Cardiovascular & natriuretic
The heart as an endocrine organ — releasing peptides to shed the load that stretches it.
ANP · BNP · CNP
Overview
The heart is also an endocrine organ. When its chambers stretch under volume or pressure load, cardiac myocytes release natriuretic peptides that promote sodium and water excretion and relax blood vessels — lowering the load that triggered them.
ANP and BNP act through a guanylyl-cyclase-linked receptor to raise cGMP; BNP's blood level is a routine clinical marker of heart failure. Alongside them sit the vasoactive peptides angiotensin II and endothelin-1, which push the other way.
Key signals
Reference notes
- Natriuretic peptides signal through membrane guanylyl-cyclase receptors (NPR-A/B), raising cGMP — a different second messenger from the cAMP/GPCR families.
- BNP and its NT-proBNP fragment are standard heart-failure biomarkers.
- Angiotensin II and endothelin-1 are the opposing vasoconstrictor peptides in this system.