title: Hepatic glucagon action is essential for exercise-induced reversal of mouse fatty liver.
abstract: OBJECTIVE
  Exercise is an effective intervention to treat fatty liver. However, the mechanism(s) that underlie exercise-induced reductions in fatty liver are unclear. Here we tested the hypothesis that exercise requires hepatic glucagon action to reduce fatty liver.
  
  
  METHODS
  C57BL/6 mice were fed high-fat diet (HFD) and assessed using magnetic resonance, biochemical, and histological techniques to establish a timeline for fatty liver development over 20 weeks. Glucagon receptor null (gcgr(-/-)) and wild-type (gcgr(+/+)) littermate mice were subsequently fed HFD to provoke moderate fatty liver and then performed either 10 or 6 weeks of running wheel or treadmill exercise, respectively.
  
  
  RESULTS
  Exercise reverses progression of HFD-induced fatty liver in gcgr(+/+) mice. Remarkably, such changes are absent in gcgr(-/-) mice, thus confirming the hypothesis that exercise-stimulated hepatic glucagon receptor activation is critical to reduce HFD-induced fatty liver.
  
  
  CONCLUSIONS
  These findings suggest that therapies that use antagonism of hepatic glucagon action to reduce blood glucose may interfere with the ability of exercise and perhaps other interventions to positively affect fatty liver.
authors: Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA. berglunde@gmail.com
authors: Eric D
authors: ED
authors: Berglund
authors: Daniel G
authors: DG
authors: Lustig
authors: Richard A
authors: RA
authors: Baheza
authors: Clinton M
authors: CM
authors: Hasenour
authors: Robert S
authors: RS
authors: Lee-Young
authors: E Patrick
authors: EP
authors: Donahue
authors: Sara E
authors: SE
authors: Lynes
authors: Larry L
authors: LL
authors: Swift
authors: Maureen J
authors: MJ
authors: Charron
authors: Bruce M
authors: BM
authors: Damon
authors: David H
authors: DH
authors: Wasserman
mesh_terms: D000818:Animals; D001835:Body Weight; D004041:Dietary Fats / Q000009:adverse effects; D018450:Disease Progression; D005234:Fatty Liver / Q000378:metabolism* / Q000473:pathology / Q000628:therapy*; D005934:Glucagon / Q000378:metabolism*; D050356:Lipid Metabolism; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009043:Motor Activity; D018027:Receptors, Glucagon / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D004041:Dietary Fats; D018027:Receptors, Glucagon; D005934:Glucagon