Effects of percutaneous estradiol and conjugated estrogens on the level of plasma proteins and triglycerides in postmenopausal women

Menopause and diabetes

In the last 20 years, the prevalence of type 2 diabetes mellitus (T2DM) has tripled in adults aged 20-79 years, affecting more than 25% of people over 50 years of age and especially women during menopause. After the menopause transition, women gain weight, increasing abdominal fat and decreasing lean body mass, with a significant reduction in energy expenditure. Increased insulin resistance and hyperinsulinism characterize this period, aggravated by an increase in plasma proinflammatory cytokines and free fatty acids, and a state of relative hyperandrogenism. Previous recommendations systematically excluded women with T2DM from menopause hormone therapy (MHT); new evidence confirms that MHT significantly reduces the diagnosis of new-onset T2DM and may be beneficial in terms of glycemic control when used for menopause symptom management in patients with pre-existing T2DM. A comprehensive and individualized approach is considered the first line of management for women during this period, especially in T2DM patients or in women at risk of developing the disease. The objectives of this presentation are to review the etiopathogenic factors involved in the increased incidence of new cases of T2DM during menopause, the impact of menopause on T2DM and the role of MHT.

Diabetes in Menopause: Risks and Management

The aim of this review is to present, critically appraise and qualitatively synthesize current evidence on the risk of type 2 diabetes mellitus (T2DM) development during menopause, the management of climacteric symptoms in women with T2DM and the management of T2DM in postmenopausal women. Menopause represents the end of reproductive life in women, as a result of ovarian aging. It is characterized by substantial decrease in the endogenous oestrogen concentrations and it is accompanied by alterations in body weight, adipose tissue distribution and energy expenditure, as well as insulin secretion, insulin sensitivity and activity that can predispose to the development of T2DM, independently of, and additively to, aging. Many women in midlife experience climacteric symptoms, including hot flushes and night sweats, resulting in an indication to receive Hormone Replacement Treatment (HRT). HRT has a favourable effect on glucose homeostasis both in women without and with T2DM. The latter was considered in the past as a cardiovascular disease (CVD) equivalent, which would suggest that women with the disease should not receive HRT. However, nowadays evidence exists to support an individualized approach of women based on their CVD risk, as some women with T2DM may be excellent candidates for HRT. Regarding T2DM management for women in menopause, lifestyle intervention, including diet and exercise, constitutes its cornerstone. However, most of these women will eventually require pharmacologic therapy. The most suitable agents should be selected according to their metabolic, cardiovascular and bone effects, taking into consideration the specific characteristics and comorbidities of each postmenopausal woman.

Type 2 Diabetes Mellitus and Menopausal Hormone Therapy: An Update

During menopausal transition, various phenotypical and metabolic changes occur, affecting body weight, adipose tissue distribution and energy expenditure as well as insulin secretion and sensitivity. Taken together, these can predispose women to the development of type 2 diabetes mellitus (T2DM). Many women in midlife experience climacteric symptoms, including hot flashes and night sweats. Menopausal hormone therapy (MHT) is then indicated. MHT has a favourable effect on glucose homeostasis in both women without and with T2DM. T2DM was considered in the past as a cardiovascular disease (CVD) equivalent, which would suggest that women with T2DM should not receive MHT. This notion may still deter many clinicians from prescribing MHT to these patients. However, nowadays there is strong evidence to support an individualised approach after careful evaluation of CVD risk. In older women with T2DM (> 60 years old or > 10 years in menopause), MHT should not be initiated, because it may destabilise mature atherosclerotic plaques, resulting in thrombotic episodes. In obese women with T2DM or in women with moderate CVD risk, transdermal 17β-oestradiol could be used. This route of delivery presents beneficial effects regarding triglyceride concentrations and coagulation factors. In peri- or recently post-menopausal diabetic women with low risk for CVD, oral oestrogens can be used, since they exhibit stronger beneficial effects on glucose and lipid profiles. In any case, a progestogen with neutral effects on glucose metabolism should be used, such as natural progesterone, dydrogesterone or transdermal norethisterone. The goal is to maximise benefits and minimise adverse effects.

