17-beta-estradiol affects brain protein synthesis rate in ovariectomized female rats

The purpose of this study was to determine whether 17-beta -estradiol affec ts the rate of brain protein synthesis in ovariectomized female rats. Exper iments were conducted on three groups of 12-wk-old female rats: group 1 wer e ovariectomized to reduce the level of plasma estradiol, group 2 were ovar iectomized and treated with estradiol and group 3 were sham-operated contro ls. The fractional rates of protein synthesis in brain of ovariectomized ra ts treated with estradiol were significantly greater than that in ovariecto mized rats without estradiol treatment. In the cerebral cortex and cerebell um, the RNA activity [g protein synthesized/(g RNA . d)] significantly corr elated (r > 0.87, P < 0.001) with the fractional rate of protein synthesis. The RNA concentration (mg RNA/g protein) was not related to the fractional rate of protein synthesis in any organ. The results suggest that estrogen treatment of ovariectomized female rats is likely to increase the rate of p rotein synthesis in the brain and that RNA activity is at least in part rel ated to the fractional rate of brain protein synthesis.