University School of Medicine, Shanghai, China; Division of Endocrinology (M.H., H.U.H., R.L., C.W.), Diabetology, Angiology, Nephrology, Pathobiochemistry and Clinical Chemistry, Department of Internal Medicine IV, University Tuebingen, Germany; Department of Hepatology (J.O.C.), Rigshospitalet, Copenhagen, Denmark; Department of Anaesthesiology (N.H.S.), The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tuebingen (H.U.H., R.L., C.W.), Tuebingen, Germany; and German Center for Diabetes Research (H.U.H., R.L., C.W.), Germany.
authors.forename: J O
authors.initials: JO
authors.lastname: Clemmesen
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry (G.X., X.J.Z., X.L.W.), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China; Department of Clinical Biochemistry (J.S.H., P.P.), Rigshospitalet, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (J.S.H., B.K.P., P.P.), Department of Infectious Diseases and CMRC, Rigshospitalet, Copenhagen, Denmark; Department of General Surgery and Laboratory of General Surgery (S.C.), Xinhua Hospital, affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Biliary Tract Diseases Research (S.C.), Shanghai Jiao Tong University School of Medicine, Shanghai, China; Division of Endocrinology (M.H., H.U.H., R.L., C.W.), Diabetology, Angiology, Nephrology, Pathobiochemistry and Clinical Chemistry, Department of Internal Medicine IV, University Tuebingen, Germany; Department of Hepatology (J.O.C.), Rigshospitalet, Copenhagen, Denmark; Department of Anaesthesiology (N.H.S.), The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tuebingen (H.U.H., R.L., C.W.), Tuebingen, Germany; and German Center for Diabetes Research (H.U.H., R.L., C.W.), Germany.
authors.forename: N H
authors.initials: NH
authors.lastname: Secher
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry (G.X., X.J.Z., X.L.W.), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China; Department of Clinical Biochemistry (J.S.H., P.P.), Rigshospitalet, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (J.S.H., B.K.P., P.P.), Department of Infectious Diseases and CMRC, Rigshospitalet, Copenhagen, Denmark; Department of General Surgery and Laboratory of General Surgery (S.C.), Xinhua Hospital, affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Biliary Tract Diseases Research (S.C.), Shanghai Jiao Tong University School of Medicine, Shanghai, China; Division of Endocrinology (M.H., H.U.H., R.L., C.W.), Diabetology, Angiology, Nephrology, Pathobiochemistry and Clinical Chemistry, Department of Internal Medicine IV, University Tuebingen, Germany; Department of Hepatology (J.O.C.), Rigshospitalet, Copenhagen, Denmark; Department of Anaesthesiology (N.H.S.), The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tuebingen (H.U.H., R.L., C.W.), Tuebingen, Germany; and German Center for Diabetes Research (H.U.H., R.L., C.W.), Germany.
authors.forename: H U
authors.initials: HU
authors.lastname: Häring
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry (G.X., X.J.Z., X.L.W.), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China; Department of Clinical Biochemistry (J.S.H., P.P.), Rigshospitalet, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (J.S.H., B.K.P., P.P.), Department of Infectious Diseases and CMRC, Rigshospitalet, Copenhagen, Denmark; Department of General Surgery and Laboratory of General Surgery (S.C.), Xinhua Hospital, affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Biliary Tract Diseases Research (S.C.), Shanghai Jiao Tong University School of Medicine, Shanghai, China; Division of Endocrinology (M.H., H.U.H., R.L., C.W.), Diabetology, Angiology, Nephrology, Pathobiochemistry and Clinical Chemistry, Department of Internal Medicine IV, University Tuebingen, Germany; Department of Hepatology (J.O.C.), Rigshospitalet, Copenhagen, Denmark; Department of Anaesthesiology (N.H.S.), The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tuebingen (H.U.H., R.L., C.W.), Tuebingen, Germany; and German Center for Diabetes Research (H.U.H., R.L., C.W.), Germany.
