Uptake, accumulation, and translocation mechanisms of steroid estrogens in plants

Applying sewage sludge or animal manure onto agricultural land can result in estrogen pollution, which increases the risk of human exposure to steroid estrogens (SEs) via the food chain. However, the uptake and accumulation mechanism of SEs by plants is still unclear. In this study, the uptake, accumulation, and translocation of 17β-E2, a representative SE, were investigated through a series of wheat hydroponic experiments. Various inhibitors were applied to explore the uptake pathways of 17β-E2 by wheat. In addition, the effects of exposure concentrations, coexisting 17α-ethynylestradiol (EE2) and plant properties on the uptake of 17β-E2 were examined. The results indicated that the accumulation of 17β-E2 in wheat roots mainly resulted from adsorption and active uptake that involved aquaporins and anion channels transport. The chlorophyll and protein contents of plants were positively correlated with the uptake of 17β-E2, whereas competitive inhibition occurred when 17β-E2 and EE2 coexisted in the same solution. Nevertheless, the results of a split-root experiment showed that 17β-E2 absorbed by wheat could further migrate in plant via long-distance transport and ultimately was discharged from plants, suggesting that 17β-E2 was still at risk of being released even though it had been absorbed by plants. These results could provide valuable insights into the risk assessment and risk control of the uptake of SEs by plants.

In vivo profiling of 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced estrogenic/anti-estrogenic effects in female estrogen-responsive reporter transgenic mice

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), commonly referred to simply as "dioxin", is a persistent environmental pollutant. Because of its high environmental persistence and biological accumulation, humans and animals are often exposed to TCDD. Therefore, the harmful effects on humans and animals is a major concern. Although studies have elucidated the adverse estrogenic and anti-estrogenic effects of TCDD, it is unclear in which tissues TCDD exerts these effects in vivo. To investigate the estrogen-related effects of TCDD in various tissues, we generated an improved estrogen-responsive reporter transgenic mouse in which the luciferase gene luc2 is expressed in response to estrogenic signals. Using these mice, we clarified that TCDD inhibits estrogenic signaling in liver and kidney but enhances estrogenic signaling in the pituitary gland in the same individual. Expression of aryl hydrocarbon receptor, aryl hydrocarbon receptor nuclear translocator, and estrogen receptor alpha mRNA was detected in liver, kidney, and pituitary gland, suggesting that the effects of TCDD on estrogenic signaling in these organs is independent of the expression pattern of these receptors. Thus, our results indicate that TCDD exerts both estrogenic and anti-estrogenic tissue-specific effects within the same individual.

Transgender women on oral HIV pre-exposure prophylaxis have significantly lower tenofovir and emtricitabine concentrations when also taking oestrogen when compared to cisgender men

INTRODUCTION

Oral HIV Pre-Exposure Prophylaxis (PrEP) with tenofovir (TFV) disoproxil fumarate (TDF)/emtricitabine (FTC) is highly effective. Transgender women (TGW) have increased HIV risk, but have been underrepresented in trials. For TGW on oestrogens for gender-affirming hormone treatment (GAHT), TDF/FTC-oestrogen interactions may negatively affect HIV prevention or gender-affirming goals. Our aim was to evaluate any pharmacokinetic drug-drug interaction between GAHT and TDF/FTC.

METHODS

We performed a pharmacokinetic study, in an urban outpatient setting in 2016 to 2018, of the effects of GAHT on TFV, FTC and the active forms TFV diphosphate (TFV-DP) and FTC triphosphate (FTC-TP) in eight TGW and eight cisgender men (CGM). At screening, participants were HIV negative. TGW were to maintain their GAHT regimens and have plasma oestradiol concentrations >100 pg/mL. Under direct observation, participants took oral TDF/FTC daily for seven days. At the last dose, blood was collected pre-dose, one, two, four, six, eight and twenty-four hours, and colon biopsies were collected at 24 hours to measure drug concentration. TGW versus CGM concentration comparisons used non-parametric tests. Blood and colon tissue were also obtained to assess kinase expression.

RESULTS

Plasma TFV and FTC C24 (trough) concentrations in TGW were lower by 32% (p = 0.010) and 32% (p = 0.038) respectively, when compared to CGM. Plasma TFV and FTC 24-hr area under the concentration-time curve in TGW trended toward and was significantly lower by 27% (p = 0.065) and 24% (p = 0.028) respectively. Peak plasma TFV and FTC concentrations, as well as all other pharmacokinetic measures, were not statistically significant when comparing TGW to CGM. Oestradiol concentrations were not different comparing before and after TDF/FTC dosing. Plasma oestrogen concentration, renal function (estimated creatinine clearance and glomerular filtration rate), and TFV and FTC plasma concentrations (trough and area under the concentration-time curve) were all correlated.

CONCLUSIONS

GAHT modestly reduces both TFV and FTC plasma concentrations. In TGW taking GAHT, it is unknown if this reduction will impact the HIV protective efficacy of a daily PrEP regimen. However, the combination of an on demand (2 + 1 + 1) PrEP regimen and GAHT may result in concentrations too low for reliable prevention of HIV infection.

Prospects of and limitations to the clinical applications of genistein

Genistein is an isoflavone derived from soy-rich products, which is known to exhibit several beneficial biological effects, such as anti-tumor activity, improvement of glucose metabolism, and reduction of the frequency of peri-menopausal hot flashes, and thus has potential for clinical application. Certain limitations and side effects, such as low bioavailability, biological estrogenic activity, and detrimental effects on thyroid function, have restricted its clinical applications to some extent. Recently, it has been reported that fermentation, use of micromicelles, and modification of its chemical structure can enhance the bioavailability of genistein. Moreover, the modification of its molecular structure may also eliminate its biological estrogenic activity and adverse effects on thyroid function. In this review, we summarize the clinical application prospects and limitations of genistein, as well as the plausible solutions to overcome its low bioavailability, phytoestrogenic activity, and adverse effects on thyroid function.

In silico binding of 4,4'-bisphenols predicts in vitro estrogenic and antiandrogenic activity

Bisphenols, anthropogenic pollutants, leach from consumer products and have potential to be ingested and are excreted in waste. The endocrine disrupting effects of highly manufactured bisphenols (BPA, BPS, and BPF) are known, however the activities of others are not. Here, the estrogenic and androgenic activities of a series of 4,4'-bisphenols that vary at the inter-connecting bisphenol bridge were determined (BPA, BPB, BPBP, BPC2, BPE, BPF, BPS, and BPZ) and compared to in silico binding to estrogen receptor-alpha and the androgen receptor. Bioassay results showed the order of estrogenicity (BPC2 (strongest) > BPBP > BPB > BPZ > BPE > BPF > BPA > BPS, r²  = 0.995) and anti-androgenicity (BPC2 (strongest) > BPE, BPB, BPA, BPF, and BPS, r²  = 0.996) correlated to nuclear receptor binding affinities. Like testosterone and the anti-androgen hydroxyflutamide, bisphenol fit in the ligand-binding domain through hydrogen-bonding at residues Thr877 and Asn705, but also interacted at either Cys784/Ser778 or Gln711 through the other phenol ring. This suggests the 4,4'-bisphenols, like hydroxyflutamide, are androgen receptor antagonists. Hydrogen-bond trends between ERα and the 4,4'-bisphenols were limited to residue Glu353, which interacted with the -OH of one phenol and the -OH of the A ring of 17β-estradiol; hydrogen-bonding varied at the -OH of ring D of 17β-estradiol and the second phenol -OH group. While both estrogen and androgen bioassays correlated to in silico results, conservation of hydrogen-bonding residues in the androgen receptor provides a convincing picture of direct antagonist binding by 4,4'-bisphenols.

The sexuological impact of hormonal contraceptives based on their route of administration

Evidence on the effects of hormonal contraceptives on female sexuality is conflicting. We enrolled 556 women, divided into six groups: two composed of subjects using a combined hormonal contraceptive (COC) containing 0.020 ("COC20") and 0.030 ("COC30") mg of ethynyl estradiol (EE), "natural", using COC containing 1.5 mg of estradiol (E₂), "ring", using a vaginal ring releasing each day 0.015 mg of EE + 0.120 of etonogestrel, "subcutaneous", using a progestin only subcutaneous contraceptive implant releasing etonogestrel and "controls", using no hormonal contraceptive methods. The subjects were required to answer to the McCoy female sexuality questionnaire and were subjected to a blood test for hormonal evaluation. An ultrasound evaluation of the dorsal clitoral artery was also performed. The higher McCoy sexological value were recorded in the subdermal group; significant differences were recorded among the groups in terms of hormone distribution, with the higher levels of androstenedione in subdermal and control groups. The ultrasound evaluation of dorsal clitoral artery shows a significative correlation between pulsatility and resistance indices and orgasm parameters of McCoy questionnaire. The recorded difference in the sexual and hormonal parameters among the studied hormonal contraceptives may guide toward the personalization of contraceptive choice.

