Comparative effectiveness of estrogens on fluid imbibition and growth of the rat's uterus.

TLDR: It was found that the minimal dose in micrograms required to produce 33⅓% increase in uterine wet weight at six hours (Astwood unit) is for estradiol, 0.025, and some estrogens are more effective for fluid imbibition and others more active for growth and superiority for one does not imply superiority for the other.

Abstract: Five natural estrogens (estradiol-17B, estrone, estriol, equilin and equilenin) and one synthetic estrogen (diethylstilbestrol) were compared as to effectiveness in promoting fluid imbibition and growth of the uterus in 22-day old rats. Graded amounts of each estrogen were injected subcutaneously as a single dose in 0.1 cc. sesameoil and uterine responses observed at intervals up to 72 hours. Both quantitative and qualitative differences were found with respect to dose required for a response and speed, duration, and extent of the reaction. Some estrogens are more effective for fluid imbibition and others more active for growth and superiority for one does not imply superiority for the other. It was found that the minimal dose in micrograms required to produce 33⅓% increase in uterine wet weight at six hours (Astwood unit) is for estradiol, 0.025; estriol, 0.029; diethylstilbestrol, 0.078; equilin, 0.312; estrone, 0.45; and equilenin, 0.546.The dosage required to produce 70% gain in uterine wet weight at ...