Atria1 Natriuretic Factor: Its Role in Hypertension*

The story of the atrial natriuretic factor is a fascinating one. Over an extremely short time. a putative hormone was suggested. its biochemical characteristics were identified. the amino acid sequence was determined, the peptide was cloned and the pure hormone was made available through recombinant technology. Thus, thanks to modern day high technology, a new hormone, one originating in the heart. was identified and commercially synthesized. Yet industry became frustrated because the commercial potential of atria1 natriuretic factor made available through “high tech” developments outpaced the physiologic knowledge about its role in health and disease. The latter requires the luxury of time to permit acquisition of biologic (e.g., physiologic, biochemical) information, scientific interchange at meetings and in publications and, of course, confirmation of the data. It is inevitable that this experience will recur in the future. Pathophysiology of atrial natriuretic factor. In this issue of the Journal (1) we are presented with new physiologic information concerning the role of atrial natriuretic factor in health and disease. Before commenting on this article, I will examine briefly the teleology of the pathophysiology of atrial natriuretic factor. Consider the circumstances of a volumeoverloaded circulation. Here we find a situation of an increased venous return to the heart and an expanded cardiopulmonarv volume. Ideally, if the heart could “sense” this overload in-its low pressure chamber and then initiate a response to induce natriuresis and diuresis, this would provide the negative feedback that we expect from finely tuned circulatory homeostasis. Indeed, we now know that atrial stretch associated with volume overload serves to release atrial natriuretic factor from the atrium: this, in turn, stimulates the renal excretion of sodium (and water), which restores a normal cardiopulmonary volume and circulation (2). However, the foregoing events are only partially true and