INHIBITION OF HUMAN PLACENTAL PROGESTERONE SYNTHESIS BY DANAZOL INVIVO

In vivo, a single dose of 1000 mg danazol was given orally to 8 pregnant volunteers prior to a therapeutic abortion (8th-12th wk of gestation). Changes in serum progesterone and estradiol were evaluated by analysis of percentage values related to initial concentrations. Following treatment a significant decrease in mean plasma progesterone of .apprx. 20% was observed within 2-4 h; progesterone levels varied between 80-120% during 24 h in controls (n = 10); individual serum estradiol decreased up to 30% of control values 2 h after danazol application. Changes in estradiol in controls vs. tests were not statistically significant (P < 0.05) when absolute estradiol concentrations were compared. Only a slight (10-20%) decrease in mean serum DHAS was found 2-6 h following danazol treatment. The inhibitory activity of danazol on human maternal and fetal steroidogenesis in vivo is thus demonstrated. The possible sites of action of danazol are discussed.