title: Effects of chronic hypoxia on the circulating and pancreatic renin-angiotensin system.
abstract: BACKGROUND
  The circulating renin-angiotensin system (RAS) plays a crucial role in the regulation of blood pressure, electrolytes, and fluid homeostasis. In contrast to the circulating RAS, the presence of an intrinsic RAS has been demonstrated in different tissues/organs, which may affect both local and global functions of a biologic system. Our previous studies provided solid evidence of the existence of a local RAS in rat pancreas. Our further investigation showed that such a pancreatic RAS could be activated by experimental models of chronic hypoxia and chemically induced pancreatitis. These previous findings formed the basis for the current study.
  
  
  METHODS
  Adult Sprague-Dawley rats were exposed to isobaric hypoxia (10% O2), and the effects on the circulating and pancreatic RAS were documented.
  
  
  RESULTS
  The current study shows that exposure of rats to isobaric hypoxia caused a time-dependent increase in plasma renin activity. The activation of circulating RAS by hypoxia was associated with a parallel upregulation of local RAS components, including the mRNA expression of angiotensinogen and angiotensin II receptor types I and II in the pancreas.
  
  
  CONCLUSIONS
  The upregulation of local pancreatic RAS, along with its counterpart circulating RAS, may be responsible for both physiologic and pathophysiologic aspects of a biologic system under chronic hypoxic stress.
authors.affiliation: Department of Physiology and School of Chinese Medicine, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Siu Po
authors.initials: SP
authors.lastname: Ip
authors.forename: Yik Wai
authors.initials: YW
authors.lastname: Chan
authors.forename: Po Sing
authors.initials: PS
authors.lastname: Leung
mesh_terms: D000808:Angiotensinogen / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D002908:Chronic Disease; D000860:Hypoxia / Q000097:blood* / Q000378:metabolism*; D007700:Kinetics; D010179:Pancreas / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D011945:Receptors, Angiotensin / Q000096:biosynthesis / Q000235:genetics; D012083:Renin / Q000097:blood; D012084:Renin-Angiotensin System; D015854:Up-Regulation
chemical_list: D012333:RNA, Messenger; D011945:Receptors, Angiotensin; D000808:Angiotensinogen; D012083:Renin