Regional differences of atrial natriuretic factors in humans

During sinus coronarius catheterization in humans undergoing diagnostic right-sided cardiac catheterization, levels of atrial natriuretic factor (ANF) measured in sinus coronarius (n = 12) were four times higher than in peripheral arterial blood. Atrial natriuretic factor underwent average extractions of 0.57, 0.40, and 0.28 in the kidneys (n = 14), liver (n = 15), and forearm (n = 15) respectively. However, a close relationship was observed between arterial and peripheral venous concentrations. The substantial clearance of ANF even over the forearm indicates that arterial sampling may be preferred in conditions with altered peripheral vascular resistance, since an uptake of ANF in the peripheral vascular bed is likely to have occurred.