Atrial natriuretic peptide (ANP) is a hormone produced by cells in the heart's atria that helps regulate blood pressure and fluid balance in the body. Also known as atrial natriuretic factor (ANF), ANP works by promoting the excretion of sodium and water by the kidneys, which helps reduce blood volume and pressure. Other synonyms for ANP include cardionatrin, atriopeptin, and atrial natriuretic factor alpha, among others. ANP is an important diagnostic marker for conditions such as heart failure, hypertension, and renal disease, and its role in regulating fluid and electrolyte balance makes it a potential target for therapeutic interventions.