Objective:To investigate the effects of calcium antagonist
nifedipine(NF)on insulin receptors in rat
hepatocytic membrane
and explore the effects of NF on biological action of insulin.Methods:Exp 1:The rat livers were perfused with different concentrations of NF(0 5,1 0, and 10 0μmol/L),and the preparation of
hepatocytic membrane was produced for measuring the binding capacity of insulin receptors by radioimmunoassay Exp 2: The hepatocytic membrane samples from non NF treated were reacted with different concentrations of NF for measuring the binding capacity of insulin receptor.Results:Exp 1 showed that the maximal binding capacity (Bmax), affinity constant (K 1 ) and binding sites(Q 1 ) of higher affinity receptor were not influenced by 3 scale concentrations of NF, whereas, the affinity constant(K 2 )of lower affinity receptor was elevated in manner of NF dose dependence, and the binding sites(Q 2 )of lower affinity receptor were reduced Exp 2 showed that the Bmax , Q 1 ,Q 2 and K 2 were decreased by 3 scale concentrations of NF in a manner of dose dependence, and the higher concentrations of NF lowered K 1 either. Conclusion:NF influenced the binding capacity of insulin receptor in the hepatocytic membrane at some extent by means of the direct reaction.