Plasma concentrations of unconjugated and conjugated estrogens and gonadotrophins following application of various estrogen preparations after oophorectomy and in the menopause

Assessment of estrogen exposure from transdermal estradiol gel therapy with a dried urine assay

Transdermal estradiol gel is a commonly used menopausal hormone therapy. In research studies investigating the pharmacokinetics and clinical utility of transdermal estradiol gels, serum is often used to measure estradiol levels. Serum results only represent a moment in time during phlebotomy and thus provide little information and allow for limited inference unless serial measurements are performed. In contrast, dried urine may provide a representation of serum estradiol levels over a longer period of time, while also being non-invasive and easier to collect. The primary aim of this study was to evaluate a dried urine method to determine if it may be a viable option for evaluating estrogen exposure resulting from transdermal estradiol gel use. A secondary aim was to explore differences in the urinary estrogen profiles of premenopausal women on no therapy and postmenopausal women who were either on transdermal estradiol gel therapy or no therapy at all. The results of this study demonstrated that the expected dose-proportional changes in estrogen exposure can be observed in the urinary estrogen profile using a GC-MS/MS dried urine assay. The GC-MS/MS assay also showed the differences in the urinary estrogen profiles of premenopausal women, postmenopausal women on estrogen replacement therapy, and postmenopausal women on no therapy.

Genistein Prevents BRCA1 CpG Methylation and Proliferation in Human Breast Cancer Cells with Activated Aromatic Hydrocarbon Receptor

Background: Previous studies have suggested a causative role for agonists of the aromatic hydrocarbon receptor (AhR) in the etiology of breast cancer 1, early-onset (BRCA-1)-silenced breast tumors, for which prospects for treatment remain poor. Objectives: We investigated the regulation of BRCA1 by the soy isoflavone genistein (GEN) in human estrogen receptor α (ERα)-positive Michigan Cancer Foundation-7 (MCF-7) and ERα-negative sporadic University of Arizona Cell Culture-3199 (UACC-3199) breast cancer cells, respectively, with inducible and constitutively active AhR. Methods: In MCF-7 cells, we analyzed the dose- and time-dependent effects of GEN and (-)-epigallocatechin-3-gallate (EGCG) control, selected as prototype dietary DNA methyltransferase (DNMT) inhibitors, on BRCA-1 expression after AhR activation with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and in TCDD-washout experiments. We compared the effects of GEN and EGCG on BRCA1 cytosine-phosphate-guanine (CpG) methylation and cell proliferation. Controls for DNA methylation and proliferation were changes in expression of DNMT-1, cyclin D1, and p53, respectively. In UACC-3199 cells, we compared the effects of GEN and α-naphthoflavone (αNF; 7,8-benzoflavone), a synthetic flavone and AhR antagonist, on BRCA1 expression and CpG methylation, cyclin D1, and cell growth. Finally, we examined the effects of GEN and αNF on BRCA1, AhR-inducible cytochrome P450 (CYP)-1A1 (CYP1A1) and CYP1B1, and AhR mRNA expression. Results: In MCF-7 cells, GEN exerted dose- and time-dependent preventative effects against TCDD-dependent downregulation of BRCA-1. After TCDD washout, GEN rescued BRCA-1 protein expression while reducing DNMT-1 and cyclin D1. GEN and EGCG reduced BRCA1 CpG methylation and cell proliferation associated with increased p53. In UACC-3199 cells, GEN reduced BRCA1 and estrogen receptor-1 (ESR1) CpG methylation, cyclin D1, and cell growth while inducing BRCA-1 and CYP1A1. Conclusions: Results suggest preventative effects for GEN and EGCG against BRCA1 CpG methylation and downregulation in ERα-positive breast cancer cells with activated AhR. GEN and flavone antagonists of AhR may be useful for reactivation of BRCA1 and ERα via CpG demethylation in ERα-negative breast cancer cells harboring constitutively active AhR.

Transdermal patches: history, development and pharmacology

Transdermal patches are now widely used as cosmetic, topical and transdermal delivery systems. These patches represent a key outcome from the growth in skin science, technology and expertise developed through trial and error, clinical observation and evidence-based studies that date back to the first existing human records. This review begins with the earliest topical therapies and traces topical delivery to the present-day transdermal patches, describing along the way the initial trials, devices and drug delivery systems that underpin current transdermal patches and their actives. This is followed by consideration of the evolution in the various patch designs and their limitations as well as requirements for actives to be used for transdermal delivery. The properties of and issues associated with the use of currently marketed products, such as variability, safety and regulatory aspects, are then described. The review concludes by examining future prospects for transdermal patches and drug delivery systems, such as the combination of active delivery systems with patches, minimally invasive microneedle patches and cutaneous solutions, including metered-dose systems.

