Atrial Natriuretic Peptide (ANP) Physiology
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- Atrial Natriuretic Peptide (ANP) is a peptide hormone released by cardiomyocytes primarily in the right and left atria of the heart. Release of ANP is stimulated by over-stretching of the atria and thus occurs in contexts of cardiac over-filling. ANP appears to have mild effects on both the Glomerular Filtration Rate (GFR) and the Regulation of Sodium Excretion; however, the physiological significance of these effects is unknown and likely low. Nevertheless, the presence of ANP causes mild vasodilation of the renal afferent arterioles and mild vasoconstriction of the efferent arterioles, thus serving to increase the GFR. Additionally, ANP acts on the late distal tubule and collecting ductss to reduce sodium resorption, likely by reducing the number of luminal sodium channels on Principal Cells.