title: Chronic exposure of rats to native high altitude increases in blood pressure via activation of the renin-angiotensin-aldosterone system.
abstract: OBJECTIVE
  To study the effect of chronic exposure to native high altitude (HA) on blood pressure, and to investigate the underlying mechanism of action.
  
  
  METHODS
  This study was carried out between February and April 2011. A total of 20 male rats were divided   into 2 groups (n=10 rats). The low altitude (LA) group were rats born and lived in an LA environment at King Saud University, College of Pharmacy, Riyadh, Kingdom of Saudi Arabia (KSA), and the HA group were rats born in the same LA area, then acclimatized to HA area in Physiology Department, King Khalid University, College of Medicine, Abha, KSA for 90 days. At the end of day 90, hematocrit, plasma renin activity, aldosterone, norepinephrine and vasopressin levels were determined in both groups. Invasive arterial blood pressure was also measured, and fractional excretion of sodium (FENa), and potassium (FEK) were calculated. The quantitative real time-polymerase chain reaction of renin was carried out in the kidneys of both rat groups.
  
  
  RESULTS
  When compared to LA native rats, HA rats exhibited a significant increase in systolic and diastolic blood pressure with a significant increase in renin plasma activity as well as an increase in the levels of aldosterone, norepinephrine, and vasopressin. Furthermore, HA rats showed a significant increase in renin expression in their kidneys, as well as decreased FENa.
  
  
  CONCLUSIONS
  Data shows that prolonged exposure to HA results in elevated blood pressure precipitated by the activation of the renin-angiotensin-aldosterone system.
authors.affiliation: Department of Physiology, College of Medicine, King Khalid University, Abha 61421, Kingdom of Saudi Arabia fahaid999@yahoo.com
authors.forename: Fahaid H
authors.initials: FH
authors.lastname: Al-Hashem
authors.forename: Mahmoud A
authors.initials: MA
authors.lastname: Alkhateeb
authors.forename: Abdullah S
authors.initials: AS
authors.lastname: Shatoor
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Khalil
authors.forename: Hussein F
authors.initials: HF
authors.lastname: Sakr
mesh_terms: D000450:Aldosterone / Q000097:blood; D000531:Altitude; D000818:Animals; D001794:Blood Pressure; D008297:Male; D009638:Norepinephrine / Q000097:blood; D051381:Rats; D017208:Rats, Wistar; D012083:Renin / Q000378:metabolism; D012084:Renin-Angiotensin System; D012964:Sodium / Q000652:urine; D014667:Vasopressins / Q000097:blood
chemical_list: D014667:Vasopressins; D000450:Aldosterone; D012964:Sodium; D012083:Renin; D009638:Norepinephrine