title: Are blood flow and lipolysis in subcutaneous adipose tissue influenced by contractions in adjacent muscles in humans?
abstract: Aerobic exercise increases whole body adipose tissue lipolysis, but is lipolysis higher in subcutaneous adipose tissue (SCAT) adjacent to contracting muscles than in SCAT adjacent to resting muscles? Ten healthy, overnight-fasted males performed one-legged knee extension exercise at 25% of maximal workload (W(max)) for 30 min followed by exercise at 55% W(max) for 120 min with the other leg and finally exercised at 85% W(max) for 30 min with the first leg. Subjects rested for 30 min between exercise periods. Femoral SCAT blood flow was estimated from washout of (133)Xe, and lipolysis was calculated from femoral SCAT interstitial and arterial glycerol concentrations and blood flow. In general, blood flow and lipolysis were higher in femoral SCAT adjacent to contracting than adjacent to resting muscle (time 15-30 min; blood flow: 25% W(max) 6.6 +/- 1.0 vs. 3.9 +/- 0.8 ml x 100 g(-1) x min(-1), P < 0.05; 55% W(max) 7.3 +/- 0.6 vs. 5.0 +/- 0.6 ml x 100 g(-1) x min(-1), P < 0.05; 85% W(max) 6.6 +/- 1.3 vs. 5.9 +/- 0.7 ml x 100 g(-1) x min(-1), P > 0.05; lipolysis: 25% W(max) 102 +/- 19 vs. 55 +/- 14 nmol x 100 g(-1) x min(-1), P = 0.06; 55% W(max) 86 +/- 11 vs. 50 +/- 20 nmol x 100 g(-1) x min(-1), P > 0.05; 85% W(max) 88 +/- 31 vs. -9 +/- 25 nmol x 100 g(-1) x min(-1), P < 0.05). In conclusion, blood flow and lipolysis are generally higher in SCAT adjacent to contracting than adjacent to resting muscle irrespective of exercise intensity. Thus specific exercises can induce "spot lipolysis" in adipose tissue.
authors.affiliation: Department of Medical Physiology, The Panum Institute, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark. B.Stallknecht@mfi.ku.dk
authors.forename: Bente
authors.initials: B
authors.lastname: Stallknecht
authors.forename: Flemming
authors.initials: F
authors.lastname: Dela
authors.forename: Jørn Wulff
authors.initials: JW
authors.lastname: Helge
mesh_terms: D000328:Adult; D004837:Epinephrine / Q000097:blood; D015444:Exercise; D005263:Femoral Artery / Q000737:chemistry; D005990:Glycerol / Q000032:analysis / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D008066:Lipolysis; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology; D012039:Regional Blood Flow; D050151:Subcutaneous Fat / Q000098:blood supply* / Q000737:chemistry / Q000378:metabolism*
chemical_list: D007328:Insulin; D005990:Glycerol; D004837:Epinephrine