In vitro metabolism of methiocarb and carbaryl in rats, and its effect on their estrogenic and antiandrogenic activities

In this work, we examined the metabolism of the carbamate insecticides methiocarb and carbaryl by rat liver microsomes and plasma, and its effect on their endocrine-disrupting activities. Methiocarb and carbaryl were not enzymatically hydrolyzed by rat liver microsomes, but were hydrolyzed by rat plasma, mainly to methylthio-3,5-xylenol (MX) and 1-naphthol, respectively. When methiocarb was incubated with rat liver microsomes in the presence of NADPH, methiocarb sulfoxide was formed. The hydrolysis product, MX, was also oxidized to the sulfoxide, 3,5-dimethyl-4-(methylsulfinyl)phenol (SP), by rat liver microsomes in the presence of NADPH. These oxidase activities were catalyzed by cytochrome P450 and flavin-containing monooxygenase. Methiocarb and carbaryl both exhibited estrogen receptor α (ERα) and ERβ agonistic activity. MX and 1-naphthol showed similar activities, but methiocarb sulfoxide and SP showed markedly decreased activities. On the other hand, methiocarb and carbaryl exhibited potent antiandrogenic activity in the concentration range of 1×10(-6)-3×10(-5) M. Their hydrolysis products, MX, and 1-naphthol also showed high activity, equivalent to that of flutamide. However, methiocarb sulfoxide and SP showed relatively low activity. Thus, hydrolysis of methiocarb and carbaryl and oxidation of methiocarb to the sulfoxide markedly modified the estrogenic and antiandrogenic activities of methiocarb and carbaryl.

Serum estradiol level during withdrawal bleeding as a predictive factor for intermittent ovarian function in women with primary ovarian insufficiency

The objective of this study was to assess the potential predictive factors for follicle growth, ovulation, and pregnancy rate in patients with primary ovarian insufficiency/premature ovarian failure (POI/POF). We enrolled 25 POI patients with desired fertility who were treated and monitored for a minimum of 7 months between the years of 2000-2009 into this retrospective study. The clinical, endocrinologic, chromosomal, and autoimmunologic parameters of these patients were collected. Furthermore, hormonal backgrounds on each of 620 treatment cycles were investigated. The main outcome measures were follicle growth, ovulation, and pregnancy rate. Four of 25 patients (16%) conceived while being monitored and undergoing treatment. Follicle growth, ovulation, and pregnancy rate were not significantly different as a function of parity, iatrogenic history (e.g., chemotherapy), age of disease onset, serum estradiol (E(2))/follicle stimulating hormone (FSH) level at the time of diagnosis, chromosomal abnormality, and positive autoantibody titer. The serum E2 levels on days 1-5 of withdrawal bleeding (Day 1-5 E(2)) were significantly higher in the cycles with successful follicle growth and ovulation than unsuccessful cycles (P<0.05). Receiver-operator characteristic curve analysis revealed the cut-off value of the Day 1-5 E(2) to be 15.5 pg/mL, and an area under the curve (AUC) value of 0.674 for follicle growth and 0.752 for ovulation. The results suggest that cycles with a Day 1-5 E(2)≥15.5 pg/mL have a higher rate of follicle growth and ovulation in patients with POI.

Transpapillary drug delivery to the breast

The study was aimed at investigating localized topical drug delivery to the breast via mammary papilla (nipple). 5-fluorouracil (5-FU) and estradiol (EST) were used as model hydrophilic and hydrophobic compounds respectively. Porcine and human nipple were used for in-vitro penetration studies. The removal of keratin plug enhanced the drug transport through the nipple. The drug penetration was significantly higher through the nipple compared to breast skin. The drug’s lipophilicity had a significant influence on drug penetration through nipple. The ducts in the nipple served as a major transport pathway to the underlying breast tissue. Results showed that porcine nipple could be a potential model for human nipple. The topical application of 5-FU on the rat nipple resulted in high drug concentration in the breast and minimal drug levels in plasma and other organs. Overall, the findings from this study demonstrate the feasibility of localized drug delivery to the breast through nipple.

Trenbolone acetate metabolite transport in rangelands and irrigated pasture: observations and conceptual approaches for agro-ecosystems

To assess the relative ecological risks of trenbolone acetate (TBA) use in agro-ecosystems, we evaluated the spatiotemporal dynamics of TBA metabolite transport during irrigation and rainfall events. Within a pasture, TBA-implanted heifers (40 mg TBA, 8 mg estradiol) were briefly penned (24 h) at high stocking densities (500 animal units (AU)/ha), prior to irrigation. Irrigation runoff concentrations of 17α-trenbolone (17α-TBOH) 0.3 m downslope were 11 ng/L in the wetting front, but quickly decreased to ∼0.5 ng/L, suggesting mass transfer limitations to transport. At 3 and 30 m downslope, efficient attenuation of 17α-TBOH concentrations is best explained by infiltration and surface partitioning. At plot scales, transport through vegetated filter strips resulted in <0.5-7 ng/L 17α-TBOH concentrations in rainfall-induced runoff with partial subsequent attenuation. Thus, even under intense grazing scenarios, TBA-metabolite transport potential is expected to be low in rangelands, with ecological risks primarily arising from uncontrolled animal access to receiving waters. However, 17α-TBOH concentrations in initial runoff were predicted to exceed threshold levels (i.e., no observed adverse effect levels [NOAELs]) for manure concentrations exceeding 2.0 ng/g-dw, which occurs throughout most of the implant life. For comparison, estrone and 17β-estradiol were modeled and are likely capable of exceeding NOAELs by a factor of ∼2-5 in irrigation runoff, suggesting that both endogenous and exogenous steroids contribute to endocrine disruption potential in agro-ecosystems.

Bisphenol A--sources, toxicity and biotransformation

Bisphenol A (BPA) is a chemical compound used in massive amounts in the production of synthetic polymers and thermal paper. In this review, the sources of BPA, which influence its occurrence in the environment and human surrounding will be presented. Data concerning BPA occurrence in food, water and indoor environments as well as its appearance in tissues and body fluids of human body will be shown. The results of in vitro and in vivo studies and the results of epidemiological surveys showing toxic, endocrine, mutagenic and cancerogenic action of BPA will also be discussed. Moreover, data suggesting that exposure of human to BPA may elevate risk of obesity, diabetes and coronary heart diseases will be presented. Finally, biotransformation of BPA in animals, plants and microorganisms (bacteria, fungi, algae), resulting in the formation of various metabolites that exhibit different from BPA toxicity will be described.

[Pharmacological, metabolic and clinical aspects of new oral contraceptive associations containing natural estrogens]

Introduction of new compounds containing natural estrogens represented a major development in the field of hormonal contraception. Micronized estradiol (E2) and its estere valerate (EV), is more easily metabolized by the liver than ethynylestradiol (EE). This causes minimal metabolic impact, but the weak estrogenic activity needs not be antagonized by androgenic progestin and requires progestin capable to stabilize the endometrium. Dienogest (DNG), an antiandrogenic progestin with a short half-life, is associated with estradiol valerate (EV) in a quadriphasic fashion. In comparison to EE/levonorgestrel (LNG), EV/DNG is more neutral on metabolism and coagulation. Furthermore, it does not seem to negatively affect the cardiovascular system and breast. Cycle control is optimal with a higher prevalence of amenorrhea and reduction of menstrual flow. For this reason EV/DNG can be tehrapeutic for heavy menstrual bleedings. Nomegestrol acetate (NOMAc), an anti-andogen progestin with a long half-life is combined in monophasic regimen with micronized E2. E2/NOMAc is more neutral than EE/LNG on metabolism and more neutral than EE/DRSP on coagulation. NOMAc reduces peripheral tissue estrogen formation, and this may be beneficial for the breast. The two formulations exert a high contraceptive efficacy similar to the ones containing EE, but with less estrogen-related side-effects. The additional benefits due to DNG and NOMAc need to be further explored.

Characterization of estrogen-receptor-targeted contrast agents in solution, breast cancer cells, and tumors in vivo

The estrogen receptor (ER) is a major prognostic biomarker of breast cancer, currently determined in surgical specimens by immunohistochemistry. Two new ER-targeted probes, pyridine-tetra-acetate-Gd chelate (PTA-Gd) conjugated either to 17β-estradiol (EPTA-Gd) or to tamoxifen (TPTA-Gd), were explored as contrast agents for molecular imaging of ER. In solution, both probes exhibited a micromolar ER binding affinity, fast water exchange rate (∼10(7) s(-1)), and water proton-relaxivity of 4.7-6.8 mM(-1) s(-1). In human breast cancer cells, both probes acted as estrogen agonists and enhanced the water protons T1 relaxation rate and relaxivity in ER-positive as compared to ER-negative cells, with EPTA-Gd showing a higher ER-specific relaxivity than TPTA-Gd. In studies of breast cancer tumors in vivo, EPTA-Gd induced the highest enhancement in ER-positive tumors as compared to ER-negative tumors and muscle tissue, enabling in vivo detection of ER. TPTA-Gd demonstrated the highest enhancement in muscle tissue indicating nonspecific interaction of this agent with muscle components. The extracellular contrast agents, PTA-Gd and GdDTPA, showed no difference in the perfusion capacity of ER-positive and -negative tumors confirming the specific interaction of EPTA-Gd with ER. These findings lay a basis for the molecular imaging of the ER using EPTA-Gd as a template for further developments.

