Half-Life of Estradiol in Postmenopausal Women

Abstract

Estrogen replacement is often advised for postmenopausal women to prevent menopausal symptoms, osteoporosis and heart disease. However, little information is available concerning the half-life of estradiol (E₂) in postmenopausal women. This study was designed to determine the half-life and metabolism of transdermal E₂. A prospective clinical study of 8 healthy postmenopausal women was performed in the Clinical Research Center of the Brigham and Women’s Hospital. A transdermal E₂ patch 0.10 mg was placed on the abdominal wall. Thirteen hours later, after an overnight fast, the E₂ patch was removed and frequent blood sampling was performed over 6 h. Serum samples were assayed for E₂, estrone (E₁) and estrone sulfate (E₁S). Serum samples were taken before E₂ patch placement, for 30 min before patch removal, and for 6 h after patch removal. The basal E₂ level of women prior to use of transdermal E₂ was 19 ± 2 pg/ml (mean ± SE). Thirteen hours after transdermal E₂ placement, steady state levels had been reached, with a mean E₂ of 112 ± 6 pg/ml. The mean half-life of E₂ after removal of transdermal E₂ was 161 min (range 107–221 min). There was a direct relationship between the subjects’ weight and the half-life of E₂ (r = 0.79, p = 0.02). Mean basal E₁ levels were 23 ± 5 pg/ml and mean E₁ steady-state levels after E₂ patch placement were 39 ± 0.6 pg/ml. E₁S levels rose from mean basal levels of 1.5 ± 0.3 ng/ml to mean steady-state levels of 3.1 ± 0.1 ng/ml after placement of the E₂ patch. The apparent half-life of E₂ after discontinuing a transdermal E₂ patch is 2.7 h or 161 min.

Circulating sex hormones and breast cancer risk factors in postmenopausal women: reanalysis of 13 studies

“…As the half-life of oestradiol is ∼3 h (Ginsburg et al , 1998), it is possible that there is a marked increase of oestradiol shortly after alcohol consumption in the evening, which cannot be assessed in typical epidemiological studies. In a study of the acute effects of 40 g of alcohol in premenopausal women, circulating oestradiol concentrations increased and reached a peak 25 min after alcohol ingestion (Mendelson et al , 1988).…”

The Role of Skeletal Muscle in Maintaining Vitamin D Status in Winter

“…Thus, the blood circulation has also been assumed to be the storage site of vitamin D, particularly because the residence time half-life of 25(OH)D ranges from 15 to 60 d (18) and perhaps even as long as 120 d (19). This is far longer than a typical steroid in blood such as estradiol, with a half-life of only 2–3 d (20), or indeed of the endocrine product of vitamin D, 1,25(OH) 2 D, with a half-life of only 5–8 h (21, 22)…”

Alcohol and oestrogen metabolites in postmenopausal women in the Women’s Health Initiative Observational Study

“…We evaluated usual (12-month) frequency of alcohol consumption, but were unable to compare acute versus chronic alcohol exposure, or alcohol exposure across the life course. We evaluated average weekly alcohol consumption, which may not be the relevant exposure to evaluate effects on oestrogen metabolism since the timing of last alcohol ingestion could influence oestrogen concentration due to the short half-life of oestrogens (Ginsburg et al , 1998). Women enrolled in the WHI-OS included a subset that declined participation in WHI trials, which could have introduced selection bias in terms of alcohol exposure, although participants of the WHI clinical trials (Jackson et al , 2003; Ritenbaugh et al , 2003; Stefanick et al , 2003) had a similar distribution of alcohol consumption to the observational study (Langer et al , 2003).…”