Effects of cysteamine and of irradiation on microsomal membrane-bound enzymes.
Changes in lipid peroxidation, drug-metabolizing enzymes and kinetic constants of ethylmorphine demethylation and of ethylmorphine interaction with cytochrome P-450 were examined after gamma-irradiation. The radiation-induced lipid peroxidation was increased with increasing radiation dose, while cytochrome P-450 content and ethylmorphine demethylase activity decreased. Of the enzyme kinetics parameters, Vmax was modified. Cysteamine protected against the effects of irradiation. This compound interacts with cytochrome P-450 and inhibits the drug-metabolizing enzyme system. Mechanisms of radiation damage, protective and toxic properties of cysteamine are discussed.
D000818:Animals; D003543:Cysteamine / Q000494:pharmacology*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D005037:Ethylmorphine-N-Demethylase / Q000378:metabolism; D005720:Gamma Rays; D007425:Intracellular Membranes / Q000187:drug effects / Q000201:enzymology* / Q000528:radiation effects; D050356:Lipid Metabolism; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology* / Q000528:radiation effects; D011837:Radiation-Protective Agents; D051381:Rats; D011919:Rats, Inbred Strains
D011837:Radiation-Protective Agents; D003543:Cysteamine; D003577:Cytochrome P-450 Enzyme System; D005037:Ethylmorphine-N-Demethylase