Objective: To investigate the changes of alpha-1 adrenergic receptors in cirrhotic liver and the relationship between the changes and the pathogenesis of portal hypertension.
Methods: The concentration and affinity of alpha-1 adrenergic receptors in the liver plasma membranes of posthepatitic cirrhotic patients with portal hypertension were quantitatively measured using radioligand binding analysis.
Results: Compared with 8 controls without hepatic pathological changes, the maximal binding capacity (Bmax) of 9 posthepatitic cirrhotic patients decreased (129.1 +/- 12.0 vs 142.1 +/- 14.1 fmol/mg protein, P > 0.05), dissociation constant (Kd) values increased (0.3945 +/- 0.0974 vs 0.2382 +/- 0.0548 nmol/L, P < 0.01), and the receptor maximal content (RMC) decreased (417.4 +/- 76.8 vs 739.9 +/- 167.6 fmol/g liver, P < 0.01).
Conclusions: The decreased concentration and affinity of alpha-1 adrenergic receptors may play an important role in the metabolic disturbances of catecholamines often seen in some cirrhotic patients, and have implications in the pathogenesis of portal hypertension.