title: Interaction of the insecticide 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane with the beta-receptor adenylate cyclase system in Chang liver cell membranes.
abstract: Interaction of the insecticide 1,1,1-trichloro-2,2-bis-(p-chlorophenyl)-ethane (DDT) with beta-receptor binding and adenylate cyclase activity of biological membranes has been studied. Following exposure of cultured Chang liver cells to DDT, maximal binding of the catecholamine antagonist [125I]-iodohydroxybenzylpindolol (HYP) to isolated cell membranes was decreased by 30% whereas the dissociation constant remained unchanged. Both basal activity and maximal isoproterenol-stimulated activity of adenylate cyclase were not altered. The isoproterenol concentration required for half-maximal stimulation of the enzyme was increased about 2-fold as was the agonist concentration required for half-maximal displacement of the antagonist HYP at the beta-receptor binding site. Thus, coupling efficiency of hormone-stimulated adenylate cyclase activity was not influenced by the presence of DDT in these membranes. The data show that interaction of DDT with the beta-receptor adenylate cyclase complex is restricted to the receptor component. Enzyme activity is directly linked to changes of agonist binding at the beta-receptor. Interference of DDT with signal transduction via 'fluidization' of membrane lipids has not been detected.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D003634:DDT / Q000494:pharmacology*; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D010869:Pindolol / Q000031:analogs & derivatives / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000187:drug effects* / Q000378:metabolism
chemical_list: D011943:Receptors, Adrenergic, beta; C011878:iodohydroxybenzylpindolol; D010869:Pindolol; D003634:DDT; D000262:Adenylyl Cyclases; D007545:Isoproterenol