Effect of estrogen and testosterone replacement therapy on cognitive fatigue

Both estrogen and testosterone insufficiency has been associated with reduced psychological well-being including fatigue. However, hormonal replacement studies on fatigue are rare. Therefore, we wanted to study the effect of testosterone and estrogen replacement therapy on cognitive fatigue and the relation between sex hormone levels and cognitive fatigue in oophorectomized women. Fifty women with surgically induced menopause (mean age: 54.0 ± 2.9 years) were randomly assigned to treatment with estradiol valerate in combination with testosterone undecanoate or placebo for 24 weeks in a double-blind cross-over study. Neuropsychological tests and questionnaires were used to assess cognitive fatigue and psychological well-being. Cognitive fatigue was significantly associated to poor self-rated health and higher body mass index but not to general psychological well-being or sex hormone levels. Treatment with testosterone + estrogen had no significant effect on cognitive fatigue but the results indicated a curvilinear relation for hormonal levels. The estrogen/testosterone ratio was more related to functions rather than high or low hormone levels per se. We found that cognitive fatigue is frequent in oophorectomized women and negatively associated to self-perceived health and positively associated to BMI. A well-balanced ratio between estrogen and testosterone levels may be important for cognitive fatigue.

Accumulation and pharmacokinetics of estrogenic chemicals in the pre- and post-hatch embryos of the frog Rana rugosa

Amphibian eggs spawned in water are exposed immediately to various chemicals present in their water. The present study aimed to investigate the accumulation and pharmacokinetics of 17α-ethynylestradiol (EE(2)), bisphenol A (BPA), and nonylphenol (NP), as well as 17β-estradiol (E(2)), in the pre-hatch and post-hatch embryos of the frog Rana rugosa. Fertilized eggs were exposed to chemicals at a final concentration of 500 nM in breeding water for two days, then the embryos with jelly coats were reared in fresh-breeding water without supplementation of the xenoestrogens for six more days. All exogenous chemicals were concentrated in the embryo body at two days after fertilization, whereas their concentrations in the jelly coat were the same as those in the breeding water. The bioconcentration factors for E(2), EE(2), BPA, and NP were 217.9, 170.2, 382.3, and 289.1, respectively, suggesting that the estrogenic chemicals were concentrated in the embryo body through the jelly coat.

Uptake of natural and synthetic estrogens by maize seedlings

Runoff from manure-fertilized crop fields constitutes a significant source of natural estrogens (e.g., estradiol [17β-E2] and estrone [E1]) and synthetic estrogen mimics (e.g., zeranol [α-ZAL] and zearalanone [ZAN]) in the environment. However, processes such as sorption to and uptake by plants may inhibit the environmental mobility of hormonally active compounds. Sorption to dried root tissue was assessed in batch sorption tests, and resulting sorption isotherms were nonlinear at aqueous concentrations below 0.1 μM and linear above that limit. To evaluate the role of crop plants in the environmental fate of such compounds, we exposed hydroponic solutions containing 2 μM 17β-E2, E1, α-ZAL, or ZAN to maize seedlings. After 22 days of exposure, α-ZAL and ZAN concentrations decreased by more than 96%, and 17β-E2 and E1 were undetectable. The decrease in α-ZAL and ZAN concentrations in maize-exposed solutions was initially slow, but the observed uptake exceeded that predicted by sorption alone within 3 d. All four estrogens were detected in root tissues at concentrations up to 0.19 μmol g(-1), with concentrations peaking after 1-3 days of exposure. Only 17β-E2 and α-ZAL were detected in shoots, and maximum concentrations were measured after 2 days for 17β-E2 (0.02 μmol g(-1)) and 16 days for α-ZAL (0.8 nmol g(-1)). Concentrations measured in root and shoot tissues were 82% or less than those predicted by a partition-limited uptake model, which is attributed to transformation and possibly irreversible binding processes.

Ablation of the ATP-binding cassette transporter, Abca2 modifies response to estrogen-based therapies

The ATP-binding cassette transporter 2 (ABCA2) is an endolysosomal protein expressed in oligodendrocytes and Schwann cells, prostate, ovary and macrophages. In cell cultures, ABCA2 over-expression has been linked with resistance to the anticancer agent, estramustine phosphate (EMP; a nor-nitrogen mustard conjugate of estradiol). The present study shows that Abca2 knockout (KO) mice have greater sensitivity to a variety of side effects induced by EMP treatment. Chronic EMP (12×100 mg/kg body weight) produced mortality in 36% of KO mice, but only 7% of age-matched wild type (WT). Side effects of the drug were also more prevalent in the KO mouse. For example, during the first week of EMP treatments, 67% of KO males (compared to 6% of WT males) responded with episodic erectile events. In WT mice, ABCA2 protein localized within pene corpuscles, (which rely on modified Schwann cells for amplification of tactile signals) suggesting that the transporter may function in the erectile process. Endothelial nitric oxide synthase (eNOS; a source of nitric oxide during erectile response) levels were similar in WT and KO male penile tissue. Treatment with 100 mg/kg EMP (once daily for four days) elevated serum estradiol and estrone in both WT and KO. However, the circulating levels of these estrogens were higher in KO mice implying a reduced plasma clearance of estrogens as a consequence of ABCA2 ablation. Consistent with the pro-convulsant effects of estrogens, KO mice also displayed an increased incidence of seizures following EMP (14% vs. 0%). Taken together, these data indicate that ABCA2 deficiency renders mice more sensitive to EMP treatment-induced effects implying that the transporter has a role in regulating EMP transport and/or metabolism.

Pharmacokinetics and ovarian suppression during use of a contraceptive vaginal ring in normal-weight and obese women

OBJECTIVE

Many observational studies indicate higher oral contraceptive failure among obese women, but most clinical trials and physiologic studies do not support these differences. Limited data indicate higher failure rates among obese contraceptive patch users. Data regarding contraceptive vaginal ring performance in obese women are needed.

STUDY DESIGN

Twenty normal weight (body mass index [BMI] 19.0-24.9; median, 21.65) and 20 obese (BMI 30.0-39.9; median, 33.7) women enrolled in a prospective study of ethinyl estradiol (EE(2)) and etonorgestrel pharmacokinetics and of ovarian follicle development, endometrial thickness, and bleeding patterns, all measured biweekly during the second cycle of contraceptive vaginal ring use.

RESULTS

Thirty-seven women completed follow-up. Mean day 0-21 EE(2) concentrations were lower among obese vs normal weight women (15.0 vs 22.0 pg/mL, respectively, P = .004), whereas etonorgestrel concentrations were similar (1138 vs 1256 pg/mL, respectively, P = .39). Follicular development was minimal in both groups, with only 5 women achieving a maximum follicle diameter >13 mm at any time during 3 weeks follow-up (3 normal weight and 2 obese women); these women had serum progesterone levels <1.0. Obese women reported more bleeding or spotting than normal weight women (3.6 vs 1.4 days, respectively, P = .01).

CONCLUSION

Although obese women had lower EE(2) levels during contraceptive vaginal ring use, they had excellent suppression of ovarian follicle development, similar to normal weight women. This predicts that contraceptive vaginal ring effectiveness will be similar in women with a BMI up to 39.9. The lower serum EE(2) levels in the obese women may explain the greater reported bleeding or spotting days.

Estrogen therapy in Turner syndrome: does the type, dose and mode of delivery matter?

The best type, dose and route of estrogen replacement in hypogonadal females has not been fully elucidated and is the subject of this brief review. When feminizing girls with different forms of hypogonadism micronized 17betaE2 should be considered the first choice as it is the most physiological and can be accurately measured in plasma. Most studies of the metabolic effects of the different routes have also used different types of estrogen making comparisons difficult. However, when using the same estradiol compound, 17betaE2 transdermal results in E2, E1 and bioestrogen concentrations closer to normal as compared to oral and achieves greater suppression of LH/FSH but similar IGF-I and lipid concentrations. Whether this translates into better body composition and metabolic outcomes in girls with hypogonadism is being actively investigated and data will soon be available.

