Immunohistochemical research on the atrial natriuretic factor (ANF) in rat atrioventricular valves.

Immunohistochemical research on atrioventricular valves in normotensive rats revealed that valvular myocardiocytes are the seat of synthesis of the atrial natriuretic factor (ANF). The endocardial cells that border the atrial and ventricular surfaces also had granules which were positive for ANF. The ANF which is also synthesized in the valvular myocardiocytes moved towards the cardiac cavity and crossed the endocardial cells in the more distal areas of the valvular edge. At the same time, the ANF was routed into the blood vessels in the areas close to implantation.