M. Laloraya et al., ESTROGEN SURGE - A REGULATORY SWITCH FOR SUPEROXIDE RADICAL GENERATION AT IMPLANTATION, Biochemistry and molecular biology international, 39(5), 1996, pp. 933-940
This study is undertaken to identify the regulatory switch for the act
ivation of superoxide radical generation pathway and repression of sup
eroxide dismutase (SOD) at the time of implantation using estrogen as
a control factor and delayed implantation as a model system. The resul
ts revealed high SOD activity anl negligible oxyradical generation in
progesterone-treated animals on day-5 and day-8 (delayed implantation)
while an enormous rise in oxyradical generation and an abrupt fall in
SOD in animals which received both estrogen and progesterone injectio
ns were observed on days 5 and 8 of pregnancy. These results strongly
suggest that estrogen regulates superoxide anion radical generation by
lowering the SOD activity.