Cocktail effects on biomarker responses in fish

One of today's greatest challenges in environmental toxicology is to understand effects of mixture toxicity, commonly referred to as cocktail effects, in humans and in wildlife. Biomarker responses in fish are routinely used to assess exposure of anthropogenic chemicals in the aquatic environment. However, little is known about how cocktail effects affect these biomarker responses. For this reason, there is an obvious risk for misinterpretation of biomarker-data and this can have profound negative effects on stakeholder's decisions and actions, as well as on legislations and remediation-plans initiated in order to reduce exposure to certain chemicals. Besides, chemical safety-levels are traditionally based on experiences from lab-studies with single chemicals, which is unfortunate as a chemical can be more toxic when it is mixed with other chemicals, because of the cocktail effect. This review focuses on pharmacokinetic interactions between different classes of pollutants on detoxification mechanisms and how that affects two commonly used biomarkers in the aquatic environment: (1) induction of cytochrome P450 1A (CYP1A) that is mediated via activation of the arylhydrocarbon receptor (AhR), used to assess exposure to aromatic hydrocarbons; (2) induction of vitellogenin (VTG) that is mediated via activation of the estrogen receptor (ER), used to assess exposure to estrogenic chemicals. These responses can be either directly or indirectly affected by the presence of other classes of pollutants as a result of cocktail effects. For example, chemicals that inhibit the function of key metabolic enzymes and transporter pumps that are involved in elimination of AhR- and ER agonists, can result in bioaccumulation of aromatic hydrocarbons and estrogenic chemicals resulting in increased biomarker responses. This cocktail effect can lead to overestimation of the actual exposure pressure. On the contrary, induction of expression of key metabolic enzymes and transporter activities can result in increased elimination of AhR- and ER agonists that can lead to possible underestimation of the exposure. Another type of cocktail effect is inhibiting receptor cross-talk that may cause decreased biomarker responses that can also lead to underestimation of the actual exposure. To address the possible involvement of pharmacokinetic interactions including receptor cross-talks, we need to combine analyses on receptor signaling with studies on function of key biotransformation enzymes such as major catabolic CYP enzymes (e.g. CYP1-4) as well as efflux pumps (e.g. ATP-binding cassette transporter proteins). Besides, studies of inhibition of these enzymes and pumps activities pose a great potential to be used as future biomarkers as they are more clearly liked to adverse outcomes, compared to for example induction of CYP1A and VTG expression.

The effect of circulating estradiol concentrations on gonadotropin secretion in young and old castrated male-to-female transsexuals

CONTEXT

In aging men, circulating testosterone (T) declines which is associated with an increase in the levels of luteinizing hormone (LH) and follicle stimulating hormone (FSH) , albeit insufficient to maintain T at its original level. It has been speculated that a higher sensitivity of the hypothalamus and/or pituitary for the feedback effect of circulating sex hormones in older men is responsible.

OBJECTIVE

To compare the effect of experimentally varied plasma levels of estradiol on the LH and FSH secretion in young and old castrated male-to-female transsexuals, in almost absence of T. DESIGN, SUBJECTS, AND INTERVENTIONS: In 10 healthy, young (mean age 37.6 ± 6.2 years) and 11 healthy, old (mean age 68.1 ± 7.0) male-to-female transsexuals after gonadectomy plasma estradiol levels were experimentally varied with estradiol patches (the first week 100 μg/day patches, the second week 50 μg/day, the third week 25 μg/day and the fourth week no patch was applied) and plasma levels of LH and FSH were monitored after every week.

RESULTS

Mean plasma bioavailable estradiol (E2) levels in the two groups ranged between 13.6 and 104 pmol/l. LH and FSH were inversely related to peripheral estradiol levels, were lower in the old group at all time points reaching statistical significance in the last week of the study when no patch was applied and estradiol levels were extremely low.

CONCLUSIONS

The results of this study do not support the hypothesis of an age related increasing sensitivity of the hypothalamo-pituitary compartment for the negative feedback of E2, but suggest a deficient feed-forward drive in older male-to-female transsexuals.

Effect of ticagrelor on the pharmacokinetics of ethinyl oestradiol and levonorgestrel in healthy volunteers

BACKGROUND

Cytochrome P450 3 A is involved in ticagrelor and ethinyl oestradiol/levonorgestrel metabolism; so a potential drug-drug interaction may occur.

OBJECTIVES

To assess: ticagrelor effects on ethinyl oestradiol/levonorgestrel pharmacokinetics, endogenous sex hormone levels; ethinyl oestradiol/levonorgestrel effects on ticagrelor pharmacokinetics; tolerability of ticagrelor + ethinyl oestradiol/levonorgestrel.

METHODS

This trial was a randomized, double-blind, two-way crossover, single-center study. Twenty-two healthy female volunteers (on stable ethinyl oestradiol/levonorgestrel) received 90 mg ticagrelor or placebo twice daily with ethinyl oestradiol/levonorgestrel (0.03 mg/0.15 mg; Nordette) on cycle days 1-21. Volunteers crossed over treatment on day 1/cycle 2. Pharmacokinetic parameters were evaluated on cycle day 21, and endogenous hormones assayed on cycle days 1, 7, 14 and 21.

CLINICAL TRIAL REGISTRATION NUMBER

NCT006895906.

RESULTS

Ethinyl oestradiol absorption was rapid (median t(max) approximately 1 hour), and was not affected by ticagrelor. Ticagrelor co-administration (90% confidence interval [CI]) increased AUC(0-τ), C(min), and C(max) of ethinyl oestradiol by 20% (1.03-1.40), 20% (0.96-1.50) and 31% (1.18-1.44), respectively. Ticagrelor had no effect on levonorgestrel pharmacokinetic parameters versus placebo (90% CI: AUC(0-τ) 0.97-1.10; C(min) 0.94-1.10; C(max) 1.02-1.16). Steady-state ticagrelor, and AR-C124910XX (major and equally pharmacologically active metabolite), AUC(0-τ), C(max), and t(max) were comparable with published findings. Pre-dose ticagrelor and AR-C124910XX plasma concentrations were higher on cycle day 21 versus days 7 and 14. Endogenous sex hormone plasma levels were unaffected by ticagrelor. Co-administration of ticagrelor with ethinyl oestradiol/levonorgestrel was well tolerated. Study limitations included: no ticagrelor-only arm; only one type of oral contraceptive; short study duration; using oestradiol/levonorgestrel pharmacokinetic parameters as surrogate marker for contraceptive efficacy.

CONCLUSIONS

Ticagrelor co-administration with ethinyl oestradiol/levonorgestrel increased ethinyl oestradiol exposure by approximately 20%, with no effect on levonorgestrel pharmacokinetics. No clinically relevant effect on contraceptive efficacy is expected with ethinyl oestradiol/levonorgestrel and ticagrelor co-administration.

Soy extracts versus hormone therapy for reduction of menopausal hot flushes: indirect comparison

OBJECTIVE

The aim of this study was to make an indirect comparison of the results from meta-analyses that evaluated the severity of hot flushes in postmenopausal women exposed to hormone therapy (HT) or soy extracts.

METHODS

A systematic review and meta-analysis of HT and soy extracts related to the reduction of hot flushes in postmenopausal women versus the same control (placebo) were conducted. In addition, the combination of the overall results obtained from these two meta-analyses (indirect comparison) was adjusted to the common control (placebo).

RESULTS

The indirect standardized mean difference (SMD) obtained from the combination of both individual meta-analyses was calculated by using the following equation: SMD(indirect SOY vs HT) = SMD(soy) - SMD(HT), with a total indirect variance (var) equivalent to the following equation: var(total) = var(soy) + var(HT). These calculations yielded a point estimate of -0.84 (95% CI, -1.33 to -0.35) for the indirect SMD favorable to HT.

CONCLUSIONS

HT and soy interventions showed a significant difference in efficacy for the reduction of hot flushes in postmenopausal women when each treatment was compared with placebo. However, using indirect comparison, there is a statistically significant difference between HT and soy extracts in their effects on hot flushes.

Uptake and elimination, and effect of estrogen-like contaminants in estuarine copepods: an experimental study

BACKGROUND, AIM, AND SCOPE

In recent years, anthropogenic chemicals which can disrupt the hormonal systems of both humans and wildlife have been raised to a major cause of concern. The aim of the present work was to determine the bioconcentration factors of the two major alkylphenols (AP) of the Seine Estuary [4-nonylphenol (4 NP) and nonylphenol acetic acid (NP1EC)] and of the synthetic estrogen, estrogen ethinylestradiol (EE2), in Eurytemora affinis after exposure in a continuous flow-through system under environmental realistic conditions. Moreover, the elimination of these compounds in copepods from the Seine Estuary has been investigated by measuring concentrations after 1 week in clean water in comparison to background levels.

MATERIALS AND METHODS

In this study, the dominant copepod species of the Seine Estuary, E. affinis, was exposed at environmental relevant concentrations under laboratory-controlled conditions to selected waterborn contaminants, a mixture of 4 NP/NP1EC, and a synthetic EE2. The uptake and the elimination of these contaminants by E. affinis have been studied.

RESULTS

The results show that, at the end of the uptake period, both 4 NP and NP1EC, and also EE2 were accumulated in exposed copepods with respective concentration factors of 324, 3,020, and 5,383. A rapid elimination of these compounds was also observed in copepods placed in clean water since 54% of total NP1EC and 100% of EE2 amounts have been lost after 3 days. Pregnenolone was synthesized after exposure to EE2 and AP mixture.

DISCUSSION

These results demonstrate that E. affinis has the potency to accumulate but also to eliminate endocrine disrupters which suggests a non-negligible role of this copepod species in the biogeochemical cycles of these contaminants in estuarine ecosystems. Hence, these results also suggest that a transfer of 4 NP, NP1EC, and EE2 to copepod predators and subsequently that secondary poisoning of these organisms might be possible. Estrogen-like contaminants can induce pregnenolone synthesis and affect the reproduction of E. affinis.