Impact of 17β-estradiol on complex I kinetics and H2O2 production in liver and skeletal muscle mitochondria

Naturally or surgically induced postmenopausal women are widely prescribed estrogen therapies to alleviate symptoms associated with estrogen loss and to lower the subsequent risk of developing metabolic diseases, including diabetes and nonalcoholic fatty liver disease. However, the molecular mechanisms by which estrogens modulate metabolism across tissues remain ill-defined. We have previously reported that 17β-estradiol (E2) exerts antidiabetogenic effects in ovariectomized (OVX) mice by protecting mitochondrial and cellular redox function in skeletal muscle. The liver is another key tissue for glucose homeostasis and a target of E2 therapy. Thus, in the present study we determined the effects of acute loss of ovarian E2 and E2 administration on liver mitochondria. In contrast to skeletal muscle mitochondria, E2 depletion via OVX did not alter liver mitochondrial respiratory function or complex I (CI) specific activities (NADH oxidation, quinone reduction, and H2O2 production). Surprisingly, in vivo E2 replacement therapy and in vitro E2 exposure induced tissue-specific effects on both CI activity and on the rate and topology of CI H2O2 production. Overall, E2 therapy protected and restored the OVX-induced reduction in CI activity in skeletal muscle, whereas in liver mitochondria E2 increased CI H2O2 production and decreased ADP-stimulated respiratory capacity. These results offer novel insights into the tissue-specific effects of E2 on mitochondrial function.

A prodrug design for improved oral absorption and reduced hepatic interaction

A series of estradiol-17-β esters of N-(p-sulfomylbenzamide)-amino acids were prepared and evaluated for systemic and hepatic estrogenic activity after oral administration in ovariectomized rats. The alkyl substitution at nitrogen of amino acids such as proline or N-methyl-alanine produced compounds that exhibit potent oral activity. The proline analog (EC508) was further evaluated along with 17β-estradiol (E2) and ethinyl-estradiol (EE) and compared their effects on the uterus, angiotensin and HDL-cholesterol after oral administration to ovariectomized female rats. Orally administered EC508 produced systemic estrogenic activity 10 times greater than EE and a 100 times higher activity than E2 with no influence on levels of angiotensin and HDL-cholesterol, whereas EE and E2 reduced the HDL-cholesterol and increased the angiotensine plasma levels. EC508 might offer significant advantages in indications like fertility control and HRT based on its high oral bioavailability and lack of hepatic estrogenicity.

Menopausal Hormone Therapy and Type 2 Diabetes Prevention: Evidence, Mechanisms, and Clinical Implications

Type 2 diabetes has reached epidemic proportions in the United States. Large, randomized controlled trials suggest that menopausal hormone therapy (MHT) delays the onset of type 2 diabetes in women. However, the mechanisms and clinical implications of this association are still a matter of controversy. This review provides an up-to-date analysis and integration of epidemiological, clinical, and basic studies, and proposes a mechanistic explanation for the effect of menopause and MHT on type 2 diabetes development and prevention. We discuss the beneficial effects of endogenous estradiol with respect to insulin secretion, insulin sensitivity, and glucose effectiveness; we also discuss energy expenditure and adipose distribution, both of which are affected by menopause and improved by MHT, which thereby decreases the incidence of type 2 diabetes. We reconcile differences among studies that investigated the effect of menopause and MHT formulations on type 2 diabetes. We argue that discrepancies arise from physiological differences in methods used to assess glucose homeostasis, ranging from clinical indices of insulin sensitivity to steady-state methods to assess insulin action. We also discuss the influence of the route of estrogen administration and the addition of progestogens. We conclude that, although MHT is neither approved nor appropriate for the prevention of type 2 diabetes due to its complex balance of risks and benefits, it should not be withheld from women with increased risk of type 2 diabetes who seek treatment for menopausal symptoms.

The role of estrogens in control of energy balance and glucose homeostasis

Estrogens play a fundamental role in the physiology of the reproductive, cardiovascular, skeletal, and central nervous systems. In this report, we review the literature in both rodents and humans on the role of estrogens and their receptors in the control of energy homeostasis and glucose metabolism in health and metabolic diseases. Estrogen actions in hypothalamic nuclei differentially control food intake, energy expenditure, and white adipose tissue distribution. Estrogen actions in skeletal muscle, liver, adipose tissue, and immune cells are involved in insulin sensitivity as well as prevention of lipid accumulation and inflammation. Estrogen actions in pancreatic islet β-cells also regulate insulin secretion, nutrient homeostasis, and survival. Estrogen deficiency promotes metabolic dysfunction predisposing to obesity, the metabolic syndrome, and type 2 diabetes. We also discuss the effect of selective estrogen receptor modulators on metabolic disorders.

