Positive and negative effects of estradiol-17β in the rat uterus

Estrogens could act as effectors or inhibitors of protein synthesis in the rat uterus, depending on the doses given to animals. A single injection of estradiol-17β to immature female rats led to the increase in protein synthesis and in enzyme activities involved in DNA synthesis. Four injections, given once daily, resulted in the inhibition of enzyme activity and synthesis of all proteins but one. The 105 kD protein which showed a gradual increase with the duration of estrogen treatment could be responsible for the negative action of estiogens on uterine growth.