CONCLUSIONS

These results suggest the important role of this copepod species in biogeochemical cycles of non-ionic surfactants as well as synthetic steroids in estuarine ecosystems.

RECOMMENDATIONS AND PERSPECTIVES

E. affinis could be a non-negligible route of exposure for juvenile fish and underline the potential for deleterious effects on copepod predators.

Contraceptive efficacy of oral and transdermal hormones when co-administered with protease inhibitors in HIV-1-infected women: pharmacokinetic results of ACTG trial A5188

BACKGROUND

Pharmacokinetic (PK) interactions between lopinavir/ritonavir (LPV/r) and transdermally delivered ethinyl estradiol (EE) and norelgestromin (NGMN) are unknown.

METHODS

Using a standard noncompartmental PK analysis, we compared EE area under the time-concentration curve (AUC) and NGMN AUC during transdermal contraceptive patch administration in HIV-1-infected women on stable LPV/r to a control group of women not on highly active antiretroviral therapy (HAART). In addition, EE AUC after a single dose of a combination oral contraceptive pill including EE and norethindrone was measured before patch placement and was compared with patch EE AUC in both groups. Contraceptive effects on LPV/r PKs were estimated by measuring LPV/r AUC at baseline and during week 3 of patch administration.

RESULTS

Eight women on LPV/r, and 24 women in the control group were enrolled. Patch EE median AUC0-168 h was 45% lower at 6010.36 pg·h·mL in those on LPV/r versus 10911.42 pg·h·mL in those on no HAART (P = 0.064). Pill EE median AUC0-48 hours was similarly 55% lower at 344.67 pg·h·mL in those on LPV/r versus 765.38 pg·h·mL in those on no HAART (P = 0.003). Patch NGMN AUC0-168 h however, was 138.39 ng·h·mL, 83% higher in the LPV/r group compared with the control AUC of 75.63 ng·h·mL (P = 0.036). After 3 weeks on the patch, LPV AUC0-8 h decreased by 19%, (P = 0.156).

CONCLUSIONS

Although PKs of contraceptive EE and NGMN are significantly altered with LPV/r, the contraceptive efficacy of the patch is likely to be maintained. Larger studies are indicated to fully assess contraceptive efficacy versus risks of the transdermal contraceptive patch when co-administered with protease inhibitors.

Pharmacokinetics of a modified-release estrogen tablet

OBJECTIVE

To determine steady-state plasma concentrations and the pharmacokinetic profile of the essential components of synthetic conjugated estrogens, B (SCE-B), particularly total estrone and delta8,9-dehydroestrone (DHE), after oral administration of a modified-released tablet.

STUDY DESIGN

A randomized, multiple-dose, pharmacokinetic study of 28 healthy, postmenopausal women randomly assigned to receive two SCE-B 0.3-mg tablets or one 1.25-mg tablet daily for 14 days. Blood samples were obtained before and after dosing at designated times. Total (conjugated and free) and unconjugated estrogens, namely estrone, equilin, and delta8,9-DHE, were determined, and pharmacokinetic analysis was performed.

RESULTS

Steady-state plasma levels of total estrone and total delta8,9-DHE measured on day 14 over a 24-hour period showed minor fluctuations and a similar time to maximum concentration (Tmax): mean Tmax of total estrone = 7.94 and 8.36 hours for 0.3-mg and 1.25-mg tablets, respectively; mean Tmax of total delta8,9-DHE = 7.08 and 8.36 hours for 0.3-mg and 1.25-mg tablets, respectively. Consistency in pharmacokinetic parameters was seen between the two doses of SCE-B.

CONCLUSION

SCE-B 0.3-mg and SCE-B 1.25-mg tablets achieved consistent pharmacokinetic parameters and steady-state levels when administered to healthy postmenopausal women. Achieving smooth, predictable levels of component estrogens may result in more consistent relief of menopausal symptoms.

Tissue distribution and elimination of estrogenic and anti-inflammatory catechol metabolites from sesaminol triglucoside in rats

Sesaminol triglucoside (STG) is the main sesame (Sesamum indicum L.) lignan. Like many other plant lignans, STG can be converted to the mammalian lignans by intestinal microbiota. The objectives of the present study were to investigate the distribution of STG metabolite in rats, and the effects of STG and its metabolite on in vitro inflammation and estrogenic activities. STG was metabolized via intestinal microflora to a biologically active catechol moiety which would then be absorbed into the body in rats. After oral administration of STG to Sprague-Dawley rats, the concentrations of major STG metabolites in rectum, cecum, colon, and small intestines are higher than those in liver, lung, kidney, and heart. Its concentration in brain is low but detectable. The present study demonstrates that STG may be metabolized to form the catechol metabolites first by intestinal microflora and then incorporated via intestine absorption into the cardiovascular system and transported to other tissues. Results showed that the catechol metabolites were found to be able to penetrate the tail end of intestines (large intestine) and go through urinary excretion. STG metabolites significantly reduced the production of IL-6 and TNF-alpha in RAW264.7 murine macrophages stimulated with lipopolysaccharide. The estrogenic activities of STG metabolites were also established by ligand-dependent transcriptional activation through estrogen receptors. This study clearly shows that STG has anti-inflammatory and estrogenic activities via metabolism of intestinal microflora.

Bioaccumulation of the synthetic hormone 17alpha-ethinylestradiol in the benthic invertebrates Chironomus tentans and Hyalella azteca

The present study investigated the bioaccumulation of the synthetic hormone 17alpha-ethinylestradiol (EE2) in the benthic invertebrates Chironomus tentans and Hyalella azteca, in water-only and spiked sediment assays. Water and sediment residue analysis was performed by LC/MS-MS, while biota extracts were analyzed using both LC/MS-MS and a recombinant yeast estrogen receptor assay. At the lowest exposure concentration, C. tentans accumulated less EE2 than H. azteca in the water-only assays (p=0.0004), but due to different slopes, this difference subsided with increasing concentrations; at the exposure concentration of 1mg/L, C. tentans had a greater body burden than H. azteca (p=0.02). In spiked sediments, C. tentans had the greatest EE2 accumulation (1.2+/-0.14 vs. 0.5+/-0.05 microg/gdw, n=4). Measurements in H. azteca indicated a negligible contribution from the sediments to the uptake of EE2 in this species. These differences were likely due to differences in the behavior and life history of the two species (epibenthic vs. endobenthic). Water-only bioaccumulation factors (BAFs) calculated at the lowest exposure concentration were significantly smaller in C. tentans than in H. azteca (31 vs. 142, respectively; p<0.0001). In contrast, the sediment bioaccumulation factor (BSAF) of C. tentans was larger than that of H. azteca (0.8 vs. 0.3; p<0.0001). Extracts of the exposed animals caused a response in a recombinant yeast estrogen receptor assay, thus confirming the estrogenic activity of the samples, presumably from EE2 and its estrogenic metabolites. The results of the present study suggest that consumption of invertebrate food items could provide an additional source of exposure to estrogenic substances in vertebrate predators.

Degradation rate constants of steroids in sewage treatment works and receiving water

Steroid estrogens are one of the most important groups of endocrine disrupting chemicals (EDCs) which can cause adverse effects on wildlife species and humans. Natural estrogens, including estrone (E1) and estradiol (E2), and synthetic estrogen 17alpha-ethinylestradiol (EE2) together contribute to most of the estrogenic activity in sewage effluents and receiving water. Degradation, particularly aerobic biodegradation was found to be the dominant removal mechanism in these environments. There are a number of factors such as temperature, pH, SRT, HRT and biomass concentration that can affect the rate of biodegradation. This paper reports the results of investigations in to the relationship between the equivalent biomass concentration and degradation rate constants for compounds E1, E2 and EE2 in various environments. It was found that a higher biomass concentration leads to higher rate constants, and relatively good linear correlations (R2 =0.73, 0.79 and 0.73) between the logarithm of the rate constants and the corresponding logarithm equivalent biomass concentration (EBC) values were obtained.

Comparativein vitrometabolism of the suspected pro-oestrogenic compound, methoxychlor in precision-cut liver slices from male and female rats

The in vitro metabolism of [14C]methoxychlor (MXC), a suspected pro-oestrogenic compound, by male and female Fischer rats (F344) was compared in precision-cut liver slices. The results demonstrated time-dependent metabolism of MXC with integrated phase I and II reactions, and the sex differences were detected in the metabolic profiles. In liver slices from male rats, MXC was metabolized to bis-demethylated MXC (bis-OH-MXC) by sequential O-demethylation followed by subsequent O-glucuronidation. The doubly conjugated metabolite, bis-OH-MXC 4-O-sulphate 4'-O-glucuronide was additionally produced. In the case of the female rat, the glucuronides of both mono- and bis-OH-MXC were formed as the main metabolites, and the mono-OH-MXC glucuronide appeared to be specific to the female rat. The ratios of bis-/mono-demethylated metabolite, which include the amounts of corresponding conjugates, were approximately 95/5 for the male rats and 40/60 for the female. These results imply that demethylation to the intermediate metabolite, (S)-mono-OH-MXC, is a key step for the sex-dependent metabolism of MXC in the rats. The phase I metabolites produced were extensively conjugated with D-glucuronic acid in both male and female rats.

