37kDa (340 amino acids)

Renin, also known as angiotensinogenase is an aspartic protease enzyme which cleaves angiotensinogen and yields the decapeptide angiotensin I. Pro-renin has also a receptor so it may be considered a hormone too. Renin is secreted by the juxtaglomerular cells, a specialized smooth muscle cell located in the wall the afferent arterioles.

3 stimuli promote its secretion:

• Decreased blood pressure sensed by the walls of the afferent arterioles
• Decreased sodium chloride load at the level of the macula densa
• Sympathetic nervous system activity through β1 adrenergic receptors

Picture obtained from the public domain. Courtesy link

References

Wikipedia contributors. "Renin". Wikipedia, The Free Encyclopedia. Accessed February 16, 2020. https://en.wikipedia.org/wiki/Renin

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