title: Short-,moderate-, and long-term treadmill training protocols reduce plasma, fundus, but not small intestine ghrelin concentrations in male rats.
abstract: BACKGROUND
  It has been suggested that circulating ghrelin levels are upregulated by fasting, hypoglycemic status, and a physical exercise-induced energy deficit.
  
  
  OBJECTIVE
  The purpose of the present study was to investigate the timecourse adaptations of the plasma, fundus, and small intestine ghrelin concentrations as well as related hormones and liver ATP levels to 3, 6, and 12 weeks of treadmill endurance running.
  
  
  METHODS
  Thirty-nine male Wistar rats (12-14 weeks old) were randomly assigned to 3 control (C3, no.=5; C6, no.=7 and C12, no.=7) and 3 training groups (E3, no.=6; E6, no.=7 and E12, no.=7). The rats in the 3 training groups were exercised on a motor-driven treadmill at 25 m/min (0% grade) for 60 min/day, 5 days/week for 3, 6, and 12 weeks, respectively. The animals were sacrificed 48 h after the last session of each training program and tissues were analyzed.
  
  
  RESULTS
  Total ghrelin concentrations were significantly (p<0.05) lower in trained rat plasma and fundus tissue after all treadmill endurance running programs. Small intestine ghrelin concentrations remained unchanged. Plasma GH concentrations and liver ATP content were significantly higher in E6 and E12 groups.
  
  
  CONCLUSIONS
  Data indicate that as little as 3 weeks of moderate treadmill exercise reduces plasma and fundus total ghrelin concentrations with elevated plasma GH and liver ATP content occurring after 6 and 12 weeks of training. Exercise training-induced improvement of energy source availability and negative feedback from increased GH levels may play a role in reducing plasma and fundus ghrelin levels.
authors.affiliation: Exercise Biochemistry Division, Faculty of Physical Education & Sports Sciences, Mazandran University, Babolsar Mazandran, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Ghanbari-Niaki
authors.forename: A
authors.initials: A
authors.lastname: Jafari
authors.forename: M
authors.initials: M
authors.lastname: Moradi
authors.forename: R R
authors.initials: RR
authors.lastname: Kraemer
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D005080:Exercise Test / Q000379:methods*; D005748:Gastric Fundus / Q000378:metabolism*; D054439:Ghrelin / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism; D007421:Intestine, Small / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D010805:Physical Conditioning, Animal; D010949:Plasma / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D054439:Ghrelin; D007328:Insulin; D000255:Adenosine Triphosphate