ANP

Where it comes from

Made in

Muscle cells of the heart’s atria, where it waits in granules

Sent out by

Stretch of the atrial wall when blood volume or pressure rises

Acts on

• Kidney
• Blood vessels
• Adrenal cortex
• Heart

What it does

• Makes the kidney pass more sodium and water
• Relaxes blood vessels, lowering the pressure the heart pumps against ¹
• Dampens the renin-angiotensin-aldosterone system

In medicine

• Sacubitril, in Entresto, blocks neprilysin, the enzyme that destroys natriuretic peptides, to treat heart failure ²
• Carperitide, recombinant ANP, is used for acute heart failure in Japan
• A common NPPA variant, rs5065, lengthens ANP by two amino acids; it is one of the Peptide genes cards in the Evigenics report

Beyond the body’s own use

• ANP is hard to measure, so laboratories measure MR-proANP, a stable fragment of its precursor instead; in 1,641 patients with acute breathlessness it was non-inferior to BNP for diagnosing heart failure, at a threshold of 120 pmol/L ³
• Nesiritide, a recombinant form of the sister peptide BNP, was given for acute heart failure for a decade until a 7,141-patient trial found no effect on breathlessness or death; it is no longer marketed in the United States ⁴
• Medicine now works this system by stopping the peptides being destroyed rather than by giving them, because an infused natriuretic peptide lasts only minutes ²
• There is no grey market in ANP, and could not be: it is digested if swallowed and gone from the blood within minutes of an injection ¹