Sex hormone concentrations and gonad histology in brown trout (Salmo trutta) exposed to 17beta-estradiol and bisphenol A

The impact of 17beta-estradiol (E2) and bisphenol A (BPA) on steroid hormone levels and gonad development in brown trout (Salmo trutta) was determined. Exposure took place from 0 to 63 days post-fertilisation (dpf) and gonad development was followed till 400 dpf. The onset of xenoestrogen metabolism was examined by measurements of whole body concentrations of bisphenol A (BPA) and its conjugation product bisphenol A glucuronic acid (BPAGA). Exposure to 500 ng E2/l led to an increase in E2 levels in the embryos and fry while 10 ng E2/l did not. Metabolic conversion of BPA to BPAGA began during the first weeks of embryonic development. Few consistent effects were found on the sex differentiation of the brown trout. Only one intersex fish (4.5%) was found among male fish at 400 dpf exposed to 500 ng E2/l. Females with male germ cells among the normally developing oocytes were observed in all groups (in up to 50% of the female fish, independently of exposure regime). The fact that exposure to 500 ng E2/l only caused subtle effects in a small number of individuals indicates that exposure during early life stages results in little to no induction of endocrine disruption in brown trout.

Effects of an oral contraceptive containing 30 mcg ethinyl estradiol and 2 mg dienogest on thyroid hormones and androgen parameters: conventional vs. extended-cycle use

BACKGROUND

This study was conducted to investigate the effects of an oral contraceptive containing 30 mcg ethinyl estradiol and 2 mg dienogest on thyroid hormones and androgen parameters.

STUDY DESIGN

Thyroid and androgen parameters were measured in 59 women treated with a monophasic combined oral contraceptive containing 30 mcg ethinyl estradiol and 2 mg dienogest (EE/DNG) either conventionally (13 cycles with 21 days of treatment+7 days without hormones) or according to an extended-cycle regimen (four extended cycles with 84 days of continuous administration of EE/DNG, followed by a hormone-free interval of 7 days). Blood samples were taken on Days 21-26 of the preceding control cycle and on Days 19-21 of the 3rd and 13th conventional cycle, or on Days 82-84 of the first and fourth extended cycle.

RESULTS

At both time points, the serum concentrations of thyroxine-binding globulin were elevated by about 65% in both treatment regimens. Likewise, both groups showed an increase in total triiodothyronine (T3) and total thyroxine (T4) by 30-40%, and no change in free T4. Until the 12th month of conventional treatment, the level of free T3 remained unchanged but decreased slightly during the extended-cycle regimen. In both groups there was a rise of sex hormone-binding globulin by 210-230% after 3 months and by 220-250% after 12 months. The levels of total testosterone were reduced by about 40% and those of free testosterone by 55-65% after 3 and 12 months.

CONCLUSION

The results suggest that, during conventional and extended-cycle treatment with EE/DNG, a steady state in the effects on thyroid hormones and androgen parameters was reached within 3 months and that the changes in the various hormonal parameters did not substantially differ between conventional and extended-cycle regimen.

Steady-state pharmacokinetics of conjugated equine estrogens in healthy, postmenopausal women

OBJECTIVE

To determine the steady-state exposure of conjugated and unconjugated estrogen components following oral administration of conjugated equine estrogens (2 0.625-mg tablets).

STUDY DESIGN

A prospective, open-label, single-treatment study conducted at 1 clinical site with 12 healthy, postmenopausal women. Each subject received 7 daily doses of 2 conjugated equine estrogen (0.625-mg) tablets, and blood samples were taken on the last day of dosing for pharmacokinetic analysis of estrogen components.

RESULTS

The major estrogen components after estrogen dosing (as determined by steady-state plasma concentration-time curves) were estrone (100 ng x h/mL), equilin (43.1 ng x h/mL) and delta8,9-dehydroestrone (13.6 ng x h/mL). Several 17beta-reduced forms of estrogen also had consistent plasma concentrations during a steady-state dosing interval. Mean t(max) values ranged from 6.2 to 9.0 hours after dosing, and the 24-hour profiles of the various plasma estrogen concentrations at steady state showed limited fluctuations.

CONCLUSION

Oral dosing of conjugated equine estrogen at steady state resulted in consistent concentrations of estrogen components during a dosing interval.

Drospirenone/ethinylestradiol 3mg/20microg (24/4 day regimen): a review of its use in contraception, premenstrual dysphoric disorder and moderate acne vulgaris

Drospirenone 3mg with ethinylestradiol 20microg (Yaz) is a low-dose combined oral contraceptive (COC) administered in a regimen of 24 days of active tablets followed by a short hormone-free interval (4 days; 24/4 regimen). Drospirenone, unlike other synthetic progestogens used in COCs, is a 17alpha-spirolactone derivative and a 17alpha-spironolactone analogue with antimineralocorticoid and antiandrogenic properties. Drospirenone/ethinylestradiol 3mg/20microg (24/4) is approved in the US for the prevention of pregnancy in women, for the treatment of the symptoms of premenstrual dysphoric disorder (PMDD) and for the treatment of moderate acne vulgaris in women who wish to use an oral contraceptive for contraception.Drospirenone/ethinylestradiol 3mg/20microg (24/4) provided 99% contraceptive protection over 1 year of treatment in two large studies. The same treatment regimen over three treatment cycles also significantly improved the emotional and physical symptoms associated with PMDD, and improved moderate acne vulgaris over six treatment cycles in double-blind trials. It was generally well tolerated, with adverse events generally typical of those experienced with other COCs and which were most likely to occur in the first few cycles. Clinical trials indicate that drospirenone/ethinylestradiol 3mg/20microg (24/4) is a good long-term contraceptive option, and additionally offers relief of symptoms that characterise PMDD and has a favourable effect on moderate acne vulgaris.

Enantioselectivity in estrogenic potential and uptake of bifenthrin

Despite the fact that the biological processes of chiral compounds are enantioselective, the endocrine disruption activity and uptake of chiral contaminants with respect to enantioselectivity has so far received limited research. In this study, the estrogenic potential and uptake of the enantiomers of a newer pyrethroid insecticide, bifenthrin (BF), were investigated. Significant differences in estrogenic potential were observed between the two enantiomers in the in vitro human breast carcinoma MCF-7 cell proliferation assay (i.e., the E-SCREEN assay) and the in vivo aquatic vertebrate vitellogenin enzyme-linked immunosorbent assay (ELISA). In the E-SCREEN assay, the relative proliferative effect ratios of 1S-cis-BF and 1R-cis-BF were 74.2% and 20.9%, respectively, and the relative proliferative potency ratios were 10% and 1%, respectively. The cell proliferation induced by the two BF enantiomers may be through the classical estrogen response pathway via the estrogen receptor (ER), as the proliferation induced by the enantiomers could be completely blocked when combined with 10-6 mol/L of the ER antagonist ICI 182,780. Measurement of vitellogenin induction in Japanese medaka (Oryzias latipes) showed that, at an exposure level of 10 ng/mL, the response to 1S-cis-BF was about 123 times greater than thattothe Renantiomer. Significant selectivity also occurred in the uptake of BF enantiomers in the liver and other tissues of J. medaka. These results together suggest that assessment of the environmental safety of chiral insecticides should consider enantioselectivity in acute and chronic ecotoxicities such as endocrine disruption.

Profiles of environmental and endogenous estrogens in the zebra mussel Dreissena polymorpha

Contamination of freshwater environments by estrogenic compounds has led to concern over potential impacts on invertebrate species. The uptake of the environmental estrogen 17beta-estradiol (E2) by the freshwater bivalve Dreissena polymorpha and the nature of estrogenic substances in tissues of D. polymorpha mussels collected from four freshwater sites were investigated. Exposure of mussels to [(14)C]-E2 (7.5 ngl(-1), 13 days) revealed that the estrogen bioconcentrated 840+/-58 (males) and 580+/-77 (females) fold (mean+/-95% confidence limits) and was metabolised in tissues to a persistent lipophilic ester. Estrogenic activity, measured using a recombinant human estrogen receptor transcription screen (YES), was detected in tissue extracts of all mussels sampled from freshwater sites. At two reference sites the estrogenic activities of mussel tissues were <1ng E2 equivalents g(-1) wet weight tissue (ng EEQ g(-1) ww) which increased to 7.4-45.7ng EEQg(-1) ww for both free and esterified estrogens extracted from hydrolysed tissue extracts. In mussels collected from two contaminated river sites, estrogenic activity was 0.2-6.7ng EEQ g(-1) ww (free estrogens) and 25.6-316.2ng EEQ g(-1) ww for total estrogens. Fractionation of the tissue extracts revealed that E2 (as the ester) was the predominant estrogen detected in both sexes of D. polymorpha, however, the xenoestrogen nonylphenol (NP) was also detected in mussels sampled from contaminated rivers. The detection of endogenous esterified E2 and the potential for accumulation of exogenous E2 and NP in D. polymorpha tissues suggests that this bivalve could be susceptible to exposure to estrogenic contaminants in the aquatic environment.