[Rationalizing progestin-only contraception (except IUS with levonorgestrel)]

Using pure progestin contraception has four main objectives; all pure progestins on the market do not satisfy these four main objectives: (i) not to give artificial estrogens like ethinyl estradiol or any kind of estrogens at high doses. This is necessary when there is an estrogeno-dependent pathology; (ii) to diminish endogen estrogen circulating levels by using anti-gonadotrope progestins; (iii) not to induce dangerous proteins synthesis by a too important estrogenic hepatic impact due to an effect, known as hepatic passage. This is required in case of metabolic pathologies or more largely, in case of important vascular risk factors or also in case of an estrogen-dependent hepatopathy; to diminish hormonal fluctuations for women who have problems due to varying endogen hormones. Knowing each product's pharmacology enables to choose the product best adapted to each clinical situation. When choosing, one has to take into account the contraceptive efficiency, as well as the fact that those products are often given over long periods of time to women with particular pathologies.

Effects of non-oral postmenopausal hormone therapy on markers of cardiovascular risk: a systematic review

OBJECTIVE

To review the effects of non-oral administration of postmenopausal hormone therapy (HT) on risk markers for atherosclerotic and venous thromboembolic disease.Non-oral postmenopausal HT appears not to increase venous thromboembolic risk, whereas the effect on coronary heart disease risk is less clear.

DESIGN

Systematic review of literature obtained from MEDLINE, EMBASE, and CENTRAL databases from 1980 until and including April 2006. Terms for "postmenopausal hormone therapy" and for "non-oral administration" were combined in the search.

SETTING

Randomized clinical trials.

PATIENT(S)

Postmenopausal women, both healthy and with established cardiovascular disease or specified cardiovascular risk factors

INTERVENTION(S)

Non-oral HT (e.g., transdermal or intranasal) compared with oral HT or no treatment/placebo.

MAIN OUTCOME MEASURE(S)

Lipoprotein(a), homocysteine, C-reactive protein (CRP), cell adhesion molecules, markers of endothelial dysfunction, coagulation, and fibrinolysis.

RESULT(S)

Seventy-two studies investigating either transdermal or intranasal administration were included. For non-oral HT, decreases in lipoprotein(a), cell adhesion molecules, and factor VII generally were significant, resistance to activated protein C (APCr) was slightly increased, and other markers including CRP and homocysteine did not change. Compared with oral HT, changes in CRP and APCr were smaller, changes in cell adhesion molecules and some fibrinolytic parameters tended to be smaller, whereas changes in other factors including lipoprotein(a) and homocysteine did not differ.

CONCLUSION(S)

Potentially unfavorable changes seen with oral HT on two important markers, CRP and APCr, are substantially smaller with non-oral HT. Non-oral HT has minor effects on the other cardiovascular risk markers studied. Therefore, compared with oral HT, non-oral HT appears be safer with respect to atherosclerotic and venous thromboembolic disease risk.

Effects of estradiol and estradiol sulfamate on the liver of ovariectomized or ovariectomized and hypophysectomized rats

This study was performed to evaluate and compare the effects of estradiol sulfamate (J995) and estradiol (E2) on the hepatic levels of the estrogen receptor (ER) and its mRNA, in ovariectomized (OVX) and OVX+hypophysectomized (OVXHX) female rats and to study the effects on the liver-derived serum compounds angiotensin I, triglycerides, high-density lipoprotein (HDL) and cholesterol. ER concentrations were determined using ligand-binding assay (LBA) and enzyme immuno assay (EIA), and the mRNA levels using solution hybridization. The rats were treated orally (p.o.) or subcutaneously (s.c.) for 7 days, with treatments initiated 14 days after surgery. No differences were found in ER mRNA levels between J995 and E2 treated rats. The s.c. administered estrogens increased ER levels in OVX rats. Addition of GH+DEX to OVXHX rats restored the ER to levels above those seen in intact rats, whereas simultaneous oral treatment with E2 significantly decreased ER levels again. The s.c. treatment with either J995 or E2 limited the increase caused by addition of GH+DEX. After oral treatment angiotensin I levels were increased by E2, but not by J995, while triglycerides, HDL and cholesterol levels were decreased by oral E2, J995 showing a similar pattern but was less effective. In summary, these results on hepatic ER levels and estrogen dependent compounds produced by the liver showed that J995 has a lower impact on the normal liver functions after oral treatment than E2. Thus, J995 is a very promising substance for development of oral estrogen treatment with reduced hepatic side effects.

