Rate of hydrogen peroxide production using succinate as substrate of the mitochondrial respiratory chain in hepatic isolated mitochondria. Sham operated (Sham), ovariectomized for 3 weeks (OVX 3), ovariectomized for 6 weeks (OVX 6), ovariectomized for 9 weeks (OVX 9), OVX 3 and immediately replaced with estradiol (OVX 3E), OVX 3 and replaced with estradiol 3 weeks after ovariectomy (OVX 3+3E), ovariectomized for 6 weeks, and replaced with estradiol 6 weeks after ovariectomy (OVX 6+3E). Data are expressed as mean±SD of five to eight different experiments. The statistical significance is expressed as *p<0.05 versus control; **p<0.01 versus control; ***p<0.001 versus control; #p<0.05 versus OVX 3. N.S., nonsignificant differences between groups.