authors.forename: B K
authors.initials: BK
authors.lastname: Pedersen
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry (G.X., X.J.Z., X.L.W.), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China; Department of Clinical Biochemistry (J.S.H., P.P.), Rigshospitalet, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (J.S.H., B.K.P., P.P.), Department of Infectious Diseases and CMRC, Rigshospitalet, Copenhagen, Denmark; Department of General Surgery and Laboratory of General Surgery (S.C.), Xinhua Hospital, affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Biliary Tract Diseases Research (S.C.), Shanghai Jiao Tong University School of Medicine, Shanghai, China; Division of Endocrinology (M.H., H.U.H., R.L., C.W.), Diabetology, Angiology, Nephrology, Pathobiochemistry and Clinical Chemistry, Department of Internal Medicine IV, University Tuebingen, Germany; Department of Hepatology (J.O.C.), Rigshospitalet, Copenhagen, Denmark; Department of Anaesthesiology (N.H.S.), The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tuebingen (H.U.H., R.L., C.W.), Tuebingen, Germany; and German Center for Diabetes Research (H.U.H., R.L., C.W.), Germany.
authors.forename: R
authors.initials: R
authors.lastname: Lehmann
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry (G.X., X.J.Z., X.L.W.), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China; Department of Clinical Biochemistry (J.S.H., P.P.), Rigshospitalet, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (J.S.H., B.K.P., P.P.), Department of Infectious Diseases and CMRC, Rigshospitalet, Copenhagen, Denmark; Department of General Surgery and Laboratory of General Surgery (S.C.), Xinhua Hospital, affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Biliary Tract Diseases Research (S.C.), Shanghai Jiao Tong University School of Medicine, Shanghai, China; Division of Endocrinology (M.H., H.U.H., R.L., C.W.), Diabetology, Angiology, Nephrology, Pathobiochemistry and Clinical Chemistry, Department of Internal Medicine IV, University Tuebingen, Germany; Department of Hepatology (J.O.C.), Rigshospitalet, Copenhagen, Denmark; Department of Anaesthesiology (N.H.S.), The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tuebingen (H.U.H., R.L., C.W.), Tuebingen, Germany; and German Center for Diabetes Research (H.U.H., R.L., C.W.), Germany.
authors.forename: Cora
authors.initials: C
authors.lastname: Weigert
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry (G.X., X.J.Z., X.L.W.), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China; Department of Clinical Biochemistry (J.S.H., P.P.), Rigshospitalet, Copenhagen, Denmark; The Centre of Inflammation and Metabolism and the Centre for Physical Activity Research (J.S.H., B.K.P., P.P.), Department of Infectious Diseases and CMRC, Rigshospitalet, Copenhagen, Denmark; Department of General Surgery and Laboratory of General Surgery (S.C.), Xinhua Hospital, affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China; Institute of Biliary Tract Diseases Research (S.C.), Shanghai Jiao Tong University School of Medicine, Shanghai, China; Division of Endocrinology (M.H., H.U.H., R.L., C.W.), Diabetology, Angiology, Nephrology, Pathobiochemistry and Clinical Chemistry, Department of Internal Medicine IV, University Tuebingen, Germany; Department of Hepatology (J.O.C.), Rigshospitalet, Copenhagen, Denmark; Department of Anaesthesiology (N.H.S.), The Copenhagen Muscle Research Centre, Rigshospitalet, Copenhagen, Denmark; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Zentrum München at the University of Tuebingen (H.U.H., R.L., C.W.), Tuebingen, Germany; and German Center for Diabetes Research (H.U.H., R.L., C.W.), Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Plomgaard
mesh_terms: D000328:Adult; D002331:Carnitine / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D005215:Fasting / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007866:Leg; D008099:Liver / Q000378:metabolism*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D055815:Young Adult
chemical_list: C116917:acylcarnitine; D002331:Carnitine