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.