Objective: 

In this study it was 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, five days per week for 28 days at level grade in exercise groups. DHA was given HD and HED groups every day orally (36 mg/kg). The animals except controls were exposured to hypoxia during twenty-eight days.

Results: 

Serum levels of GH and IGF-I in H group decreased after chronic hypoxia (p<0.001). GH and IGF-I in HD group also decreased compared with C group (p<0.05, p<0.01, respectively). GH in controls did not show significant difference compared with HE and HED groups. Decreased serum level of IGF-I was observed for HED group (p<0.05).

Conclusions: 

According to findings, we can say that chronic hypoxia exposure decreases serum levels of GH and IGF-I and exercise training have slightly positive effect on GH/IGF-I axis during hypoxia. Also DHA supplementation slightly increases GH and IGF-I serum levels in hypoxic conditions. But this effect on GH/IGF-I axis during hypoxia is not strong compared with exercise. That's why we concluded that exercise and/or DHA supplementation doesn't have additional positive effect on these hormones in hypoxic conditions.

This study was supported by Pamukkale University Research Fund.