Little is known about the plasma concentrations of cyclic 3',5'-guanosine monophosphate (cGMP) in patients with cirrhosis. However, plasma cGMP concentrations provide information on cellular cGMP production by particulate guanylyl cyclases (which are stimulated by natriuretic peptides, such as atrial natriuretic peptide; ANP). In contrast, because intracellular cGMP elicits vasorelaxant mechanisms, plasma cGMP concentrations may be related to haemodynamic alterations in patients with cirrhosis. The aim of the present study was to measure plasma cGMP concentrations in patients with cirrhosis and controls and to examine the relationship between cGMP levels and plasma ANP concentrations and haemodynamic values. Plasma concentrations of cGMP and ANP and splanchnic and systemic haemodynamics were measured in 23 subjects; 13 subjects had cirrhosis and 10 were controls. All subjects had normal glomerular filtration. Plasma cGMP concentrations were significantly higher in patients (6.5 +/- 0.8 pmol/mL) than in controls (2.7 +/- 0.4 pmol/mL), while plasma ANP concentrations did not significantly differ between the two groups (127 +/- 22 and 123 +/- 27 pg/mL, respectively). In patients with cirrhosis, no significant correlation was found between plasma cGMP concentrations and plasma ANP concentrations, hepatic venous pressure gradient, cardiac output or systemic vascular resistance. In conclusion, in patients with cirrhosis, increased plasma cGMP concentrations may be due to an activation of particulate guanylyl cyclases by natriuretic peptides other than ANP. The present study suggest that plasma cGMP concentrations are not related to cirrhosis-induced haemodynamic alterations.