Abstract: Objective Using the diabetic animal model, we aimed to investigate the putative role of angiotensin receptor─Mas receptor in diabetes pathogenesis. Methods Oral glucose tolerance test (OGTT) was performed in age-matched LETO and Otsuka Long-Evans Tokushima Fatty (OLETF) rats at the age of 48 weeks. The following items including blood glucose, serum insulin, serum levels of total cholesterol and triglyceride were determined in all rats. Detection of the expression of Mas and ACE2 proteins in rat pancreas using immunohistochemistry. Pancreas were procured from rats. After the digestion phrase, the islets were purified by Lymphoprep. The protein levels of Mas and ACE2 from the rats’ islets were detected by Western blotting analysis. In addition, Mas and ACE2 mRNA levels were measured by real-time PCR. Results The body weight, serum levels of total cholesterol and triglyceride, fasting blood glucose, OGTT2h blood glucose and fasting insulin levels in OLETF rats were all significantly higher than those in LETO controls (P<0.05～0.01). Mas protein and ACE2 protein were detected in both endocrine tissue and exocrine tissue of pancreas. Compared with LETO controls, the mRNA and protein levels of Mas in islets of OLETF rats showed down-regulated (P<0.05). Conclusion During the development of diabetes, the changes of Mas in rat pancreas islets were detected earlier than ACE2.These findings might be an important therapeutic target in pancreatic disease.

Key words: Rennin-angiotensin system (RAS), pancreas, Mas, ACE2