Renin blood pressure - Google Search : "Renin's primary function is therefore to eventually cause an increase in blood pressure, leading to restoration of perfusion pressure in the kidneys. Renin is secreted from juxtaglomerular kidney cells, which sense changes in renal perfusion pressure, via stretch receptors in the vascular walls. " How does renin cause high blood pressure? Renin converts angiotensinogen, which is produced in the liver, to the hormone angiotensin I. An enzyme known as ACE or angiotensin-converting enzyme found in the lungs metabolizes angiotensin I into angiotensin II. Angiotensin II causes blood vessels to constrict and blood pressure to increase. What does a high renin level mean? Renin is a protein (enzyme) released by special kidney cells when you have a decreased salt (sodium) level or low blood volume. If you have high blood pressure, your doctor may order a renin and aldosterone test to help determine the cause of your elevated blood press