Pharmacokinetics and pharmacodynamics of 25-mg estradiol implants in postmenopausal Mexican women

OBJECTIVE

To assess the serum concentrations of estradiol (E2), estrone (E1), gonadotrophins, sex hormone-binding globulin, and lipids, and to determine degree of symptom relief after subcutaneous implantation of 25 mg estradiol in postmenopausal Mexican women.

DESIGN

Fifteen postmenopausal, hysterectomized women participated in an open, observational study. Blood samples were obtained before implantation and at regular intervals during a study period of 24 weeks. Climacteric symptoms were evaluated by means of the Greene climacteric scale. Wilcoxon's test was performed on the paired results of pre-and postimplantation values.

RESULTS

Serum concentrations of E2 obtained after implantation were fairly constant, remaining within the early follicular range for the entire study period of 24 weeks, and were associated with significant symptom relief. A physiological, premenopausal E2:E1 ratio was achieved. No significant metabolic changes occurred. Side effects were estrogenic in nature and no removal of implant was required.

CONCLUSIONS

Subcutaneous implantation of 25 mg estradiol results in physiological, premenopausal estrogen concentrations in most women and is associated with considerable symptom relief without inducing significant adverse metabolic effects.

Effects of postmenopausal hormone replacement therapy on lipid, lipoprotein, and apolipoprotein (a) concentrations: analysis of studies published from 1974-2000

OBJECTIVE

To establish reference estimates of the effects of different hormone replacement therapy (HRT) regimens on lipid and lipoprotein levels.

DESIGN

Review and pooled analysis of prospective studies published up until the year 2000.

SETTING

Clinical trials centers, hospitals, menopause clinics.

PATIENT(S)

Healthy postmenopausal women.

INTERVENTION(S)

Estrogen alone, estrogen plus progestogen, tibolone, or raloxifene in the treatment of menopausal symptoms.

MAIN OUTCOME MEASURE(S)

Serum high- and low-density lipoprotein (HDL and LDL) cholesterol, total cholesterol, triglycerides, and lipoprotein (a).

RESULT(S)

Two-hundred forty-eight studies provided information on the effects of 42 different HRT regimens. All estrogen alone regimens raised HDL cholesterol and lowered LDL and total cholesterol. Oral estrogens raised triglycerides. Transdermal estradiol 17-beta lowered triglycerides. Progestogens had little effect on estrogen-induced reductions in LDL and total cholesterol. Estrogen-induced increases in HDL and triglycerides were opposed according to type of progestogen, in the order from least to greatest effect: dydrogesterone and medrogestone, progesterone, cyproterone acetate, medroxyprogesterone acetate, transdermal norethindrone acetate, norgestrel, and oral norethindrone acetate. Tibolone decreased HDL cholesterol and triglyceride levels. Raloxifene reduced LDL cholesterol levels. In 41 studies of 20 different formulations, HRT generally lowered lipoprotein (a).

CONCLUSION(S)

Route of estrogen administration and type of progestogen determined differential effects of HRT on lipid and lipoprotein levels. Future work will focus on the interpretation of the clinical significance of these changes.

Effects of estradiol and estradiol sulfamate on the uterus of ovariectomized or ovariectomized and hypophysectomized rats

Estradiol sulfamate (J995), estradiol-17beta with a substituted sulfamate group in position 3, has much higher systemic estrogenic activity after oral administration than 17beta-estradiol (E2) due to reduced hepatic metabolism of the drug. The lower dose necessary for achievement of adequate systemic estrogenic effects results in a substantial reduction of otherwise commonly observed hepatic side-effects. This makes J995 a strong candidate as an estrogen suitable for oral administration. The present study was performed to examine and compare the effects of J995 and E2 on the uterus after oral or subcutaneous administration to ovariectomized or ovariectomized+hypophysectomized female rats, in particular on the levels of the estrogen receptor (ER) (alpha+beta), ERalpha mRNA and insulin-like growth factor-I (IGF-I) mRNA. The ER levels were determined using a ligand binding assay and the mRNA levels using solution hybridization. The doses of J995 or E2 were chosen to achieve comparable uterotrophic activity. The rats were treated with hormones for 7 days and the treatment was initiated 14 days after surgery. We conclude that there are no major differences in the uterine response to treatment with J995 or E2 with respect to the effects on ER and ERalpha mRNA levels. The IGF-I mRNA level though, is more affected by J995 than by E2 after 7 days of treatment, indicating a prolonged effect of J995.