Lack of effect of rifalazil on ethinyl estradiol pharmacokinetics in healthy postmenopausal women

Rifalazil, a second-generation rifamycin, is being evaluated for the treatment of sexually transmitted disease and gastrointestinal infections. We determined whether rifalazil influences CYP3A4 metabolism by studying the effect of a single oral, 25 mg dose of rifalazil administered to healthy postmenopausal women, on the steady-state pharmacokinetics (PK) of ethinyl estradiol (EE) during administration of Ortho-Novum 1/35 (EE/NET). Noncompartmental PK and sequential statistical analyses were performed to establish if and when subjects achieved steady-state EE plasma concentrations and to determine whether this steady state was altered by rifalazil administration. The geometric mean ratios for the difference between EE alone and following rifalazil for EE Cmax, AUC(0-24) and Cmin were 105.9, 104.4 and 105.0, respectively. The 90% confidence intervals for each ratio fell within 80 - 125% of the reference treatment indicating no significant difference in the PK of EE before or after rifalazil administration. The posterior probabilities for the true treatment differences of Cmax or AUC(0-24) being less than 20% were > 99.99% in both cases. Based on the results of this study, there is no CYP3A4-metabolic interaction between a single oral, 25 mg dose of rifalazil and EE for either induction or inhibition. Consequently, there is minimal threat of contraceptive failure when single doses of rifalazil are administered with EE/NET. A single dose of rifalazil 25 mg was well tolerated when administered concomitantly with a combination oral contraceptive (EE/NET) by healthy postmenopausal females.

Parabens inhibit human skin estrogen sulfotransferase activity: Possible link to paraben estrogenic effects

Parabens (p-hydroxybenzoate esters) are a group of widely used preservatives in topically applied cosmetic and pharmaceutical products. Parabens display weak associations with the estrogen receptors in vitro or in cell based models, but do exhibit estrogenic effects in animal models. It is our hypothesis that parabens exert their estrogenic effects, in part, by elevating levels of estrogens through inhibition of estrogen sulfotransferases (SULTs) in skin. We report here the results of a structure-activity-relationship of parabens as inhibitors of estrogen sulfation in human skin cytosolic fractions and normal human epidermal keratinocytes. Similar to reports of paraben estrogenicity and estrogen receptor affinity, the potency of SULT inhibition increased as the paraben ester chain length increased. Butylparaben was found to be the most potent of the parabens in skin cytosol, yielding an IC(50) value of 37+/-5 microM. Butylparaben blocked the skin cytosol sulfation of estradiol and estrone, but not the androgen dehydroepiandrosterone. The parabens were also tested as inhibitors of SULT activity in a cellular system, with normal human epidermal keratinocytes. The potency of butylparaben increased three-fold in these cells relative to the IC(50) value from skin cytosol. Overall, these results suggest chronic topical application of parabens may lead to prolonged estrogenic effects in skin as a result of inhibition of estrogen sulfotransferase activity. Accordingly, the skin anti-aging benefits of many topical cosmetics and pharmaceuticals could be derived, in part, from the estrogenicity of parabens.

Effects of 17beta-estradiol and 4-nonylphenol on osmoregulation and hepatic enzymes in gilthead sea bream (Sparus auratus)

Sexually immature Sparus auratus were injected intraperitoneally with coconut oil either alone (control) or containing 17beta-estradiol (E2, 10 microg/g body mass) or 4-nonyphenol (4-NP, 100 and 200 microg/g body mass) and sampled 10 days later. Gill and kidney Na(+),K(+)-ATPase activities, plasma levels of E2 and cortisol, plasma osmolites (osmolality, sodium and chloride) and metabolites (glucose, lactate, proteins and triglycerides) were examined. Livers were used for measuring hepatosomatic index (HSI) and determinations of the activities of antioxidant defences catalase (CAT) and total glutatione peroxidase (t-GPX), the CYP1A-dependent, 7-ethoxyresorufin O-deethylase (EROD) and glutathione S-transferase (GST). HSI and plasma levels of E2 were significantly increased in E2 -treated fish. E2 treatment enhanced plasma osmolality, glucose, triglycerides and proteins, but had no effect on plasma cortisol, and gill and kidney Na(+),K(+)-ATPase activities. Hepatic activities of EROD, GST and CAT were significantly decreased after E2 administration, whereas t-GPX remained unaffected. Treatment with 200 microg/g 4-NP caused a slight increase in plasma E2 relative to the control group. Plasma glucose and protein levels were not affected by 4-NP, while triglycerides were increased. Fish treated with the higher dose of 4-NP displayed a clear reduction in kidney Na(+),K(+)-ATPase activity, together with increases in plasma osmolality, relative to the control group. High 4-NP also caused a significant decrease in EROD and an increase in GST activity. Our results confirm the regulation of the natural estrogen E2 and the weak xenoestrogen 4-NP on osmoregulation and biotransformation enzymes in a partially similar manner. The actions of xenoestrogens on critical physiological processes may have an ecological significance as it can reduce adaptability and capacity to metabolise xenobiotics under stressful conditions.

Identification of the steroid fatty acid ester conjugates formed in vivo in Mytilus edulis as a result of exposure to estrogens

Vertebrate-type sex steroids have been detected in a number of mollusk species and may play a role in the reproductive physiology of the animal. Mollusks are also exposed to exogenous estrogenic steroids that are present in sewage effluents, and these may add to the estrogenic burden of exposed animals. We investigated the uptake of estrogens in the blue mussel, Mytlius edulis and report for the first time the identity of estrogen fatty acid ester metabolites formed in vivo in an invertebrate. We exposed mussels to waterborne radiolabeled [(14)C]-17beta-estradiol (E2) or estrone (E1) and determined the nature of their metabolites using radio-HPLC and mass spectrometry (MS). After 13 days of exposure to 10ng/L E2, concentrations of radiolabeled residues were 2428-fold higher in M. edulis soft tissues compared with the ambient water concentration of E2. All the E2 residues in the mussel were present as a lipophilic ester which, in depuration studies, had a half-life of 8.3 days. Exposure of mussels to [(14)C]-E1 (70ng/L) resulted in formation of a similar lipophilic metabolite that after hydrolysis released [(14)C]-E2. Tandem MSMS analyses of the purified steroid ester fraction isolated from mussels exposed to either E2 or E1 revealed that they had the same composition and comprised C16:0, C16:1 and C16:2 esters of E2. This work reveals that in vivo E1 is rapidly metabolized to E2 in mussels prior to conjugation to C16 fatty acid esters, proving that C17-ketoreductase and C16 fatty acid acyl-CoA:E2 acyltransferase are important enzymes for the metabolism of estrogens in M. edulis.

Fate, transport, and biodegradation of natural estrogens in the environment and engineered systems

Natural steroidal estrogen hormones, e.g., estrone (E1), 17beta-estradiol (E2), estriol (E3), and 17alpha-estradiol (17alpha), are released by humans and livestock in the environment and are the most potent endocrine disrupters even at nanogram per liter levels. Published studies broadly conclude that conventional wastewater treatment is efficient in the removal of 17beta-estradiol (85-99%), but estrone removal is relatively poor (25-80%). The removal occurs mainly through sorption by sludge and subsequent biodegradation. The long solids retention time in wastewater treatment systems enhances estrogen removal due to longer exposure and the presence of a diverse microbial community, particularly nitrifiers. In spite of the treatment, the effluent from conventional biological wastewater treatment systems still contains estrogenic compounds at a level that may cause disruption of endocrine systems in some species. Advanced wastewater treatment systems such as membrane processes remove the estrogen compounds mainly through physical straining of particle-bound estrogens. Another major source, which accounts for 90% of the estrogen load, is animal manure from concentrated animal-feeding operations (CAFOs). Manure is not required to be treated in the United States as long as it is not discharged directly into water bodies. Thus, there is an urgent need to study the fate of animal-borne estrogens from these facilities into the environment. A number of studies have reported the feminization of male aquatic species in water bodies receiving the effluents from wastewater treatment plants (WWTPs) or surface runoff from fields amended with livestock manure and municipal biosolids. Estrogenicity monitoring studies have been conducted in more than 30 countries, and abundant research articles are now available in refereed journals. This review paper focuses on estrogen contributions by wastewater and livestock manure, their removal rate and mechanisms in an engineered system, and their transport and ultimate fate in an engineered system and the environment. The review aims to advance our understanding of fate, transport, and biodegradation of estrogen compounds and outlines some directions for future research.

Increases in serum estrogen levels during major illness are caused by increased peripheral aromatization

Although serum testosterone levels decrease acutely in critically ill patients, estrogen levels rise. We hypothesized that increased rates of aromatization of androgens to estrogens underlie the increase in serum estrogen levels. Eleven men and three women (age 42-69 yr) were prospectively studied before and again after elective coronary artery bypass graft surgery (CABG). Each patient received priming doses of [(14)C]androgen and [(3)H]estrogen that were immediately followed by peripheral infusions for 210 min. Eight men and three women received androstenedione (A(4))/estrone (E(1)) and three men received testosterone (T)/estradiol (E(2)). Adipose tissue biopsies were obtained in another six men before and after CABG to evaluate levels of P450 aromatase mRNA. Serum T levels decreased postoperatively in all 17 men (P < 0.001), whereas E(1) levels rose (P = 0.004), with a trend toward a rise in E(2) (P = 0.23). Peripheral aromatization rates of androgens to estrogens rose markedly in all 14 patients (P < 0.0001). Estrogen clearance rates rose (P < 0.002). Mean serum A(4) levels increased slightly postoperatively (P = 0.04), although no increase in A(4) production rates (PRs) was observed. T PRs decreased in two of three men, whereas clearance rates increased in all three. Adipose tissue P450 aromatase mRNA content increased postoperatively (P < 0.001). We conclude that the primary cause of increased estrogen levels in acute illness is increased aromatase P450 gene expression, resulting in enhanced aromatization of androgens to estrogens, a previously undescribed endocrine response to acute illness. Both increased T clearance and decreased T production contribute to decreased serum T levels. Animal studies suggest that these opposing changes in circulating estrogen and androgen levels may be important to reduce morbidity and mortality in critical illness.

Maternal exposure to endocrine-active substances and breastfeeding

Women pass on low levels of hazardous environmental contaminants and naturally occurring substances during pregnancy and nursing. In addition to estrogenic activity, these substances exhibit antiestrogenic, antiandrogenic, and androgenic actions, and because they can affect thyroid metabolism, they are described as endocrine-active substances (EAS). Specific topics related to EAS metabolism by mothers, fetuses, and infants are discussed. There is strong evidence that the assumed risk of EAS in early human development is exacerbated by interrupting neonatal priming provided by breastfeeding. The benefits of breastfeeding are fundamental to attenuate possible EAS effects on infants due to long-term intrauterine exposure. Breastfeeding is a guarantor of health benefits, whereas its alternative (infant formula) is a predictor of some health limitations. Mothers concerned with exposure to environmental contaminants should be advised of the proven benefits of breastfeeding and the possible health limitations of formula feeding.

Oral single pulse exposure of flounder Platichthys flesus to 4-tert-octylphenol: Relations between tissue levels and estrogenic effects

The accumulation of 4-tert-octylphenol and the associated estrogenic effects were studied after a single pulse exposure to flounder Platichthys flesus. 4-tert-octylphenol was administered orally in a single dose of 50 mg kg(-1) and tissue (liver, muscle and testis) and plasma concentrations of 4-tert-octylphenol as well as plasma vitellogenin were measured 3, 6, 12, 18, 24, 48, 72, 144 and 216 h after administration of the dose. Concentrations of 4-tert-octylphenol in plasma and tissues were determined by Liquid Chromatography Mass Spectrometry (LC-MS). 4-tert-octylphenol was detectable in liver, testis, muscle and plasma 3h post administration and an accumulation was observed in liver, muscle and plasma up to 12 h and in testis 18 h post administration, respectively. The maximum concentrations of 4-tert-octylphenol in liver, muscle and testis were 67, 3.2 and 6.8 microg g(-1), respectively. An increase in plasma vitellogenin levels was seen 48 h post administration and the vitellogenin level continued to increase (from <100 ng ml(-1) to 1.4 mg ml(-1)) until the end of the experiment 9 days after the administration of 4-tert-octylphenol.

Comparison of uterine concentrations of ethinyl estradiol and etonogestrel after use of a contraceptive vaginal ring and an oral contraceptive

OBJECTIVE

To compare uterine tissue concentrations of ethinyl estradiol (EE) and etonogestrel (ENG) after one cycle of use of a contraceptive vaginal ring (NuvaRing; NV Organon, Oss, The Netherlands) or a combined oral contraceptive (COC).

DESIGN

Randomized, open-label, pharmacokinetic study.

SETTING

Obstetrics and gynecology unit.

PATIENT(S)

Eight premenopausal women about to undergo hysterectomy but otherwise healthy.

INTERVENTION(S)

One cycle (17-21 days) of NuvaRing or COC treatment that ended with surgical hysterectomy.

MAIN OUTCOME MEASURE(S)

Tissue concentrations of EE and ENG in uterine tissue samples taken from the upper myometrium and mid-myometrium, the cervical region, and the endometrium.

RESULT(S)

In both groups, concentrations of EE and ENG were similar in uterine tissue taken from the upper myometrium and mid-myometrium and the cervical region. However, compared with the COC group, concentrations of both hormones were markedly lower in tissue samples from the endometrium of women who had been treated with NuvaRing.

CONCLUSION(S)

Vaginal administration of hormones with NuvaRing did not produce elevated uterine concentrations of EE and ENG, compared with an oral contraceptive.

Characterization of environmental estrogens in river water using a three pronged approach: active and passive water sampling and the analysis of accumulated estrogens in the bile of caged fish

Estrogenicity of river water is highly variable and it is difficult to obtain an average measure of the estrogenicity. Consequently it is difficult to tie the estrogenic effects observed in fish to their level of exposure to estrogens. To get a better handle on average estrogenic exposure we tested a recently developed passive sampling system (polar organic chemical integrative sampler, POCIS). In addition, we investigated the bioaccumulation of estrogens in caged brown trout and measured plasma vitellogenin in males as a bioindicator of estrogenic effects. We developed a mini-caging method to suit the hydrological conditions in small rivers and to improve upon the often poor survival of salmonids in caging trials. POCISs were positioned upstream and downstream of 5 sewage treatment works' discharges and left on site for 3 weeks (as were the caged fish), during which period 3 water grab samples were taken at each site. Concentrations of estrogens were determined using a yeast-based reporter gene assay and chemical analysis. Results from grab sampling, passive sampling, and bioaccumulation were correlated; however, plasma vitellogenin concentrations were elevated at only 1 of 5 sites. POCISs provide an integrated and biologically meaningful measure of estrogenicity in thatthey accumulate estrogens in a pattern similar to that of brown trout. Mini-caging appears a significant methodological advance; no fish were lost, moreover, all fish survived in excellent health.

Interaction of St. John's Wort with oral contraceptives: effects on the pharmacokinetics of norethindrone and ethinyl estradiol, ovarian activity and breakthrough bleeding

OBJECTIVES

This study evaluated the effect of the herbal remedy St. John's Wort on oral contraceptive (OC) therapy with respect to the pharmacokinetics of norethindrone and ethinyl estradiol, ovarian activity and breakthrough bleeding.

METHODS

Sixteen healthy women were treated with a low-dose OC (Loestrin 1/20) and a placebo for two consecutive 28-day cycles in a single-blind sequential trial. Treatment with St John's Wort 300 mg three times daily was then added for two additional 28-day cycles. Outcomes compared between control and treatment cycles included the pharmacokinetics of norethindrone and ethinyl estradiol, daily bleeding diaries, follicle growth, changes in cervical mucus and progesterone levels drawn at 7- to 10-day intervals.

RESULTS

Treatment with St. John's Wort was associated with a significant 13-15% reduction in the dose exposure from the contraceptive. Breakthrough bleeding increased in the treatment cycles, as did evidence of follicle growth and probable ovulation.

CONCLUSION

St. John's Wort is associated with increased metabolism of norethindrone and ethinyl estradiol, breakthrough bleeding, follicle growth and ovulation. Women using OCs should be cautioned that St. John's Wort might interfere with contraceptive effectiveness.

Effects of endogenous estrogen on renal calcium and phosphate handling in elderly women

High postmenopausal endogenous estrogen concentrations are an important determinant of preservation of bone mass and reduced fracture in elderly women. Calcium supplementation can also reduce bone loss in these patients, suggesting an interaction between estrogen deficiency and calcium balance. Potential mechanisms of estrogen on calcium transport include direct effects on the bone, the kidney, and the bowel. Previous studies have demonstrated effects of estrogen on renal phosphate handling. We have used a cross-sectional, population-based analysis of biochemical data obtained from ambulant elderly women to determine the association of endogenous estradiol with urine calcium and phosphorus excretion. The subjects were 293 postmenopausal women >70 yr old. Factors associated with renal calcium and phosphate excretion were measured, including the filtered calcium and phosphate load, parathyroid hormone (PTH), estradiol, and sex hormone-binding globulin (SHBG). The free estradiol concentration (FE) was calculated from a previously described formula. A high plasma estradiol concentration (r(2) = 0.023, P = 0.01) and a high FE (r(2) = 0.045, P = 0.001) were associated with reduced renal calcium excretion. The estradiol and FE effect on renal calcium excretion remained significant after adjusting for calcium filtered at the glomerulus and serum PTH. A high FE was associated with a reduced renal phosphate threshold in univariate analysis (r(2) = 0.023, P = 0.010). The effect remained significant after adjustment for serum PTH. The size of the effect of the FE was of the same order of magnitude as the effect of PTH on reducing renal calcium excretion and increasing renal phosphate excretion. These data support in vitro and animal data demonstrating an effect of estradiol on renal calcium and phosphate handling and indicate that, in elderly postmenopausal women, the effect is of a similar magnitude to the well-recognized effects of PTH on these physiologically regulated parameters.