Plasma renin activity and changes in tissue angiotensin converting enzyme

Area of Science:

• Cardiovascular research
• Renal physiology
• Enzymology

Background:

• Tissue angiotensin generation is influenced by plasma renin-angiotensin system components and local tissue-specific processes.
• Understanding the relationship between plasma renin activity (PRA) and tissue angiotensin converting enzyme (ACE) activity is crucial for elucidating local angiotensin II formation.

Purpose of the Study:

• To investigate the relationship between plasma renin activity (PRA) and tissue ACE activity in the heart, lung, kidney cortex, and kidney medulla of Wistar-Kyoto rats.
• To examine renal brush-border ACE activity in the kidney cortex.

Main Methods:

• Utilized experimental models affecting PRA: salt intake variations, deoxycorticosterone acetate (DOCA) with/without salt, and the Goldblatt two-kidney, one clip (2-K,1C) model.
• Measured PRA, plasma ACE activity, and tissue ACE activity in Wistar-Kyoto rats after two weeks of experimental manipulation.

Main Results:

• Blood pressure did not significantly differ between treated rats and controls.
• PRA levels varied as expected across experimental groups (highest in 2-K,1C and depleted-salt; lowest in DOCA, DOCA-salt, and high-salt).
• Tissue ACE activity showed organ-specific responses, independent of PRA. For instance, DOCA treatment increased cardiac and renal ACE only with high salt intake. Clipped kidneys in the 2-K,1C model showed increased ACE activity.

Conclusions:

• Variations in ACE activity are organ-specific.
• Tissue ACE activity was not directly linked to changes in PRA or the development of hypertension in this study.