Selective oestrogen receptor modifiers (SERMs) and breast cancer therapy

Antioestrogen therapy is currently receiving renewed interest for several reasons. Tamoxifen was introduced in the treatment of metastatic breast cancer more than three decades ago. The drug significantly reduces long term mortality and also reduces the risk of contralateral tumours when administered in early breast cancer. Five years of tamoxifen is now standard in adjuvant endocrine therapy, and the drug is currently being evaluated for breast cancer prevention. Despite this, several aspects regarding the pharmacology of the drug are still unclear, and the scientific rationale for dose selection has recently been challenged. Several novel antioestrogen compounds, called selective oestrogen receptor modifiers (SERMs), express selective oestrogen agonistic or antagonistic properties depending on the organ or test system evaluated. Some of these drugs, like raloxifene, do not seem to promote the development of endometrial cancer, although they still have selected oestrogen-like beneficial effects. This paper reviews the pharmacologic and the pharmacokinetic aspects of the different SERMs with particular emphasis on their potential use in therapy and prevention of breast cancer.

Absorption and bioavailability of oestradiol from a gel, a patch and a tablet

OBJECTIVES

To compare oestradiol and oestrone concentrations and bioavailability after a single dose and at a steady state during oral oestradiol valerate, transdermal oestradiol gel and transdermal oestradiol patch treatments.

METHODS

Two open, randomised, cross-over studies were conducted. In the first study, 12 healthy postmenopausal women received 1.5 mg oestradiol as a transdermal gel or a 2 mg oestradiol valerate tablet daily for 14 days. In the second study, 15 postmenopausal women were treated for 18 days with 1.5 mg oestradiol gel or a transdermal patch releasing oestradiol 50 microg/24 h (replaced every 72 h). Venous blood samples for serum oestradiol and oestrone measurements with RIA were taken until 24 or 72 h after the first and last doses.

RESULTS

The tablet and the transdermal gel yielded similar serum oestradiol profiles with a peak concentration 4-5 h after administration. The patch resulted in relatively stable oestradiol levels during the mid third of the wearing time whereas much lower levels were observed in the beginning and towards the end. There was no difference in the fluctuation between the peak and trough oestradiol levels between the gel (56 or 67%) and the tablet (54%) while the fluctuation was greater with the patch (89%). The bioavailability of oestradiol from the gel was 61% as compared with the tablet and 109% as compared with the patch. The gel was not bioequivalent with the tablet or the patch.

CONCLUSIONS

The doses used of the transdermal gel and the patch roughly corresponded to each other with regard to the amount of oestradiol absorbed whereas the bioavailability from the tablet was significantly higher than from the gel. The lack of bioequivalence, the different serum oestradiol profiles and the large intersubject variability suggest that individual dose adjustments may be needed when changing administration form.

New developments in topical estrogen therapy

OBJECTIVE

To review new developments in transdermal E2 therapy in postmenopausal women.

DESIGN

A bibliographic search (Medline) of the medical literature from 1966 through 1995 was used to identify new studies evaluating transdermal E2.

PATIENT(S)

Menopausal and postmenopausal women.

RESULT(S)

Like oral estrogen, transdermal E2 relieves menopausal symptoms, reverses urogenital atrophy, and conserves bone economy. Initial studies have demonstrated beneficial effects of transdermal E2 on cardiovascular function. Quality of life, patient satisfaction, and compliance also improve with transdermal E2. Advances in transdermal delivery continue to emerge, including low-dose systems and patches that maintain serum E2 levels for a full 7-day period.

CONCLUSION(S)

New developments in transdermal administration have the potential to increase the number of postmenopausal women who accept and are compliant with long-term estrogen replacement therapy.

Associations between circulating components of the renin-angiotensin-aldosterone system and left ventricular mass

OBJECTIVE

Cardiac growth may be modulated in part by the trophic effects of neurohormones. The aim of the present study was to investigate the relation between the basal activity of the renin-angiotensin-aldosterone system and left ventricular mass.

DESIGN

A population based sample of 615 middle-age subjects was studied by standardised echocardiography; anthropometric measurements; and biochemical quantification of renin, pro-renin, angiotensinogen, angiotensin converting enzyme (ACE), and aldosterone.

