For a long time, we thought of the heart solely as a muscular pump that ensures blood circulation. Today we know it is much more: a true endocrine organ, capable of sending chemical signals that affect the entire body.
The heart and its hormonal language
The heart produces and secretes key hormones. The best known is atrial natriuretic peptide (ANP), released by cells in the atria when they detect distension due to an increase in blood volume. Its counterpart, ventricular BNP, also has powerful systemic effects. Adolfo de Bold, a physiologist, was the first to identify this endocrine function of the heart in 1981, a discovery published in Life Sciences that transformed cardiology.
These hormones promote renal sodium elimination, inhibit renin and aldosterone secretion, induce vasodilation, and actively regulate blood pressure and blood volume.
Cellular messengers that transform physiology
These peptides act through membrane receptors with guanylate cyclase activity, increasing intracellular cGMP, a messenger that protects the cardiovascular system through antiproliferative, antifibrotic, and anti-inflammatory effects, as documented by Lincoln Potter in Endocrine Reviews.
In addition, other mediators such as neurotensin, adrenomedullin, or circulating cardiomyocyte microRNAs amplify this endocrine activity, affecting metabolism, immune response, and neurohormonal communication.
Heart, brain and kidneys: an integrated network
The heart does more than just pump blood. It perceives mechanical and chemical signals, responds with hormonal messages, and modulates central functions such as thirst, appetite, and even certain emotional states. This neuroendocrine interconnection between the heart, brain, and kidneys is what medicine describes as the cardiorenal axis. Claudio Ronco, a leading nephrologist in the study of cardiorenal syndrome, has been one of the principal authors in systematizing this syndrome in the Journal of the American College of Cardiology.
Andrew Armour, a pioneer in neurocardiology, documented that the heart possesses approximately 40,000 sensory neurons that process information autonomously. The heart does not passively receive instructions. It sends more information to the brain than it receives, through vagal afferent pathways that modulate emotional, cognitive, and perceptual responses.
Medical perspectives and biomarkers
This endocrine view of the heart has been validated by numerous clinical and experimental studies. Its implications are enormous in cardiology, nephrology, and endocrinology. BNP levels have become fundamental biomarkers for the diagnosis and monitoring of heart failure, as established by cardiologist Alan Maisel and his colleagues in a landmark study published in the New England Journal of Medicine.
The heart as an endocrine organ is not a hypothesis. It is established clinical science.
When we understand the heart in this way, we stop seeing it as a simple engine. It is a center of perception, communication, and regulation that connects the cardiovascular system with metabolism, the brain, and the autonomic nervous system. Each heartbeat is not just movement. It is information.
Sources and references
Armour, J. A. (2007). The little brain on the heart. Cleveland Clinic Journal of Medicine, 74(Suppl 1), S48-S51. Cardiologist, pioneer in neurocardiology.
De Bold, A.J. et al. (1981). A rapid and potent natriuretic response to intravenous injection of atrial myocardial extract in rats. Life Sciences, 28(1), 89-94. PhD in physiology, University of Ottawa.
Maisel, AS et al. (2002). Rapid measurement of B-type natriuretic peptide in the emergency diagnosis of heart failure. New England Journal of Medicine, 347(3), 161-167. MD cardiologist, University of California San Diego.
Porges, S. W. (2011). The Polyvagal Theory. W. W. Norton. PhD, neuroscientist, Indiana University.
Potter, L.R. et al. (2006). Natriuretic peptides, their receptors, and cyclic guanosine monophosphate-dependent signaling functions. Endocrine Reviews, 27(1), 47-72. PhD in pharmacology, University of Minnesota.
Ronco, C. et al. (2008). Cardiorenal syndrome. Journal of the American College of Cardiology, 52(19), 1527-1539. MD nephrologist, University of Padua.