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Which hormones and enzymes are produced by the kidneys?

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Human kidneys — renal system Diagram showing the location of the kidneys in the abdominal cavity and their attachment to major arteries and veins.

The kidneys perform essential nonexcretory functions by producing several hormones and enzymes that regulate blood pressure, red blood cell production, and mineral metabolism.1

Hormones and Enzymes Produced by the Kidneys

Renin: This is an enzyme secreted by the juxtaglomerular apparatus in the kidney. It plays a critical role in the renin–angiotensin system by acting on plasma globulins to initiate the production of angiotensin II, a potent vasoconstrictor that raises blood pressure.23
Erythropoietin: This hormone is produced largely in the kidneys. It is released in response to low oxygen levels or decreased red blood cell counts, traveling to the bone marrow to stimulate the production of red blood cells.41
1,25-dihydroxycholecalciferol (Calcitriol): The kidneys produce this metabolically active form of vitamin D. This process is stimulated by parathyroid hormone and is essential for increasing calcium absorption in the gastrointestinal tract.15
Prostaglandins: These hormonelike fatty acids are synthesized within kidney tissues to exert local effects. For example, the renal cortex produces prostacyclin (PGI₂), which helps maintain renal blood flow.2
Kallikrein: This enzyme is secreted by the renal tubules and added to the urine, where it activates the conversion of kininogen to bradykinin, a vasodilator.2