Pharmacokinetics and biotransformation of orally administered oestrone sulphate and oestradiol valerate in post-menopausal women

The pharmacokinetic properties and biotransformation of two orally active oestrogens, piperazine oestrone sulphate (PE1S, 2.5 mg/day) and oestradiol valerate (E2V, 2.0 mg/day), given alone or in combination with levonorgestrel (LNG, 250 micrograms/day) were compared in 8 post-menopausal women, using a randomized cross-over design. The end points measured in peripheral plasma included oestrone (E1), oestradiol (E2), oestriol (E3), oestrone sulphate (E1S), oestradiol sulphate (E2S) and oestriol sulphate (E3S). In addition, LNG and sex-hormone-binding globulin SHBG concentrations were also assessed. The plasma levels of E3 were invariably below the detection limit (220 pmol/l). The levels of all the other oestrogens analyzed were consistently higher and the area under the curve significantly greater (except in the case of E3S) following PE1S administration than those recorded after E2V ingestion. The terminal half-lives of the circulating oestrogens measured after PE1S administration did not differ from those found after E2V administration. After 21 days of PE1S administration (in combination with LNG for the last 10 days), the maximum levels of all the oestrogens (except those of E2) were significantly higher than those seen after the first dose. No such difference was observed after E2V administration. There was no difference between the effects of the two treatment regimens with regard to the E1/E2 ratios, but the E1/E1S ratios were significantly lower after PE1S treatment than after E2V administration. It is concluded that, compared with an equivalent dose of PE1S, daily repeated oral administration of E2V yields consistently lower peripheral plasma levels of E2 and its principal metabolites. However, in contrast to PE1S therapy, prolonged administration of E2V does not result in an accumulation of the circulating oestrogens measured.

Effect of orally administered oestrogens on circulating oestrogen profiles in post-menopausal women

The effect of 4 peroral oestrogen regimens without and with levonorgestrel (LNG) supplementation (250 micrograms/day) was studied in 7 post-menopausal women. The regimens were: A: 2.5 mg piperazine oestrone sulphate/day; B: 1.25 mg piperazine oestrone sulphate + 5.0 mg oestriol/day; C: 2.0 mg oestradiol valerate/day and D: 10.0 mg oestriol/day. A randomized complete cross-over design was employed and systemic blood levels of progesterone (P), oestrone (E1), oestradiol (E2), oestriol (E3), oestrone sulphate (E1S), oestradiol sulphate (E2S) and oestriol sulphate (E3S) were analyzed. All subjects were consistently post-menopausal, as indicated by low P, E2, E1S and E3S and high FSH and LH levels. The pretreatment and post-treatment levels of E2 and E2S as well as those of E3 and E3S were invariably below detection limit (60 pmol/l and 220 pmol/l, respectively). Treatment with regimens A, B and C resulted in consistently detectable levels of E2, E2S and E3S, but not of E3, and in grossly elevated E1 and E1S levels. Treatment with regimen D gave rise to very high E3S levels. The oestrogen profiles produced by regimens A and C were almost identical, with the exception of higher E1 and lower E3S levels following the administration of regimen A. Combination with LNG did not modify the levels of unconjugated oestrogens, but in certain cases it seemed to diminish those of oestrogen sulphates. A comparison with the results of a preceding study (Aedo A-R et al., Effect of orally administered oestrogens on gonadotrophins levels in post-menopausal women. Maturitas 1989; 11:) reveals that the gonadotrophin-suppressing effect of all 4 regimens still persisted in the post-treatment period at a time when the levels of all oestrogens analyzed returned to those of the pretreatment period.

A review of study findings of the risks and benefits of oestrogen therapy in the female climacteric

A literature review was conducted to assess the evidence regarding the risks and benefits of oestrogen therapy in climacteric women. Consideration was given to the route of administration, effects on lipid levels, the skin and urinary symptoms, endometrial cancer, mortality and replacement therapy. It was concluded from the data examined that properly administered oestrogen treatment does not increase the risk of endometrial cancer and that the relative risk of death in oestrogen users aged over 40 is markedly lower than than in non-users.

Comparison of a triphasic oestradiol/norethisterone acetate preparation with and without an oestriol component in the treatment of climacteric complaints

This study was undertaken to evaluate the effects of oestriol in combination with oestradiol in the treatment of women with climacteric complaints. Forty-three post-menopausal women were randomly allocated to two groups on a double-blind basis. Over a 28-day cycle 23 of the women were treated sequentially for 12 days with 1 tablet containing 17 beta-oestradiol 2 mg plus oestriol 1 mg, then for 10 days with 1 tablet containing the same oestrogens plus norethisterone acetate 1 mg, thereafter for 6 days with 1 tablet containing 17 beta-oestradiol 1 mg plus oestriol 0.5 mg. The other 20 women received the same treatment but without the oestriol. No clinical, laboratory or histological differences were seen between the two groups. Both treatments were found to be equally effective in alleviating climacteric symptoms, with few side effects. It may be stated in conclusion that, on the basis of routine clinical and laboratory parameters no differences were found between the two preparations.

