Early changes in L-arginine-nitric oxide metabolic pathways in response to the whole-body gamma irradiation of rats
Abstrakt
Nitric oxide (NO), a reactive radical, is formed in higher amounts from L-arginine by inducible NO synthase (iNOS) during early response to ionizing radiation (IR) presumably as a part of signal transduction pathways. This study investigated the changes in L-arginine-NO metabolic pathways within a 24-hour period after whole-body IR of rats with the range of low to supra-lethal doses.
Young adult female Wistar rats received either 0-50 Gy whole-body IR or an intraperitoneal injection of bacterial lipopolysaccharide (LPS, 10 mg/kg). Exhaled NO was monitored using chemiluminiscence, nitrite + nitrate (NO(x) and L-arginine were assayed by HPLC, and expression of iNOS was determined using Western blot.
In contrast to the LPS treatment of rats, the radiation-induced changes in L-arginine-NO metabolic pathways are modest, particularly in the airways and lungs. Noninvasive measurement of exhaled NO within a 24-h period following the exposure of rats to IR has no value for biodosimetry.