BNP (B-type natriuretic peptide) released from ventricles under stress
The heart also produces BNP (B-type natriuretic peptide), released from the ventricles under mechanical stress. This is mentioned alongside other cardiac secretions including endothelin (a vasoconstrictor) and prostaglandins (anti-inflammatory mediators), reinforcing that the heart is a sensing and signaling organ, not merely a pump.