ANP (atrial natriuretic peptide) is a hormone that is secreted by the cells of the atria of the heart. The heart contains specialized cells called atrial myocytes, which release ANP in response to changes in blood pressure and blood volume.
When blood volume or blood pressure increases, the atrial myocytes are stretched, which triggers the release of ANP. ANP acts to reduce blood volume and blood pressure by increasing the excretion of sodium and water by the kidneys, which in turn reduces the amount of fluid in the body.
ANP also has other effects on the cardiovascular system, including the relaxation of blood vessels and the inhibition of the production of other hormones, such as renin and aldosterone, that can raise blood pressure. ANP plays an important role in the regulation of blood pressure and fluid balance in the body.
