[Atrial natriuretic factor and water-sodium homeostasis: concepts and perspectives]

The discovery of an endocrine activity of the heart in 1981 was fundamental in order to understand the regulation of the effective circulatory volume. Indeed, the hormone which is secreted by the atrial cells (ANF) when these are distended suddenly in the presence of an enhanced preload of the heart, acts very rapidly upon the kidneys and the vasomotor tone. Its action restores without delay the effective circulatory volume following the renal elimination of an appropriate fraction of salt and water and attenuates the pressor effects of the increased intravascular volume. In this regard, the hormone is an emergency mediator. ANF may also be a long-term regulator of salt and water homeostasis by modulating the renal excretion of sodium. Finally, its role in pathological conditions such as congestive heart failure or essential hypertension remains to be elucidated. Nevertheless, interesting therapeutic perspectives may be considered, based on the unusual inactivation of ANF by clearance receptors.