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Arterial wall renin.
Summary
Renal renin uptake by arteries influences blood pressure, persisting longer than plasma renin. This arterial renin, not plasma levels, correlates with blood pressure changes and responses to inhibitors.
Area of Science:
- Cardiovascular Physiology
- Renal Physiology
- Enzymology
Background:
- Aortic enzymes can release angiotensin I (AI) from renin substrate, independent of renin.
- Renin-like activity in rat aorta parallels plasma renin in steady-state conditions.
- Divergence in aortic and plasma renin activity occurs in non-steady states.
Purpose of the Study:
- To investigate the role of aortic renin-like activity in blood pressure regulation.
- To determine the fate of injected renal renin in nephrectomized rats.
- To assess the relationship between arterial renin and blood pressure responses.
Main Methods:
- Bilateral nephrectomy and injection of renal renin into rats.
- Measurement of aortic and plasma renin-like activity.
- Assessment of blood pressure changes and responses to teprotide.
- Immunofluorescent localization of renin in arterial tissues.
Main Results:
- Aortic renin-like activity cleared slower than plasma renin post-nephrectomy.
- Blood pressure changes correlated with aortic renin-like activity, not plasma renin.
- Arterial renin uptake was predominantly into the media and persisted.
- Teprotide's blood pressure effect was linked to aortic renin-like activity.
Conclusions:
- Uptake and persistence of renal renin in arteries are crucial for renin-angiotensin system physiology.
- Arterial renin mediates renin-induced changes in peripheral resistance and blood pressure.
- No evidence supports renin accumulation in vessel walls causing hypertension at normal circulating levels.