Atrial natriuretic peptide (ANP) has vasodilatory, natriuretic, and diuretic properties and is secreted in response to atrial wall distension and thereby provides an indirect evaluation of central blood volume (CBV). Adrenaline possesses chronotropic and inotropic effects which increases cardiac output (CO). The present study evaluated whether these effects are influenced by an increase in CBV and reflected in mid-regional proANP (MR-proANP)  concentrations in circulation, a stable proxy marker of bioactive ANP. Changes in CBV were evaluated by thoracic electrical admittance (TEA) and haemodynamic variables monitored by pulse-contour analysis during two intervals with graded infusion of adrenaline. Adrenaline infusion increased heart rate (33 ± 18%), stroke volume (6 ± 13%) and thereby CO (42 ± 23%, all P < 0.05). The increase in CO did, however, not result from an increase in CBV as TEA remained stable (-3 ± 17%, P = 0.230). Serum MR-proANP concentrations increased (26 ± 25%; P < 0.001) by adrenaline infusion and remained elevated 60 min thereafter. Thus, MR-proANP in circulation is not only affected by CBV but also by increased chronotropy/inotropy of the heart or adrenaline directly induces release of ANP variants from the myocytes. This article is protected by copyright. All rights reserved.