Characterization of angiotensin I, II, and III from mouse as position-5 isoleucine [Ile5] angiotensins. An HPLC Study.

Angiotensin I was generated in vitro in mouse plasma by addition of mouse submaxillary renin. After deproteinization on Dowex 50W-X2 ion exchange resin, the samples were separated by reverse phase liquid chromatography and the fractions analysed by radio-immunoassay for angiotensin I. Angiotensin I from mouse was injected into the jugular vein of a nephrectomized rat in order to generate angiotensin II and III of mouse origin. Carotid arterial blood was collected immediately, centrifuged and the plasma deproteinized and separated on high pressure liquid chromatography (HPLC). The fractions were analysed for angiotensin I, II and III by radioimmunoassays. Retention times for mouse angiotensins in the liquid chromatography system were compared to synthetic [Val5] and [Ile5] angiotensin I, II and III. All three mouse angiotensins coincided with the corresponding synthetic [Ile5] angiotensins during elution, suggesting the same type of angiotensin in mouse and man. An additional study on rat angiotensins confirmed previous findings by other investigators, indicating that the angiotensins of this animal were also of the [Ile5] type.