The Effect of High Altitude on Blood Hormones in Male Westar Rats in South Western Saudi Arabia

Problem statement: Living in high altitude areas results in chronic hypoxia, which induces complex metabolic and endocrine adaptations. The current study investigated the endocrine responses of male Westar rats chronically exposed to high altitude-induced hypoxia in Abha City, in Southwestern Saudi Arabia. Approach: The rats were separated in to 2 groups of 10 rats. The first group was kept at an altitude of 600 m above sea level in the King Saud University animal house in Riyadh City and designated the low altitude group; the second group of rats was transferred to the King Khalid University animal house in Abha City, which is 2800 m height above sea level and was designated the high altitude group. All rats were housed under the same laboratory conditions and fed the same diet. Blood samples were collected from both groups of animals 45 days after transferring the high altitude group to Abha City. Results: The data revealed that the rats transferred to the high altitude area had significant decreases in serum Thyroid Stimulating Hormone (TSH) and testosterone levels and significant increases in the levels of serum cortisol, free Triiodothyronine (T3) and free Thyroxin (T4) compared to rats kept at low altitude. Conclusion: The current study demonstrates that rats chronically exposed to high altitude hypoxia experienced alternations in various hormones. These findings will contribute to a better understanding of human endocrine and metabolic physiology in hypoxic conditions. Key word: High altitude, hormones, TSH, testosterone, Saudi Arabia