THE SITE OF ANGIOTONIN DESTRUCTION

Area of Science:

• Physiology
• Biochemistry

Background:

• Angiotonase is an enzyme involved in angiotonin metabolism.
• The exact site of angiotonin destruction in vivo is not fully understood.

Purpose of the Study:

• To investigate the role of plasma and red blood cells in angiotonin destruction.
• To determine the physiological significance of angiotoninase activity.

Main Methods:

• Assessing pressor response to angiotonin after various physiological manipulations (nephrectomy, evisceration, hemorrhage, hemodilution, shock).
• In vitro studies on the angiotonin-degrading activity of intact and hemolyzed red blood cells compared to plasma.
• Investigating the effect of intravascular hemolysis on angiotonin response.

Main Results:

• Nephrectomy and evisceration had minimal impact on angiotonin response.
• Hemorrhage and hemodilution increased angiotonin response, suggesting plasma removal is key.
• Intact red cells showed no angiotoninase activity, but hemolyzed cells were highly active.
• Intravascular hemolysis reduced angiotonin response, supporting plasma as the primary site of destruction.
• The active principle in hemolyzed blood was heat-labile.

Conclusions:

• The majority of angiotonin destruction occurs in the plasma under physiological conditions.
• Red blood cells, particularly after hemolysis, play a less significant role in vivo compared to plasma.
• These findings highlight the critical role of plasma angiotonase in regulating angiotonin levels.