Measurement of angiotensin metabolites in organ bath and cell culture experiments by liquid chromatography - electrospray ionization - mass spectrometry (LC-ESI-MS).

The metabolism of renin-angiotensin system (RAS) is more complicated than previously expected and understanding the biological phenomena regulated by variety of angiotensin metabolites requires their precise and possibly comprehensive quantitation. Physiological concentrations of angiotensins (Ang) in biological fluids are low, therefore their accurate measurements require very sensitive and specific analytical methods. In this study we developed an accurate and reproducible method of quantitation of angiotensin metabolites through coupling of liquid chromatography and electrospray ionization - mass spectrometry (LC-ESI-MS). With this method main angiotensin metabolites (Ang I, II, III, IV, 1-9, 1-7, 1-5) can be reliably measured in organ bath of rat tissues (aorta, renal artery, periaortal adipose tissue) and in medium of cultured endothelial cells (EA.hy926), exposed to Ang I for 15 minutes, in the absence or in the presence of angiotensin converting enzyme inhibitor, perindoprilat. Presented LC-ESI-MS method proved to be a quick and reliable solution to comprehensive analysis of angiotensin metabolism in biological samples.