Atriopeptin I, rat

Atriopeptin is a 28 amino acid peptide synthesized primarily in cardiac atria. Atriopeptin acts in opposition to angiotensin II in regulating renal, hemodynamic, and endocrine function. Atriopeptin is released in response to the increased pressure and mechanical stretch of the right atrium due to blood volume overload. Atriopeptin then acts at the nephron to increase salt and water excretion, lowering blood volume and blood pressure. Elevated plasma atriopeptin levels may be produced in experimental models by volume expansion, high salt diets, and in response to vasoconstrictors. Increased plasma concentrations have also been reported in various pathological conditions such as renal disease, congestive heart failure, and paroxysmal atrial tachycardia.