Definition of renin in US English:



  • An enzyme secreted by and stored in the kidneys which promotes the production of the protein angiotensin.

    • ‘By causing volume and sodium depletion, thiazide diuretics stimulate the production of renin and angiotensin.’
    • ‘By regulating salt levels through production of an enzyme called renin (as well as other substances), the kidneys ensure that blood pressure is regulated.’
    • ‘Angiotensinogen, the initial substrate of the renin-angiotensin-aldosterone system, is produced in the liver; renin converts it to angiotensin I in the kidneys.’
    • ‘The greatest cause is probably due to lower production of hormones such as renin, angiotensin and aldosterone, caused by the increased stress (these hormones assist the body in retaining fluid).’
    • ‘All these changes act directly or indirectly as stimuli for the release of the enzyme renin in the kidneys, triggering a sequence of chemical events in the blood of which the end product is angiotensin II.’


Late 19th century: from Latin ren ‘kidney’ + -in.