[Changes of histamine receptors in the liver of the rat during the development of experimental cirrhosis].

It remains unknown whether changes of histamine H1 and H2 recepters in the liver occur during the development of cirrhosis. 48 male Wistar rats were divided, equally and randomly, into experiment and control groups, and the rats in the experiment group were induced by CCl4 to form experimental cirrhosis models. Then, at different stages during the development of experimental cirrhosis, the maximal binding capacity (Bmax), dissociation constants (Kd), and binding ability (BA = Bmax/Kd) of histamine H1 and H2 receptors in the livers of the two groups were analysed by radioligand binding assay. At early stage of the development of experimental cirrhosis, the Bmax of H2 receptor in the rat liver was not statistically different from that of normal control; at middle and advanced stages of the course, the Bmax of H2 recepter were significantly lower than normal. The Bmax of H1 receptor was obviously lower than normal at each stage. At middle stage, the Kd of H1 receptor was significantly higher than normal, whereas the Kd of H1 receptor at the other two stages and the Kd of H2 receptor at each stage were not remarkably different from those of the controls. At each stage of the development of experimental cirrhosis, the BA of H1 and H2 receptor was all significantly lower than that of the normal controls. It was concluded that the "down-regulation" of the receptors may be an important factor for the reduction of Bmax and BA of the two histamine receptors, and these changes of the receptors may possibly led to metabolic disorder of carbohydrates and phospholipid in the liver and lower the liver's ability to inactivate histamine.