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Plasma Renin Activity

Meaning

Plasma Renin Activity (PRA) is a clinical measurement quantifying the rate at which the enzyme renin, secreted by the juxtaglomerular cells of the kidney, catalyzes the conversion of angiotensinogen to angiotensin I in the blood plasma. This activity is a crucial indicator of the function and activation status of the Renin-Angiotensin-Aldosterone System (RAAS), the body’s primary hormonal cascade for regulating blood pressure and fluid-electrolyte balance. High PRA often suggests a state of volume depletion or excessive sympathetic nervous system stimulation, while suppressed PRA can indicate primary mineralocorticoid excess. It provides essential diagnostic insight into the etiology of hypertension and fluid disorders.