The presence of a renln-angiotensin system in the central nervous system (CNS) has been demonstrated by several investigators, but little is known regarding the origin of its components. In this study we have compared the immunological and physical-chemical nature of angiotensinogen in plasma and cerebrospinal fluid (CSF) of human subjects and explored whether differences are present in CSF angiotensinogen concentrations of normal and hypertensive subjects. No significant differences in the

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... re of plasma and CSF angiotensinogen was observed with respect to molecular weight (65-70,000) electrophoretic mobility (Rfaib -0.67 ± 0.003) or angiotensin I (AI) generated (pi = 6.6). Following isoelectric focusing, the plasma angiotensinogen was shown to consist of a single component with an isoionic point of 4.40 ± 0.04. CSF angiotensinogen, on the other hand, resolved into three components (pi = 4.76 ± 0.02; 5.16 ± 0.04; 5.76 ± 0.04). Although no correlations were observed between angiotensinogen levels in the CSF or plasma with blood pressure (BP), a statistically significant difference in angiotensinogen concentration of both plasma and CSF was observed between normotensive and hypertensive subjects. The differences in the chemical and immunological nature of human plasma and CSF angiotensinogens suggest that the angiotensinogen of CSF is not of peripheral origin. (Hypertension 2: 432-436, 1980) KEY WORDS • angiotensinogen • cerebrospinal fluid • isoelectric focusing