Atrial natriuretic peptide

The Atrial Natriuretic Peptide belongs to the so-called "natriuretic peptides" of the heart (see also BNP, CNP). ANP ensures that sodium is excreted via the kidneys. ANP is an opponent of the blood pressure-increasing renin-angiotensin-aldosterone system. The peptide is mainly formed in cardiomyocytes (myocytes) of the atria when the atria of the heart are dilated and released into the blood. ANP is also produced by immune cells and performs functions in innate and adaptive immunity.

ANP is important for the body's water and salt balance and for blood pressure. It is the antagonist of the system in the body that causes blood pressure to rise, namely the so-called "renin-angiotensin-aldosterone system". ANP inhibits the release of renin (a hormone of the kidney that causes blood pressure to rise) and aldosterone (a hormone of the adrenal cortex that prevents sodium from being excreted through the kidney). It also has a vasodilating effect (vasodilatation). By activating membrane-bound guanyl cyclases, ANP induces an increase in intracellular cGMP concentration. cGMP activates the cGMP-dependent protein kinase (PRKG1), which activates ATP-dependent calcium pumps in the cell membrane through phosphorylation. Calcium ions are increasingly transported out of the cell. This leads to the relaxation of smooth muscles.

The ANP-encoding gene (ANP gene) codes for a 151 amino acid prepro-ANP. By splitting off an N-terminal signal peptide (25 amino acids), pro-ANP is formed. Corin, a membrane-bound serine protease, cleaves ANP from the C-terminal (28 amino acids) in a final step.

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