Regulation and expression of a renin-angiotensin system in human pancreas and pancreatic endocrine tumours.

OBJECTIVE Evidence exists for the presence of a renin-angiotensin system (RAS) in the pancreas. The aims of this study were to prove the presence of an intrinsic RAS in the human pancreas and to analyse the role of such an RAS in pancreatic endocrine tumours (PETs). METHODS Gene expression of key RAS components (angiotensinogen and angiotensin II receptors, namely AT1 and AT2) was investigated in human pancreas and in PETs by semi-quantitative RT-PCR and immunohistochemistry. RESULTS Expression of mRNAs of RAS components was found in human pancreas and in PETs. Data from semi-quantitative RT-PCR analysis demonstrated an increase in the mRNA expression of angiotensinogen and AT2 receptor in PETs when compared with that in normal pancreas. By immunohistochemistry, angiotensinogen protein was predominantly localized in the pancreatic islets while AT1 receptor protein was in the pancreatic ducts. CONCLUSIONS The data support the notion of the existence of an intrinsic RAS in the human pancreas. It also indicates, for the first time, that such a local pancreatic RAS is subject to regulation by PETs and its significant change may have pathophysiological relevance in patients with PETs.