Brief Communication Localization of Angiotensinogen Messenger RNA in Rat Aorta

The distribution of angiotensinogen messenger (mRNA) was determined in the rat aorta. Other investigators have demonstrated the presence of angiotensinogen mRNA in whole rat aorta; however, its precise location in the blood vessel wall has not been defined. When various layers of the vessel wall were separated by dissection or cell dispersion, angiotensinogen mRNA levels were greatest in the periaortic adipose tissue. Angiotensinogen mRNA was present in very small levels in the adventitia, with no detectable levels in the muscle layer. In addition to periaortic adipose tissue, angiotensinogen mRNA was also present in the interscapular brown fat pad of the rat. The high levels of angiotensino-gen mRNA in periaortic brown adipose tissue suggests that angiotensin may be synthesized there and responses may exist in this tissue or adjacent sympathetic nerve terminals. {Circulation Research 1988;62:1259-1262) A ngiotensinogen is the only known precursor to / \ the angiotensin peptides. The presence of an-A. \- giotensinogen messenger RNA (mRNA) in a tissue implies the ability to synthesize this protein, an obligatory requirement in the ultimate production o