title: Activation of serum complement by contrast media.
abstract: Evidence is presented for the activation of serum complement by contrast media, in vitro and in vivo. Activation as a function of concentration was measured and the increasing order of effectiveness was found to be metrizamide, iothalamate, diatrizoate, acetrizoate, iodipamide and iopanoate. This order is the same as for protein binding and enzyme inhibition. The activation mechanism for iodipamide, and by inference for the other compounds, does not involve gamma-globulin aggregation. Serial daily injections in normal dogs resulted in substantial declines in serum complement over several days. Guinea pigs which were depleted of serum complement with cobra venom factor were found to be no less sensitive to lethal doses of iodipamide than those with normal complement. Implications of these findings are discussed.
mesh_terms: D000100:Acetrizoic Acid / Q000494:pharmacology; D000818:Animals; D003169:Complement Inactivator Proteins; D003165:Complement System Proteins; D003287:Contrast Media / Q000494:pharmacology*; D003973:Diatrizoate / Q000494:pharmacology; D004285:Dogs; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006168:Guinea Pigs; D006801:Humans; D066298:In Vitro Techniques; D007458:Iodipamide / Q000494:pharmacology; D007480:Iopanoic Acid / Q000494:pharmacology; D007483:Iothalamic Acid / Q000494:pharmacology; D008297:Male; D008793:Metrizamide / Q000494:pharmacology; D011485:Protein Binding; D012910:Snake Venoms
chemical_list: D003169:Complement Inactivator Proteins; D003287:Contrast Media; D004791:Enzyme Inhibitors; D012910:Snake Venoms; D003973:Diatrizoate; D007483:Iothalamic Acid; D000100:Acetrizoic Acid; D003165:Complement System Proteins; D007480:Iopanoic Acid; D008793:Metrizamide; D007458:Iodipamide