Induction of radical scavenging ability and protection against radiation-induced damage to microsomal membranes following low-dose irradiation.
OBJECTIVE
To investigate changes in rat liver cytosolic radical scavenging ability and in microsomal membrane function following low doses of radiation.


METHODS
Wistar rats were irradiated with 1-50 cGy of X-rays and liver cytosolic radical scavenging ability was determined using DPPH, a stable free radical. Liver microsomal drug metabolizing activity was determined using hexobarbital as a substrate. Cytosolic antioxidants and microsomal enzymes were spectrophotometrically determined.


RESULTS
Irradiation of rats at around 5-10 cGy induced liver cytosolic radical scavenging ability and a considerable increase in this ability at 5 cGy was observed for 3 days after irradiation. Glutathione reductase was suggested as a candidate of cytosolic antioxidants. Radiation-induced damage to liver microsomal drug metabolizing enzyme activity was suppressed by preirradiation with 5 cGy, mainly by protecting cytochrome P-450.


CONCLUSIONS
Low doses of radiation increased cytosolic radical scavenging ability and resulted in protection of microsomal membrane function which is easily damaged by radiation-induced free radicals.
Yukawa
O
O
Division of Biology and Oncology, National Institute of Radiological Sciences, Japan. yukawa@nirs.go.jp
Nakajima
T
T
Yukawa
M
M
Ozawa
T
T
Yamada
T
T
D000818:Animals; D002462:Cell Membrane / Q000528:radiation effects; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004307:Dose-Response Relationship, Radiation; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology / Q000528:radiation effects*; D009249:NADP / Q000378:metabolism; D011835:Radiation Protection; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase / Q000378:metabolism
D017382:Reactive Oxygen Species; D009249:NADP; D003577:Cytochrome P-450 Enzyme System; D013482:Superoxide Dismutase