Endothelial cells secrete various substances, notably plasminogen activator.
Endothelial cells are a dynamic and crucial part of the circulatory system. Besides their structural role lining blood vessels, they actively synthesize and secrete a variety of molecules that influence various physiological processes.
Here's a breakdown of the key secretions and functions of endothelial cells:
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Plasminogen Activator: As highlighted in the reference, endothelial cells secrete plasminogen activator. This enzyme is vital for fibrinolysis, the process that breaks down blood clots.
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Angiotensin-Converting Enzyme (ACE): Endothelial cells synthesize ACE, a key enzyme in the renin-angiotensin-aldosterone system (RAAS). ACE converts angiotensin I to angiotensin II, a potent vasoconstrictor, which plays a significant role in blood pressure regulation.
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Growth Factors and Other Substances: While not explicitly mentioned in the provided snippet, endothelial cells also secrete other growth factors and substances that influence:
- The growth of other cells.
- Inflammation.
- Vascular permeability.
- Regulation of blood vessel tone.
In addition to secreting these substances, endothelial cells also:
- Bind lipoproteins and hormones.
- Serve as targets for and participate in immune reactions.
In summary, endothelial cells are active secretory cells, playing a far more complex role than simply forming a barrier within blood vessels. Their secretions and other functions make them key regulators of vascular function, blood pressure, coagulation, and inflammation.
