三苯氧胺合并米非司酮对大鼠抗早孕作用的研究

Effects of Tamoxifen Combined with Mifepristone on Early Pregnancy in Rat.

用大鼠进行抗早孕实验,观察三苯氧胺(TMX)与米非司酮合并用药的抗早孕作用。大鼠于妊娠d7,ig4.0mg·kg^(-1)TMX,连续3天,流产率为62.5％,加用1.0mg·kg^(-1)米非司酮后流产率为87.5％,加用4.0mg·kg^(-1)米非司酮后流产率为37.5％,给药后测定孕鼠血清孕酮水平,4.0mg·kg^(-1)米非司酮组d10和d14,4.0mg·kg^(-1)TMX组d14,1.0mg·kg^(-1)米非司酮+4.0mg·kg^(-1)TMX组d14孕酮均明显降低;4.0mg·kg^(-1)米非司酮+4.0mg·kg^(-1)TMX组d10孕酮降低,d14孕酮反而升高。结果表明:米非司酮不影响TMX的雌激素和抗雌激素活性;TMX和小剂量米非司酮合用抗早孕有协同作用;TMX与大剂量米非司酮对抗早孕有拮抗作用。

Treatment with tamoxifen at the dose of 4mg·kg-1 on day 7 - 9 of gestation had significant effect on terminating early pregnancy in rat. Tamoxifen combined with a non-effective dose of 1. 0mg · kg-1 mifepristone was shown to have a synergistic effect on terminating early pregnancy. Tamoxifen combined with an effective dose of 4. 0mg · kg-1 mifepristone was shown to have significantly decreased effect on terminating early pregnancy. 1. 0mg · kg-1 mifepristone + 4. 0mg · kg-1 tamox-ifen on day 7-9 of gestation significantly decreased the concentration of serum progesterone to low level on day 14 of pregnancy. 4.0mg·kg-1mifepristone + 4.0mg · kg-1tamoixfen on day 7-9 of gestation significantly decreased the concentration of serum progesterone on day 10,but significantly increased it to high level on day 14. Further study demonstrated that tamoxifen increased uterine weight in the immature rat and mifepristone did not have effect on the actions of tamoxifen in the uterine weight assay. These results suggested that there existed Synergism of tamoxifen combined with a small dose of mifepristone on terminating early pregnancy, and existed counteraction when tamoxifen combined with a high dose of mifepristone.