Absorption of an oestrogen-progestogen preparation

The plasma levels of oestradiol (E2), oestrone (E1), and norethisterone were studied in 6 post-menopausal women over a period of 24 h following the ingestion of a single, combined tablet containing 2 mg 17 beta-oestradiol, 1 mg oestradiol and 1 mg norethisterone acetate. The steroids were all in a nonesterified microcrystalline form. Three different batches of the preparation were used in the study; one was freshly prepared and the other two had been stored for 1 and 2 yr, respectively. The plasma oestradiol concentration increased rapidly, reaching a maximum level within 2 h, and then decreased gradually. After 24 h the basal value had not been regained. Oestrone levels followed approximately the same pattern. The E2-to-E1 ratio was high during the first 30 min after ingestion and then decreased to about 0.5. It remained more or less constant at this value, with a slight increase towards the end of the 24-h period. The norethisterone level rose and fell more rapidly. After about 8 h the level was practically down to zero.

Effects of a continuous estrogen-progestogen therapy for climacteric symptoms on circulating sex steroids and gonadotrophins

Twenty-six peri- and postmenopausal women with climacteric symptoms were given each day for 1 year a tablet containing 2 mg 17-beta-estradiol, 1 mg estriol and 1 mg norethisterone acetate. Blood samples were collected before, after 3 months and after 12 months of treatment and were analysed for their gonadotrophins, estradiol, estrone, testosterone, androstenedione content and for their SHBG binding capacity. Serum levels of estrone and androstenedione before treatment were found to be higher in the perimenopausal than in the postmenopausal group. An increase of serum estrogens concomitant with a decrease of gonadotrophins was noted. The estrone/estradiol ratios after 3 and 12 months of treatment were 5.3 and 4.7, respectively. A decrease in the serum concentration of testosterone and androstenedione was recorded during treatment. The reduction of gonadotrophins, especially LH, might have been responsible for the reduction in circulating androgens. The reduction of serum levels of androgens during the present long-term replacement therapy could be of metabolic importance.

Pharmacology of conjugated oestrogens

Conjugated equine oestrogens (CEE) as in Premarin have been used for the treatment of climacteric complaints and the prevention of oestrogen deficiency symptoms since the early 1940's. The biological activity of Premarin's different components is described. Our knowledge of the pharmacokinetics of the nine structurally related oestrogen conjugates in CEE is reviewed. Particular attention is paid to the significance of the sulphate moiety. It is possible that the sulphate group is exerting a 'protective' effect against sudden oestrogenic stimulation.

Serum concentrations of oestrone, oestradiol and oestriol during various oestrogen treatments

Serum oestradiol/oestrone ratios were measured during various oestrogen treatments in castrated women. Oral oestriol succinate therapy (8 mg/day) caused little change in the pre-treatment oestradiol/oestrone ratio. During oestradiol valerianate therapy (2 mg/day) serum total oestrogens and the E2/I1 ratio were considerably increased. One day after the injection of 10 mg of oestradiol valerianate and 2.5 mg of oestradiol benzoate + 10 mg of oestradiol phenylpropionate the E2/E1 ratio was similar to the ratio in middle of the normal ovulatory cycle. The change in serum oestriol was rather small after oral doses of 8 mg og oestriol succinate 15, 30 and 120 min after the application.

Oestrogens, gonadotropins and prolactin after intra-vaginal administration of oestriol in post-menopausal women

Serum total oestrone, 17 beta-oestradiol and oestriol concentrations and FSH, LH and prolactin values were measured radioimmunologically in post-menopausal women before and after intra-vaginal application of 0.5 mg oestriol. While oestrone and oestradiol were not altered, there was a 3100% increase in the mean oestriol values within 1 or 2 h; pre-treatment levels were again reached 8 h later. Both gonadotropins were moderately decreased, the serum prolactin values appeared to be slightly elevated. Repeated intra-vaginal application of oestriol resulted in a significant rise of the mean serum oestriol levels while the other oestrogens remained unchanged. The same was true for FSH and LH, a considerable negative feedback was therefore excluded. Again there seemed to be a slight rise of the prolactin secretion. It was concluded that intra-vaginal administration of oestriol is a most suitable local and systemic oestrogen replacement therapy, which is more effective than the oral regimen.

Serum oestrone, oestradiol and oestriol concentrations in castrated women during intramuscular oestradiol valerate and oestradiolbenzoate-oestradiolphenylpropionate therapy

Serum oestrone, oestradiol and oestriol concentrations were studied during intramuscular Primogyn Depot (10 mg of oestradiolvalerate) and Dimenformon prolongatum (2.5 mg of oestradiolbenzoate + 10 mg of oestradiolphenylpropionate) treatments. The serum oestrone concentrations were markedly elevated in both therapeutic groups 24 h after the injection. After the Primogyn Depot injection the serum oestrone concentration 10 days after the injection was still significantly higher than the pretreatment level. The serum oestradiol concentrations of both groups were markedly elevated 24 h after the injections and were significantly higher than the pretreatment concentration 10 days later. The oestriol values were low during both treatments.