RESULTS

Echocardiographic left ventricular mass index correlated significantly with arterial blood pressure, age, and body mass index. In addition, in men ACE activity was significantly related to left ventricular mass index in univariate (P = 0.0007) and multivariate analyses (P = 0.008). Men with left ventricular hypertrophy presented with significantly higher serum ACE concentrations than those with normal left ventricular mass index (P = 0.002). In both men and women serum aldosterone was strongly related to septal and posterior wall thickness. Furthermore, in women serum aldosterone was positively and independently associated with left ventricular mass index (P = 0.0001). This effect was most prominent in hypertensive women. Finally, women with left ventricular hypertrophy presented with significantly higher serum aldosterone (P = 0.01). No significant associations with left ventricular mass index were observed for angiotensinogen, renin, or pro-renin.

CONCLUSIONS

The data suggest that the variability of serum ACE or aldosterone, as occurred in this large population based sample, may contribute to the modulation of left ventricular mass.

Percutaneous and transdermal oestrogen replacement therapy

The benefits of oestrogen replacement therapy (ERT) have been widely recognized. However, among the drawbacks ascribed to ERT, metabolic disturbances have been observed, particularly after oral administration of oestrogens. Therefore, other routes of delivering oestrogens have been developed. The advantages of delivering drugs through the skin for systemic therapy have been widely recognized and represent a growing sector in drug development. Transdermal delivery of steroids is also a rapidly expanding field and in various clinical situations where hormonal replacement therapy is needed this route of administration is a real breakthrough, considering the relative toxicity of some steroids when given orally. Percutaneous application of steroids has been proven successful in various disorders. Various occlusive transdermal systems have also been designed, all of them aimed at achieving a constant release rate of the molecules contained in their reservoir through the intact skin. The skin itself, and especially the outermost layer, the stratum corneum, can play the role of a reservoir and a rate-controlling membrane. In the field of reproductive hormones, so far, oestradiol, progesterone and testosterone have been demonstrated to be good candidates for transdermal delivery. The effectiveness and the acceptability of transdermal delivery of oestradiol in postmenopausal women have been demonstrated. All the beneficial effects of oestrogen therapy can be achieved through skin delivery, e.g. symptoms relief as well as osteoporosis prevention.

Effects of sex steroids on serum lipids and lipoproteins

Cardiovascular disease is the leading cause of death in women but manifests itself primarily in the postmenopausal years. Menopause appears to increase the cardiovascular risk, at least when surgically induced, whereas the effects of the natural menopause are still a matter of debate. Why postmenopausal women apparently lose their natural cardioprotection is not established, but oestrogen deficiency seems to play an important role. Loss of ovarian hormone production at the menopause significantly alters serum lipids and lipoproteins, giving rise to more atherogenic lipid profiles throughout the postmenopausal years, and these changes may in part be responsible for the alleged cardiovascular risk. Postmenopausal hormone replacement therapy, using oral unopposed oestrogens, induces potential favourable effects on lipids and lipoproteins, and epidemiological evidence has established that the risk of cardiovascular mortality is reduced by 40-60% in women receiving postmenopausal oestrogen therapy. Part of this reduction seems to be explained by changes in lipids and lipoproteins. Parenteral administration of oestrogens induces comparable, although less pronounced effects on lipids and lipoproteins, and the possible cardioprotective role of parenteral administration remains obscure. The addition of progestogens to postmenopausal oestrogen therapy is essential for endometrial protection, but progestogens apparently antagonize some of the actions of oestrogens on lipid metabolism. However, the type, the dose, the duration and the route of administration, as well as the potency balance between the oestrogen and the progestogen employed, are important determinants for the ultimate effect on lipid metabolism. With the use of cyclic administration and the lowest possible doses of progestogens, the oestrogenic actions on lipids and lipoproteins can be largely preserved, but the cardioprotective potential of combined oestrogen-progestogen therapy is as yet unknown.

Cyclic hormonal replacement therapy after the menopause: transdermal versus oral treatment

In an open, randomized, comparative, between-patient trial, 45 postmenopausal women were treated for 4 months with cyclical transdermal oestradiol 0.05 mg per day or oral conjugated equine oestrogens 0.625 mg per day, in both cases, plus, medroxyprogesterone acetate 10 mg per day on the last 8 days of each cycle. Similar relief from postmenopausal symptoms was obtained with both treatments. Post-treatment histological evaluation of the endometrium did not reveal neoplastic or hyperplastic change in any patient. Early follicular-phase plasma oestradiol levels were observed only after transdermal oestradiol. There was a significant reduction in serum total cholesterol and LDL cholesterol in both treatment groups, with no difference between treatments, whereas serum triglyceride levels were decreased only by transdermal oestradiol. Plasma calcium and phosphorus fell significantly and serum intact parathyroid hormone rose significantly, with no difference between the therapies. No significant changes were observed in clotting factors. Transdermal oestradiol appears to be an effective and safe hormonal replacement therapy, and this route of administration may be responsible for the more useful action of the drug on serum lipids and plasma oestradiol levels.

