Ip Siu Po, Chan Yik Wai, Leung Po Sing
Department of Physiology and School of Chinese Medicine, The Chinese University of Hong Kong, Hong Kong.
Pancreas. 2002 Oct;25(3):296-300. doi: 10.1097/00006676-200210000-00013.
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.
Adult Sprague-Dawley rats were exposed to isobaric hypoxia (10% O2), and the effects on the circulating and pancreatic RAS were documented.
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.
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.
循环肾素-血管紧张素系统（RAS）在血压、电解质及液体平衡的调节中起关键作用。与循环RAS不同，不同组织/器官中已证实存在内在RAS，其可能影响生物系统的局部和整体功能。我们之前的研究为大鼠胰腺中存在局部RAS提供了确凿证据。我们进一步的研究表明，这种胰腺RAS可被慢性缺氧实验模型和化学诱导的胰腺炎激活。这些先前的发现构成了本研究的基础。
将成年Sprague-Dawley大鼠暴露于等压缺氧环境（10%氧气），并记录其对循环和胰腺RAS的影响。
本研究表明，将大鼠暴露于等压缺氧环境会导致血浆肾素活性随时间增加。缺氧对循环RAS的激活与局部RAS成分的平行上调相关，包括胰腺中血管紧张素原以及血管紧张素II 1型和2型受体的mRNA表达。
局部胰腺RAS及其对应的循环RAS的上调，可能是慢性缺氧应激下生物系统生理和病理生理方面的原因。
