Estrogen replacement in ovariectomized rats results in physiologically significant levels of circulating progesterone, and co-administration of progesterone markedly reduces the circulating estrogen.
Estrogen replacement in ovariectomized rats results in physiologically significant levels of circulating progesterone, and co-administration of progesterone markedly reduces the circulating estrogen.
复制标题
卵巢切除大鼠的雌激素替代导致循环孕酮的生理显着水平，并且孕酮的共同施用显着降低循环雌激素。
作者：
Liu,JW;Dawson,DD;Peters,CE;Baker,MA;Walker,AM
Estrogen or progesterone replacement in ovariectomized rats is an often-used experimental system for determination of the specific effects of these hormones. In this study, two different delivery systems and two different dosage levels of estrogen, progesterone or a combination of the two have been used. Estrogen and progesterone in the circulation have been measured in response to each treatment. It is reported that estrogen treatment (237.2±49.2 pg/mL) results in physiologically significant levels of circulating progesterone (11.1±1.3 ng/mL). Also, co-administration of progesterone (23.7±2.0 ng/mL) with estrogen decreases the level of estrogen over that seen with estrogen alone (96.7±19.2 pg/mL with progesterone vs 237.2±49.2 pg/mL without progesterone). Thus, contrary to expectations, estrogen replacement therapy is not specific to estrogen and some of the antagonistic effects of progesterone are the result of a decrease in circulating estrogen, and not a specific effect on a target tissue. Whereas the mechanism of these effects has not been determined, obvious artifactitious phenomena have been excluded as being their cause. These results could have a major impact on the interpretation of past and future experiments of this kind.