Comparative metabolic study of percutaneous versus oral micronized 17 beta-oestradiol in replacement therapy

The aim of this study was to compare the metabolic effects of two presentations of 17 beta-oestradiol (E2) which are of recognized effectiveness in the prevention of post-menopausal bone loss, one being administered via the oral and the other via the percutaneous route. During this prospective, randomized study, 32 patients were treated for 2 mth with either 2 mg/day of oral micronized E2 (n = 16) or 1.5-3 mg/day of percutaneous E2 (n = 16). Both regimens proved efficacious, since significant increases in oestrone (E1) and E2 concentrations ranging up to mid-follicular values were observed. In the percutaneous-treatment group we noted a significant decrease in triglycerides (TG), without any significant changes in high-density lipoprotein cholesterol (HDL-C) or low-density lipoprotein cholesterol (LDL-C). In the oral-treatment group, we saw no significant increase in HDL-C, although significant increases were observed in body weight, TG, plasma renin substrate (PRS) and sex-hormone-binding globulin (SHBG) as well as significant decreases in antithrombin III (AT III) activity and antigen. All of these metabolic variations led us to the conclusion that oral E2 at the dose established as effective in preventing post-menopausal osteoporosis may, even when micronized, alter certain metabolic and haemostatic parameters in a population characterized by increases in cardiovascular risk factors and morbidity. Oral oestrogen replacement therapy should therefore continue to be used only in carefully selected patients and be strictly followed up by systematic checks on a series of metabolic criteria.

Oestrogen replacement therapy and cardiovascular disease in post-menopausal women. A review

The possible role played by oestrogens in modifying the occurrence of ischaemic heart disease (IHD) in particular and cardiovascular disease (CVD) in general in post-menopausal women has long been controversial. Analysis of the literature reveals a difference between the findings of epidemiological studies published before 1980 and those published more recently. In the former, it was reported that the risk in women using oestrogen replacement therapy (ERT) either remained unchanged or increased in relation to that in non-users. In the latter, the trend changed and ERT was shown to have a definite protective effect. These contradictory results might be explained by a change in prescribing habits, involving the use of lower oestrogen doses and the selection of women with no CVD risk factors as recipients of long-term ERT. The protective effects of ERT have been attributed to metabolic changes induced by oestrogens, namely the increase in high density lipoprotein (HDL) cholesterol observed after oral therapy. Recently, long-term studies using non-oral oestrogens delivered either by implant, or the percutaneous or transdermal routes have indicated the same favourable changes in lipid profiles as seen with oral ERT, provided follow-up is maintained for at least 6 mth. Factors other than lipids that are involved in CVD should also be evaluated in order to clarify the mechanism via which ERT affords cardiovascular protection in post-menopausal women.

Estrogen replacement and cardiovascular disease: serum lipids and blood pressure effects

Coronary heart disease, a major cause of morbidity and death, is the leading cause of death in older women, with an incidence that approaches that in men of comparable age. Estrogen favorably alters lipid metabolism and should therefore diminish the risk for coronary heart disease in estrogen users. Epidemiologic data from case-control and prospective cohort studies have suggested that estrogen use may confer protection from cardiovascular disease and decrease all-cause mortality rates in postmenopausal women. Because the age-adjusted mortality rate due to heart disease among American women is approximately four times the combined mortality rate due to endometrial and breast cancers, even modest changes in the risk of fatal heart disease after estrogen use would dramatically impact the overall risk-benefit equation.

Estrogen replacement therapy: indications, contraindications, and agent selection

Three groups of indications exist for postmenopausal estrogen use: relief of symptoms related to estrogen deficiency, osteoporosis prophylaxis and treatment, and cardioprotection. Estrogen replacement therapy enhances a woman's sense of well-being and reduces the morbidity, mortality, and health care costs associated with osteoporosis and atherosclerotic heart disease. There are a few absolute contraindications to estrogen replacement therapy. Many estrogen preparations are currently available in the United States. Establishing equivalencies among the different preparations is complicated by the many physiologic and pharmacologic effects of estrogens and the variety of treatment end points used. Most estrogens have the same biologic effect provided equivalent blood levels are achieved. Estrogen replacement therapy has proved beneficial to selected postmenopausal women.

