Effect of estriol administration on the hypogonadal woman

To study the biologic effects of estriol, 14 hypogonadal patients received either vaginal or oral estriol. The vaginal administration of 0.5 mg of estriol to five patients resulted in increases of serum unconjugated and conjugated estriol levels which were maximal at 1 and 2 hours following treatment (161 ± 59 [SE] pg/ml and 762 ± 146 pg/ml, respectively). Significant suppression of luteinizing hormone (LH) to 84% and 81% of base line levels was observed at 2 and 3 hours following treatment, respectively (P Estriol is a weak estrogen. Rapid conjugation of the orally administered estriol renders it a weakly potent estrogen. Estriol administered vaginally is conjugated less rapidly than orally administered estriol, thus rendering it more biologically potent.