title: The effects of docosahexaenoic acid supplementation and exercise on growth hormone and insulin-like growth factor I serum levels during chronic hypoxia in rats.
abstract: BACKGROUND
  In this study we examined the effects of docosahexaenoic acid (DHA) on growth hormone (GH), insulin-like growth factor I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) in response to chronic hypoxia and exercise training in hypoxic conditions.
  
  
  METHODS
  Thirty-five rats were divided into five groups; control group (C), hypoxia group (H), hypoxia-exercise group (HE), hypoxia-docosahexaenoic acid group (HD), hypoxia-exercise-docosahexaenoic acid group (HED). A treadmill exercise was performed as 30 m/min for 20 min/day, 5 days per week for 28 days at level grade for the exercising groups (HE and HED). DHA was given to the HD and HED groups every day orally (36 mg/kg). The animals, except for the C group, were exposed to hypoxia for 28 days.
  
  
  RESULTS
  Serum levels of GH and IGF-I in the H group decreased after chronic hypoxia (p<0.001). GH and IGF-I in the HD group also decreased compared with the C group (p<0.05, p<0.01, respectively). GH in C group did not show significant difference compared with the HE and HED groups. Decreased serum level of IGF-I was observed for the HED group (p<0.05).
  
  
  CONCLUSIONS
  According to our findings, chronic hypoxia exposure decreases serum levels of GH, and IGF-I and exercise training have a slightly positive effect on GH/IGF-I axis during hypoxia. In addition, DHA supplementation slightly increases GH and IGF-I serum levels in hypoxic conditions. However, this effect on GH/IGF-I axis during hypoxia is not strong compared with exercise. Therefore, we concluded that exercise and/or DHA supplementation does not have additional positive effect on these hormones in hypoxic conditions.
authors.affiliation: Department of Physiology, University of Pamukkale, Denizli, Turkey. sturgut@pau.edu.tr
authors.forename: Sebahat
authors.initials: S
authors.lastname: Turgut
authors.forename: Haydar Ali
authors.initials: HA
authors.lastname: Erken
authors.forename: Gülten
authors.initials: G
authors.lastname: Erken
authors.forename: Ceylan
authors.initials: C
authors.lastname: Ayada
authors.forename: Osman
authors.initials: O
authors.lastname: Genc
authors.forename: Günfer
authors.initials: G
authors.lastname: Turgut
mesh_terms: D000818:Animals; D002908:Chronic Disease; D019587:Dietary Supplements; D004195:Disease Models, Animal; D004281:Docosahexaenoic Acids / Q000494:pharmacology*; D013006:Growth Hormone / Q000097:blood*; D000860:Hypoxia / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D005082:Physical Exertion; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; C548904:insulin-like growth factor-1, rat; D004281:Docosahexaenoic Acids; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone