The nature and utility of the phytoestrogens: a review of the evidence

Compositional changes induced by UV-B radiation treatment of common bean and soybean seedlings monitored by capillary electrophoresis with diode array detection

In this work, a new CE method with diode array detection (DAD) was developed for the monitoring and quantitation of flavonoids in different beans treated and untreated with UV-B radiation. Flavonoid concentration was monitored in UV-B-treated and untreated sprouts of three common beans (Zolfino ecotype, cv. Verdone, cv. Lingua di Fuoco) and one soybean (cv. Pacific). After acid hydrolysis of extracts, the CE-DAD method provides reproducible quantitative determinations of daidzein, glycitein, genistein, and kaempferol at ppm level in these natural matrices within a relatively short time (less than 16 min). Total flavonoid content determined by CE-DAD was 159 +/- 8, 26 +/- 2, 13 +/- 1, and 1.3 +/- 0.3 microg/g fresh weight for untreated sprouts of Pacific soybean, Verdone bean, Zolfino bean, and Lingua di Fuoco bean, respectively. UV-B treatment caused no significant quantitative effect on Pacific soybean sprouts, whereas it enhanced the total isoflavone content by 1.5, 1.8, and 3.2-fold in Verdone, Zolfino, and Lingua di Fuoco beans, respectively. The proposed method shows (i) the potentialities of bean sprouts as a natural source of bioactive compounds (antioxidants); (ii) the technological role of UV-B treatment for sprout isoflavone enrichment; and (iii) the good capabilities of CE-DAD to monitor this process.

Efficacy on menopausal neurovegetative symptoms and some plasma lipids blood levels of an herbal product containing isoflavones and other plant extracts

OBJECTIVES

To assess the efficacy of a product containing isoflavones and other plant extracts (BIO) on whole menopausal symptomatology and plasma lipids profile.

METHODS

Multicentre, randomized, double blind, placebo controlled clinical investigation on 125 menopausal women randomly assigned to two groups treated for 6 months with placebo or one tablet daily of an herbal product containing 72 mg/dose of isoflavones of different plants origin and other plant extracts (BIO). Primary end-point: Kupperman Menopause Index (KI) variations; secondary end-point: activity on plasma lipids profile and clinical global impression (CGI) on efficacy and tolerability by investigators and patients. The usual parametric test (paired Student t test) was performed to evaluate the significance. In case of non-applicability of parametric tests, the non-parametric Mann-Whitney U test was used. The differences where considered significant at p<0.05 level.

RESULTS

At the end of treatment in both groups KI showed a significant decrease (p<0.001). However, in the BIO group the KI reduction was significantly higher (p=0.0265) than in the placebo group after 4 and 6 months of treatment. In the BIO treated patients the LDL cholesterol showed a borderline but not significant reduction compared to placebo (p=0.0608) and triglyceride (TG) a significant (p=0.0151) decrease compared to placebo. The investigator's and patient's CGI on BIO group where superior as compared to placebo. Clinical tolerability was good in booth groups.

CONCLUSION

On the basis of positive effects on KI and lipids profile as well as of good clinical tolerability, BIO can be considered one of the possible alternative therapy for conventional HRT.

Aqueous extract of Schizandra chinensis fruit causes endothelium-dependent and -independent relaxation of isolated rat thoracic aorta

An aqueous extract of Schizandra chinensis fruit (ScEx) has long been used to promote the vascular health of postmenopausal women in Korea. This study investigated the ability of ScEx to relax rat aorta constricted with norepinephrine (NE) and the mechanism(s) of such relaxation. ScEx induced partial, endothelium-dependent relaxation. In particular, the relaxation induced by lower concentrations of ScEx (0.1 and 0.3 mg/ml) was largely endothelium-dependent, and was essentially abolished by NG-nitro-L-arginine, methylene blue, 1H-[1,2,3] oxadiazole [4,4-a] quinoxalin-1-one, indomethacin, or ICI 182,780. The results indicate that the response to ScEx involves enhancement of the nitric oxide (NO)-cGMP system, and that it occurs via estrogen receptors. The magnitude of the inhibition with these treatments decreased with increasing ScEx concentration, however, indicating that other vasorelaxation mechanisms are involved, which depend on the ScEx concentration. Calcium concentration-dependent contraction curves in high potassium depolarization medium were shifted significantly to the right and downward after incubation with ScEx (0.3 and 1.0 mg/ml), implying that ScEx is also involved in inhibition of the extracellular calcium influx to vascular smooth muscle. These data demonstrate that ScEx caused both endothelium-dependent and -independent vasorelaxation, which may contribute to understanding the cardiovascular protective effect of ScEx.

Evaluation of ex vivo human skin permeation of genistein and daidzein

The percutaneous absorption of genistein (GEN) and daidzein (DAI), whose oestrogenic-like activity is well known, is scantily investigated. In this work the ability of GEN and DAI to reach therapeutic steady-state plasma concentrations following transdermal administration was studied. The skin permeation studies were conducted by using modified Franz diffusion cell and human epidermis as a membrane. PEG400 was the most effective vehicle for both molecules. On the basis of the ex vivo permeation results and estimating therapeutic plasma concentration, we assume that pure GEN can be efficaciously administered by the transdermal route.

Hot flash therapies in breast cancer survivors

More than 86% of those diagnosed with invasive breast cancer are expected to survive for >/= 5 years after their diagnosis. Approximately 75% of postmenopausal women who had breast cancer report experiencing hot flashes. More than 90% of young survivors also experience hot flashes, which can be more severe and long lasting, with iatrogenic ovarian ablation or antiestrogen therapy. There are numerous options for the treatment of hot flashes. Not one treatment fits all. Some treatments are generally more effective than others, and each has different side effects. This review is meant to provide the basic information needed to make a decision about the best treatment for a breast survivor experiencing hot flashes.

Cross-cultural comparison of women's midlife symptom-reporting: a China study

Drawing on ethnographic and survey research conducted by the author in a general population sample in mainland China, this article presents findings on Chinese women's midlife symptom reporting in comparison with pivotal studies conducted by Lock, Kaufert, and McKinlay in Japan, Canada, and the U.S. Analysis of the China survey data (N = 156 women, age 45-55) reveals for sixteen core symptoms a reporting frequency that is much lower than depicted in classic biomedical models of menopause. At the same time, however, the China data indicates problems with the popular extrapolation that midlife Asian women are virtually symptom-free compared to their North American peers. Finding the Chinese level of symptom-reporting low to moderate depending on the symptom, the article reveals important differences between Chinese and Japanese women in their level and pattern of symptom reporting, as well as substantial overlap with North American women in this regard. Referencing ethnographic materials on Chinese women and the cross-cultural literature on menopause, the article assesses potential explanations for the cross-cultural variation observed, including: local reproductive endocrinology, phytoestrogen consumption, aspects of East Asian culture, the nature of social change, the cultural acceptability of monitoring and voicing symptoms, and differences in dominant conceptions of midlife.

Stimulatory effect of genistein and apigenin on the growth of breast cancer cells correlates with their ability to activate ER alpha

Genistein and apigenin are phytoestrogens present in commercial preparations used for the treatment of postmenopausal symptoms. In this study, we assessed the influence of these compounds on mammary tumor growth. Both compounds stimulate the proliferation of MCF-7 and T47D cells [estrogen receptor alpha (ERalpha-positive)], but do not stimulate the proliferation of an ERalpha-negative cell line (MDA-MB-435 cells). Genistein appeared more efficient in this regard due to its higher binding affinity for ERalpha, a property explained by a structural analysis of the binding of these compounds to the ERalpha's ligand binding domain. As previously described for estradiol (E(2)), genistein and apigenin down regulated ERalpha and enhanced estrogen response element (ERE)-dependent gene expression. The additional finding that genistein antagonizes the anti-proliferative effect of hydroxytamoxifen suggests phytoestrogens may be detrimental in women with breast cancer who are being treated with tamoxifen. In addition, because of their ability to stimulate breast cell growth, the widespread use of phytoestrogens in postmenopausal women could be detrimental.

Acupuncture and self acupuncture for long-term treatment of vasomotor symptoms in cancer patients--audit and treatment algorithm

INTRODUCTION

Since hormone replacement therapy given for long periods is now recognised to produce serious side effects, patients with troublesome vasomotor symptoms are increasingly using non-hormonal treatment including acupuncture. Several randomised controlled trials have shown that acupuncture reduces menopausal symptoms in patients experiencing the normal climacteric. It may have this effect by raising serotonin levels which alter the temperature set point in the hypothalamus. Vasomotor symptoms can be extreme in breast cancer patients and patients with prostate cancer who are undergoing anticancer therapy. The safety of some herbal medicines and phytoestrogens has been questioned, as they could potentially interfere adversely with the bioavailability of tumouricidal drugs. A previous study reports short term benefit from acupuncture, and the aim of this report is to describe our approach to long term treatment.

ACUPUNCTURE APPROACH

After piloting several approaches, six weekly treatments were given initially at LI4, TE5, LR3 and SP6 and two upper sternal points, but avoiding any limb with existing lymphoedema or prone to developing it. If there were no contraindications, patients were given clear instructions on how to perform self acupuncture using either semi-permanent needles or conventional needling at SP6, weekly for up to six years, for long term maintenance.

AUDIT METHODS AND RESULTS

A retrospective audit of electronic records was carried out by a doctor not involved in treatment. A total of 194 patients were treated, predominantly with breast and prostate cancer. One hundred and eighty two patients were female. The number of pre-treatment hot flushes per day was estimated by the patient: in the 159 cases providing adequate records, the mean was 16 flushes per day. Following treatment, 114 (79%) gained a 50% or greater reduction in hot flushes and 30 (21%) a less than 50% reduction. Treatment was abandoned in those who responded poorly or not at all. The duration of treatment varied from one month to over six years with a mean duration of nine months. Seventeen patients (9%) experienced minor side effects over the six year period, mostly minor rashes; one patient described leg swelling but this was likely to be due to a concurrent fracture.

CONCLUSION

Acupuncture including self acupuncture is associated with long-term relief of vasomotor symptoms in cancer patients. Treatment is safe and costs appear to be low. An algorithm is presented to guide clinical use. We recommend the use of self acupuncture with needles at SP6 in preference to semi-permanent needles in the first instance, but poor responders use indwelling studs if they fail to respond adequately to self acupuncture with regular needles. Point location may be of less importance than the overall 'dose', and an appropriate minimum dose may be required to initiate the effect.

Effect of genistein on the expression of bone metabolism genes in ovariectomized mice using a cDNA microarray

Osteoporosis associated with estrogen deficiency is defined as an abnormal decrease in bone mass leading to an increased fracture risk. Genistein (GEN), as a phytoestrogen, is a type of soybean-derived isoflavone that possesses structural similarity to estrogen. In this study, we assessed the effect of GEN in ovariectomized (OVX) mice. To determine the effect of GEN on bone metabolism, we investigated gene expression profiles using a radioactive cDNA microarray. Eight-week-old female mice were either sham operated (SHAM) or OVX. From 1 week after the operation, OVX mice were injected daily with intraperitoneal GEN (0.1, 0.5, 1.5 and 3.0 mg/day) or 17beta-estradiol (E2, 0.03 microg/day) for 4 weeks. A cDNA microarray was used to evaluate changes in the expression of 1,152 genes. OVX mice showed bone mineral density (BMD) loss versus SHAM mice (5.8+/-0.4 vs. 6.9+/-0.6 mg/cm2). However, femur BMDs were completely restored by GEN and by E2 administration in OVX mice. Serum osteocalcin in OVX mice treated with 0.5 mg/day of GEN was 1.6-fold (44.30+/-5.73 ng/ml) higher than that in untreated mice. GEN treatment up-regulated 38 genes (e.g., mitogen-activated protein kinase 10) and down-regulated 18 (e.g., matrix metalloproteinase 13). Moreover, GEN was found to have a protective effect on bone loss caused by estrogen deficiency in OVX mice. The present study suggests that GEN modulates bone metabolism-related gene expression, including calciotropic receptor, cytokines, growth factors and bone matrix proteins.

Hormone therapies in women aged 40 and older: Prevalence and correlates of use

CONTEXT

The objective of this paper is to report the prevalence and correlates of both prescription and non-prescription hormone use.

DESIGN/SETTING/SAMPLE

Cross-sectional baseline study from a prospective cohort of 30,448 women receiving mammography in New Hampshire.

MAIN OUTCOME MEASURES

Odds of prescription hormone and non-prescription hormone use.

RESULTS

29,851 women were included; 62% reported some use of prescription hormone therapy, with current long-term prescription hormone therapy users representing the largest group (25%). Among ever-users, estrogen only was the most commonly used preparation (71% versus 30% for estrogen and progestin combined). Both single agent estrogen and estrogen and progestin combined regimens were taken primarily for treatment of menopausal symptoms or disease prevention. Correlates for prescription hormone use included a family history of breast cancer (associated with decreased use-OR 0.88; 95% CI: 0.84, 0.93), and family history of heart disease (associated with increased use-OR 1.11; 95% CI: 1.06, 1.17). Ten percent of women reported ever use of phytoestrogens (over-the-counter hormones). Family history of breast cancer was a correlate of over-the-counter hormone use (OR 1.10; 95% CI: 1.01, 1.19).

CONCLUSION

Management of menopausal symptoms and disease prevention were the main reasons for using prescription hormones, and health histories were important correlates of both prescription and over-the-counter hormone exposures. As evidence changes regarding risks and benefits of hormone exposure, primary care physicians should help women reassess their use of hormonal agents.

Estrogen-related mood disorders: reproductive life cycle factors

Women are at higher risk throughout their reproductive lives than are men for major depression. Numerous molecular and clinical studies have implicated estrogen in modulating brain function including that related to mood. In an attempt to present a conceptual model, the literature of the past 30 years on mood and well-being throughout reproductive life is reviewed as it relates to activity of endogenous, bio-identical, and synthetic estrogen in women. Results indicate that sudden estrogen withdrawal, fluctuating estrogen, and sustained estrogen deficit are correlated with significant mood disturbance. Clinical recovery from depression postpartum, perimenopause, and postmenopause through restoration of stable/optimal levels of estrogen has been noted.

Polyunsaturated fatty acids (PUFAs) might reduce hot flushes: an indication from two controlled trials on soy isoflavones alone and with a PUFA supplement

OBJECTIVES

To investigate the effect on hot flushes of a soy isoflavone extract alone (Study A) and with the addition of a supplement of polyunsaturated fatty acids, PUFAs (Study B).

METHODS

Subjects were postmenopausal women (29 in Study A, 28 in Study B) with more than five troublesome hot flushes per day. Both studies were double-blind randomized placebo-controlled trials with cross-over design, of 24-week duration. After a 2-week observation period, they were randomized to receive two capsules per day providing 60mg of isoflavones or placebo for 12 weeks; thereafter, women who had taken isoflavones were given placebo for a second 12-week period, and vice-versa. Women in the Study B were given also two capsules per day containing a PUFA supplement for the entire 24-week test period.

RESULTS

Both studies showed the isoflavone extract to have no greater efficacy on hot flushes than the placebo. During the 24 weeks of the Study B there was a progressive and highly significant reduction in the number of hot flushes, independent of whether the women had begun with isoflavones or with placebo.

CONCLUSION

In these two trials the isoflavone extract did not show greater efficacy on the hot flushes than the placebo. The reduction of hot flushes observed in the Study B might be due to the PUFA supplement. PUFAs, particularly Omega (Omega) 3-fatty acids, could reduce hot flushes through their influence on neuronal membranes and/or the modulation of the neurotransmitter function and the serotoninergic system. Studies specifically designed to document the action of PUFAs on hot flushes would be welcome.

Phytoestrogens as cardioprotective agents

Epidemiologic studies have shown that women with a higher dietary intake of phytoestrogens, plant-derived compounds with partial estrogen agonist properties, have a lower incidence of cardiovascular disease and breast and uterine cancer than women with a lower dietary intake of these substances. The most-studied category of phytoestrogens is the isoflavones found in soybeans, chick peas, and other legumes. Genistein and daidzein are the 2 major forms of isoflavones and have demonstrated lipid-lowering properties, especially in hypercholesterolemic subjects. The mechanism for the hypocholesterolemic effects is unclear, but may involve altered hepatic metabolism, antioxidant properties, tyrosine kinase inhibition, and improved vascular reactivity. Other phytoestrogens, including coumestans and lignans, have shown unfavorable results with regard to their role in the prevention of coronary artery disease. Food and food supplements containing phytoestrogens are often advocated as an alternative to hormone replacement therapy (HRT) in women with contraindications to the use of conventional estrogen replacement or those wanting a natural alternative. In light of the recent trial results with HRT (estrogen plus progesterone), it would be prudent not to recommend phytoestrogens as cardioprotective substances until adequate safety and efficacy studies are completed.

Phytoestrogens derived from red clover: an alternative to estrogen replacement therapy?

The benefits of plant extracts from soy and red clover as alternatives to conventional hormone replacement therapy (HRT) have been debated in the past. Here, an attempt has been made to summarize the biochemical and pharmacological data in the light of clinical aspects. Red clover and soy extracts contain isoflavones, which have a high affinity to estrogen receptor alpha (ERalpha), estrogen receptor beta (ERbeta), progesterone receptor (PR) and androgen receptor (AR). The higher affinity to ERbeta compared to ERalpha has been used as an explanation why red clover extracts function as food additives to treat menopausal disorders and may reduce risk of breast cancer. Biochemical analysis shows that these representatives of phytoestrogens have multiple actions beside selective estrogen receptor modulator (SERM)-activity. They act as selective estrogen enzyme modulators (SEEMs), have antioxidant activity and interact with transcription factors such as NF-kappaB. Furthermore, it is indicated that they have protective effects on osteoporosis and the cardiovascular system. Currently 40-50mg of isoflavones (biochanin A, daidzein, formononetin and genistein) are recommended as daily dose. This recommendation is based on the daily intake of phytoestrogens in a traditional Japanese diet.

Strategies for managing breast cancer risk after the menopause

Postmenopausal women in Western societies are conscious of breast cancer as a potential cause of death and ill health, which they wish to avoid with the advice of their doctors. Yet many factors that predispose women to the development of cancer will have been laid down before the menopause, in their genetic makeup or during their adolescent years. Even in middle age it is important to take account of the intrinsic level of risk, and to give women advice tailored to their own individual risk level. This results from their family history, previous diseases such as benign breast disease, and previous treatment for breast cancer or Hodgkin's disease. For those at the highest level of risk, strategies will include regular screening, prophylactic mastectomy, and the use of chemoprevention agents, such as tamoxifen. These women should avoid hormone replacement therapy (HRT) and control their menopausal symptoms and osteoporosis through the use of other agents now available - venlafaxine for menopausal symptoms and bisphosphonates for osteoporosis. Raloxifene is an agent under trial that may be valuable for breast cancer control as well as for osteoporosis. Women at standard population risk will require less robust preventive strategies, which will include screening and lifestyle modification. Their decisions regarding HRT should now be modified by recent evidence of associated risks. Recent studies show that tibolone causes less mammographic density and has a lower relative risk of breast cancer than combined estrogen/progestogen preparations. There is limited evidence that controlling obesity, participating in exercise and adopting a diet low in fats and high in fruit and vegetables will alter risk at this age. These precautions will, however, reduce the risk of other diseases common in this age group, such as hypertension, heart disease, stroke, and type 2 diabetes mellitus. Alcohol, even in small amounts, is a risk factor for breast cancer. Given the cardioprotective effect of moderate alcohol intake, advice on alcohol must reflect the individual relative risk of cardiovascular disease and breast cancer. Personal risk assessment is relevant for all women. Screening and a healthy lifestyle are worthwhile approaches for all, with the more aggressive approaches such as chemoprevention and prophylactic surgery reserved for those who have substantially elevated levels of risk. Once the menopause has passed, screening is probably the most effective evidence-based tool for breast cancer control by early diagnosis.

Lack of effect of isoflavonoids on the vagina and endometrium in postmenopausal women

OBJECTIVE

To determine the effects of soy-derived isoflavones on vaginal epithelium and the endometrium.

DESIGN

Double-blind, randomized, placebo-controlled crossover trial.

SETTING

Outpatient clinic of a university hospital.

PATIENT(S)

Sixty-four postmenopausal women with a history of breast cancer.

INTERVENTION(S)

The women took (in a randomized order) 114 mg of isolated isoflavonoids or placebo in tablets daily for 3 months; the treatment regimens were crossed over after a 2-month washout period. The subjects were studied before and on the last day of each treatment period.

MAIN OUTCOME MEASURE(S)

Vaginal dryness, maturation index (MI) of vaginal epithelium, endometrial thickness, histology, and expression of estrogen (E) and progesterone (P) receptors and the proliferation marker Ki-67 in the endometrium.

RESULT(S)

Isolated isoflavones did not relieve vaginal dryness. Maturation index values remained unchanged during the isoflavone regimen, but decreased during the placebo regimen. No changes were found in any of the variables measured in the endometrium.

CONCLUSION(S)

Daily administration of 114 mg of isolated isoflavones for 3 months had no effect on the subjective perception of vaginal dryness or on objective findings in the vagina or endometrium. This implies safety with regard to the endometrium.

Estrogenic activity of a polyphenolic extract of the leaves of Epimedium brevicornum

The estrogenic activity of a polyphenolic extract of the leaves of Epimedium brevicornum and five fractions obtained by solid-phase extraction were investigated using estrogen-responsive bioassays, a yeast cell assay and the Ishikawa Var-I assay. The extract was found to exhibit significant estrogenic activity in both assays. Furthermore, bioassay-guided fractionation led to localisation of the estrogenicity in the relatively non-polar fractions of the polyphenolic extract.

Soy isoflavone phyto-pharmaceuticals in interleukin-6 affections. Multi-purpose nutraceuticals at the crossroad of hormone replacement, anti-cancer and anti-inflammatory therapy

Interleukin-6 is a pleiotropic cytokine which plays a crucial role in immune physiology and is tightly controlled by hormonal feedback mechanisms. After menopause or andropause, loss of the normally inhibiting sex steroids (estrogen, testosterone) results in elevated IL6 levels that are further progressively increasing with age. Interestingly, excessive IL6 production promotes tumorigenesis (breast, prostate, lung, colon, ovarian), and accounts for several disease-associated pathologies and phenotypical changes of advanced age, such as osteoporosis, rheumatoid arthritis, multiple myeloma, neurodegenerative diseases and frailty. In this respect, pharmacological modulation of IL6 gene expression levels may have therapeutical benefit in preventing cancer progression, ageing discomforts and restoring immune homeostasis. Although "plant extracts" are used in folk medicine within living memory, it is only since the 20th century that numerous scientific investigations have been performed to discover potential health-protective food compounds or "nutraceuticals" which might prevent cancer and ageing diseases. About 2000 years ago, Hippocrates already highlighted "Let food be your medicine and medicine be your food". Various nutrients in the diet play a crucial role in maintaining an "optimal" immune response, such that deficient or excessive intakes can have negative consequences on the organism's immune status and susceptibility to a variety of pathologies. Over the last few decades, various immune-modulating nutrients have been identified, which interfere with IL6 gene expression. Currently, a broad range of phyto-pharmaceuticals with a claimed hormonal activity, called "phyto-estrogens", is recommended for prevention of various diseases related to a disturbed hormonal balance (i.e. menopausal ailments and/or prostate/breast cancer). In this respect, there is a renewed interest in soy isoflavones (genistein, daidzein, biochanin) as potential superior alternatives to the synthetic selective estrogen receptor modulators (SERMs), which are currently applied in hormone replacement therapy (HRT). As phyto-chemicals integrate hormonal ligand activities and interference with signaling cascades, therapeutic use may not be restricted to hormonal ailments only, but may have applications in cancer chemoprevention and/or NF-kappaB-related inflammatory disorders as well.

Nonpharmacological prevention of osteoporotic fractures

In postmenopausal women, the nonpharmacological prevention of osteoporotic fractures pursues the dual objective of minimizing bone loss and preventing falls. In women with a low fracture risk, optimizing the dietary intake of calcium is the main nutritional goal. Regular sustained physical activity should be encouraged. In older women, the high risk of proximal femoral fractures warrants a number of preventive measures, including calcium and vitamin D supplementation, correction of protein deficiency if needed, and minimization of the risk of falls. Hip protectors may be useful in institutionalized women at high risk for falls. These nonpharmacological measures should be part of a comprehensive customized management program used to complement standard pharmacological therapy.

Proteins of multiple classes may participate in nongenomic steroid actions

Responses to steroids initiated from non-nuclear receptors impinge on a wide variety of cellular responses and utilize nearly all known signal transduction webs. While the mechanisms by which steroid receptors localize in the membrane are still unclear, it is apparent that this alternative localization allows steroid receptors to participate in a wide range of complex functions influencing cell proliferation, death, and differentiation. The central debate still remains the identity of the protein class or classes that mediate membrane-initiated (nongenomic) responses. The data thus far have supported several possibilities, including: nuclear steroid receptor-like forms in non-nuclear locations; other known (nonsteroid) membrane receptors or channels with additional steroid-binding sites; enzymes; transporters; receptors for serum steroid-binding proteins; unique and previously undescribed proteins; or chimeras of typical steroid receptor domains with other unique or known protein domains. Categorizing membrane steroid receptor proteins based exclusively on the actions of antagonists and agonists, without considering cell context and protein partnering issues, may mislead us into predicting more receptor subtypes than really exist. However, the plethora of signaling and functional outcomes may indicate the participation of more than one kind of steroid-binding protein. Resolving such unanswered questions will require future investigative focus on this alternative arm of steroid action, which is likely to yield as many therapeutic opportunities as have nuclear steroid mechanisms.

[Phytotherapy in menopausal symptoms]

Neben der Hormontherapie werden Nahrungsergänzungsmittel und Phytotherapeutika zur Behandlung des klimakterischen Syndroms eingesetzt. Phytoestrogene (Soja, Rotklee) sind einer Placebobehandlung bei der Therapie klimakterischer Beschwerden kaum überlegen, erscheinen hingegen wirksam zur Osteoporosevorbeugung. Es mehren sich allerdings Zweifel an der Sicherheit der Isoflavonpräparate. Die Wirksamkeit der Traubensilberkerze ist durch kontrollierte klinische Studien belegt. Sie ist der HT ebenbürtig und zeichnet sich, bei einem langsameren Wirkungseintritt, gegenüber der HT durch eine bessere Verträglichkeit aus. Es existieren Hinweise auf einen osteoprotektiven Effekt, der in weiteren Langzeitstudien bestätigt werden muss. Cimicifuga‐Präparate können an estrogenresponsivem Gewebe, wie Brust und Uterus, als sicher angesehen werden. Patientinnen, die eine HT ablehnen oder nicht anwenden dürfen, steht mit den Cimicifuga‐Präparaten eine wirksame und gut verträgliche Alternative zur Verfügung.

Oestrogen receptor-beta and neurohypophysial hormones: functional interaction and neuroanatomical localisation

Oestrogens affect fluid balance, influencing both ingestive behaviour and renal excretion. The renal effects are partly due to altered release of vasopressin and oxytocin. This study was designed to explore the role of oestrogen receptor-beta (ERbeta) in neurohypophysial hormonal function. Following dietary administration, soya isoflavones reach the brain in sufficient concentration to activate ERbeta, but not oestrogen receptor-alpha (ERalpha). ERbeta function was therefore manipulated by feeding rat diets differing in soya isoflavone content. Fluid balance and neurohypophysial hormone release were measured in male rats maintained for 14 days on a soya isoflavone-free diet or one containing 150 microg/g genistein+daidzein. Food and water intake, body weight, urine flow, osmolality and sodium concentrations were determined daily. After 14 days, plasma and urine osmolality and sodium, vasopressin and oxytocin concentrations were determined. There was no significant difference in weight gain between the two groups or in their excretion of sodium and water or plasma sodium and plasma oxytocin. However, plasma vasopressin was significantly lower in the iso-free group. Double-label immunocytochemistry was used to assess colocalisation of ERbeta with the neurohypophysial hormones in male rats. Cell nuclei showing ERbeta immunoreactivity were abundant in the posterior magnocellular paraventricular nucleus (PVNpm) and in the supraoptic nucleus (SON). Vasopressin-immunoreactive neurones were similarly distributed, forming the core of the PVNpm and the ventral portion of the SON; majority were positive for ERbeta. Cells with oxytocin immunoreactivity were located mainly at the periphery of the PVNpm and in the dorsal SON; only approximately a quarter of these cells showed ERbeta immunoreactivity. Thus, the difference in the effects of the soya diet on vasopressin and oxytocin release may be related to the ERbeta-activating properties of this diet and to the preponderance of this receptor in vasopressin as opposed to oxytocin cells.

Soy isoflavones: hope or hype?

Approximately 50% of Americans use dietary supplements on a regular basis spending an estimated $20 billion on supplements in the year 2000. Soy contains genistein and daidzein, two phytoestrogens, which work through the estrogen receptor and cause alterations in serum lipids, bone metabolism, and possibly cognition. In this article, we review the issues regarding the interpretation with studies using soy-based isoflavones, discuss their mechanism of action, and review the literature on the effect of these bio-active compounds on lipid metabolism, osteoblasts and osteoclasts, bone markers, bone mineral density, and cognition.

Breast cancer and post-menopausal hormone therapy

From the introduction of post-menopausal hormone replacement therapy (HRT) there has been great concern that HRT could possibly increase the risk of breast cancer. Prolonged exposure to endogenous oestrogens undeniably increases the risk of breast cancer. Questions that are important and until now only partly answered, are the following. Are oestrogens tumour promoters, as they induce mitosis, lead to proliferation and, therefore, accelerated growth of clinically occult pre-existing tumours? In addition to this, are they genotoxic mutagenic carcinogens, or could they initiate tumours by way of accumulation of incessant DNA-replication damage mechanism? Opinions vary as to the effect of the addition of a progestogen. There is a multitude of different progestogens which could bind with differing affinity to progesterone receptor PR-A or PR-B, and which have different physiological functions via differential gene regulation. The action of a progestogen on the oestrogen-induced cellular mitotic activity could be synergistic or antagonistic (by different pathways: oestrogen receptor downregulation, activating of metabolic pathways within the breast or stimulation of apoptosis)? Over 60 observational studies and two randomized trials provide evidence that the small but significant increase in risk appears with long-term current post-menopausal hormone use. The addition of a progestogen does not decrease the risk as seen with oestrogens alone and might increase the risk further. It is not clear whether there is a difference in risk with sequentially combined versus continuously combined HRT. Many questions nevertheless still remain. Is the risk increase limited to lean women only? What about risk-modifying factors such as alcohol use and a positive family history for breast cancer? Are tumours detected under HRT less aggressive, is there a better prognosis and is the mortality not increased while morbidity is? And is HRT contraindicated for women with a positive family history for breast cancer or in those women who have been treated for breast cancer? And finally, are there alternative options for these women?