Nitric oxide and iron overload - Limitations of ESR detection by DETC

The ability of the ESR technique based on diethyldithiocarbamate (DETC) adm inistration was studied as a suitable method to assess NO generation in viv o. The technique was successfully employed to measure NO generation after L PS treatment. DETC2-Fe-NO adducts were detected in liver homogenates of iro n overloaded animals. When iron was administered to the animals simultaneou sly with LPS. NO-dependent signal increased 122%, but the content of NO2 an d NO3 in sera was significantly lower (44%) as compared to LPS-treated rats . Iron dextran administration was responsible for a three-fold increase in the DETC2-Fe-NO content in non-LPS treated rats, while NOS activity and ser a NO2- and NO3- levels remained unaffected. The adduct generation rate by a chemical NO-source was recorded in the presence of either control or iron overloaded homogenates supplemented with DETC in vivo. The exposure of live r homogenates to NO was performed either by the addition of 1 mM SNAP as NO donor or infusing an aqueous NO solution. In the presence of iron overload ed samples the adduct generation rate was 3.8-4.4-fold higher than in the p resence of control samples. This effect restricts the applicability of the method to experimental conditions where iron levels remain constant. theref ore it is not suitable for NO generation studies in experimental models whe re animals were subjected to iron overload. (C) 2001 Published by Elsevier Science Ireland Ltd.