<Tr> <Th> PubMed </Th> <Td> articles </Td> </Tr> <Tr> <Th> NCBI </Th> <Td> proteins </Td> </Tr> <P> Renin (etymology and pronunciation), also known as an angiotensinogenase, is a serine protease protein and enzyme secreted by the kidneys that participates in the body's renin - angiotensin aldosterone system (RAAS)--also known as the renin - angiotensin - aldosterone axis--that mediates the volume of extracellular fluid (blood plasma, lymph and interstitial fluid), and arterial vasoconstriction . Thus, it regulates the body's mean arterial blood pressure . </P> <P> Renin can be referred to as a hormone even though it has no peripheral receptors and rather has an enzymatic activity with which it hydrolyzes angiotensinogen to angiotensin I . </P>

What part of the kidney senses changes in blood pressure