Transvaginal absorption of estrogens through irradiated mucosa

Serum concentrations of unconjugated estrone (E1) and 17 beta-estradiol (E2) have been measured in eight patients before and after 1.25 mg of conjugated estrogens administered intravaginally. The measurements were repeated using 2 mg of micronized estradiol administered intravaginally 1 week later to six of the women and 7 months later in one. All the patients had completed a full course of irradiation for pelvic malignancy at least 8 months prior to the study. Baseline, 1/2, 1-, 2-, 4-, 8-, and 24-hr samples were analyzed. After conjugated estrogens mean serum E2 increased 4.5-fold to peak at 163 pg/ml at 2 hr while serum E1 increased 3.2-fold to peak at 222 pg/ml at 2 hr. After micronized E2 mean serum E2 increased 89.3-fold to peak at 1250 pg/ml at 1 hr while E1 increased 3.1-fold to peak at 416 pg/ml at 2 hr. These data indicate that rapid absorption of E1 and E2 occurs through irradiated vaginal mucosa.