title: Endurance exercise is a leptin signaling mimetic in hypothalamus of Wistar rats.
abstract: BACKGROUND
  Endurance exercise is known to promote a substantial effect on the energy balance in rats and humans. However, little is known about the exact mechanisms for the appetite-suppressive effects of endurance exercise. We hypothesized that endurance training might activate signaling cascades in the hypothalamus known to be involved in leptin signaling.
  
  
  METHODS
  16 male Wistar rats were randomly assigned to two groups: sedentary (n = 8) and exercise groups (n = 8). Animals in the exercise group started treadmill running at 30 m/min, 0% grade, for 1 min/bout. Running time was gradually increased by 2 min/bout every day. The training plan was one bout per day during initial two weeks, and two bouts per day during 3rd-9th week. At the end of nine-week experiment, blood was analyzed for low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), total cholesterol (TC), free fatty acid (FFA), interleukin (IL)-6, and leptin in both groups. Activations of janus kinase 2-signaling transducer and activator of transcription 3 (JAK2-STAT3), protein kinase B (Akt), extracellular regulated kninase (ERKs), and suppressor of cytokine signaling 3 (SOCS3) in hypothalamus were measured in the end of nine weeks of exercise protocol.
  
  
  RESULTS
  Nine-week endurance exercise induced lower concentrations of LDL-C, TG, TC, FFA, and leptin in rats (P < 0.05 or P < 0.01). Nine-week endurance exercise significantly increased the circulating IL-6 concentration compared with sedentary group (239.6 ± 37.2 pg/ml vs. 151.8 ± 31.5 pg/ml, P < 0.01). Exercise rats showed significant increases in JAK2, STAT3, Akt, ERKs, and SOCS3 phosphorylations compared with sedentary rats (P < 0.01).
  
  
  CONCLUSIONS
  The data suggest that endurance exercise is a leptin signaling mimetic in hypothalamus of Wistar rats.
authors.affiliation: Sport Biological Center, China Institute of Sport Science, Beijing 100061, PR China.
authors.forename: Jiexiu
authors.initials: J
authors.lastname: Zhao
authors.forename: Ye
authors.initials: Y
authors.lastname: Tian
authors.forename: Jincheng
authors.initials: J
authors.lastname: Xu
authors.forename: Dongsen
authors.initials: D
authors.lastname: Liu
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Wang
authors.forename: Binxiu
authors.initials: B
authors.lastname: Zhao
mesh_terms: D000818:Animals; D008078:Cholesterol, LDL / Q000097:blood; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D007031:Hypothalamus / Q000201:enzymology / Q000502:physiology*; D053614:Janus Kinase 2 / Q000378:metabolism; D020738:Leptin / Q000097:blood*; D050356:Lipid Metabolism; D008297:Male; D010766:Phosphorylation; D010805:Physical Conditioning, Animal; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000378:metabolism; D014280:Triglycerides / Q000097:blood
chemical_list: D008078:Cholesterol, LDL; D005230:Fatty Acids, Nonesterified; D020738:Leptin; D050796:STAT3 Transcription Factor; C491410:Socs3 protein, rat; C494088:Stat3 protein, rat; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D014280:Triglycerides; C507927:Jak2 protein, rat; D053614:Janus Kinase 2; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases