G proteins in rat liver proliferation during cholestasis

摘要: Liver proliferation appears to be dually regulated, in part by cyclic AMP levels. Here we studied the alterations stimulatory action of cholera toxin and other agents on adenylyl cyclase system, as well status Gs Gi protein subunits during liver that follows bile duct ligation rats. The effects glucagon vasoactive intestinal peptide (which act through membrane receptors) or guanosine 5′-[βγ-imido]triphosphate interacts with G proteins) forskolin directly activates catalytic subunit) activity were blunted cholestasis. results indicated an impairment interaction between αs subunit subunit. Indeed, observed important decrease stimulation cholestasis was accompanied a reduced extent [32P]ADP ribosylation catalyzed toxin, revealed poor labeling 42,000 Da band membranes from cholestatic However, there no change amount β proteins measured immunoblotting techniques. Experiments αi rats, whereas Western blotting for detection showed decreased αi3 increased αi2 levels this condition. Further efforts are needed better understand molecular mechanisms underlying relationship divergent expression cell liver. (Hepatology 1994;20:1041–1047).