Oestrogen concentrations in plasma, endometrium, myometrium and vagina of postmenopausal women, and effects of vaginal oestriol (E3) and oestradiol (E2) applications

Oestradiol (E2), oestriol (E3) and oestrone (E1) levels were measured in plasma and endometrium, myometrium and vagina of 29 postmenopausal women who underwent hysterectomy. The influence of vaginal E3, compared to vaginal E2 therapy at a dose one-tenth that of E3 on the basal steroid levels was examined. We found (1) no correlation between basal tissue and plasma concentrations of the oestrogens in untreated postmenopausal women, however, after vaginal E3 therapy we did find a positive correlation between them, (2) E2 to be the oestrogen in the highest basal concentration in endometrium and myometrium as well as in the vagina, (3) higher basal concentrations of all three oestrogens in endometrium compared to myometrium and vagina, (4) a long term (at least 12 h) elevation of the plasma and tissue E3 concentrations after vaginal E3 therapy (0.5 mg per day), (5) no significant changes of the plasma and tissue E2 concentrations after 0.05 mg per day vaginal E2 therapy, measured 12 h after the last application and (6) no signs of a difference between vagina and uterus in uptake and retention of E3 or E2. In conclusion, there was no difference on this level of mechanism of action in vagina and uterus which can account for the supposed vaginotrophicity and non-uterotrophicity observed with E3 but not E2.

Testosterone-estradiol binding globulin (TeBG) in hirsute patients treated with cyproterone acetate (CPA) and percutaneous estradiol

Testosterone-estradiol binding globulin (TeBG) was studied in 50 hirsute women, before and after 6-month treatment with cyproterone acetate (CPA). 50 mg CPA was administered orally from the 5th to the 25th day of the menstrual cycle and combined with 3 mg 17 beta-estradiol (E2) administered percutaneously from days 16-25 of the cycle. TeBG was evaluated by a filter assay measuring [3H]-DHT binding capacity. Before treatment, the mean plasma TeBG level was 40 +/- 12 nM in hirsute patients, which is significantly lower than TeBG value in normal women (60 +/- 9 nM, n = 20, P less than 0.01) and intermediate between normal women and normal men (30 +/- 8 nM, n = 20). After a 6-month treatment, TeBG strikingly decreased to 22 +/- 8 nM, which is significantly lower than pretreatment values (P less than 0.01) and even less than TeBG level in normal men. Parallel TeBG assay by immunoelectrodiffusion in 8 of these hirsute patients provided similar results. With this treatment, plasma testosterone and delta 4-androstenedione, measured between the 20th and 25th days of the cycle, decreased from 68 +/- 21 to 25 +/- 8 ng/dl, and 210 +/- 95 to 98 +/- 31 ng/dl respectively. Plasma estradiol decreased from 150 +/- 62 pg/ml to 75 +/- 25 pg/ml. In contrast, urinary 3 alpha-androstanediol glucuronide remained high: 112 +/- 51 and 123 +/- 55 micrograms/24 h respectively before and with CPA treatment. Three mechanisms have been proposed to explain TeBG decrease under CPA + E2perc. treatment (1) relative competition of CPA with labelled DHT in the TeBG-binding capacity assay, (2) relative hypoestrogenism with this treatment, (3) a progestagen or even a partial agonistic androgen effect of CPA on TeBG synthesis in the liver. The third mechanism appears to be predominant. In any case. TeBG decrease combined with the partial enzymatic induction effect of CPA on the liver contributes to the increase in the metabolic clearance rate of T and the high urinary Adiol levels previously reported with CPA treatment.

On the regulation of sex-hormone-binding globulin--a challenge of an old dogma and outlines of an alternative mechanism

In this review, the different factors known to affect SHBG levels are discussed with respect to their possible significance in the physiological regulation of this protein: Sex steroids, puberty, nutritional status, thyroid hormones and liver disease. It is concluded that the serum levels of SHBG are related to general metabolic factors, nutritional status, growth and ageing than to the estrogen/androgen balance. The authors suggest that SHBG is regulated primarily by growth hormone, somatomedin-C and possibly other growth factors. Growth hormone may promote SHBG synthesis in the liver while somatomedin-C may stimulate its extravasation and uptake in target tissues. It is suggested that sex steroids merely have an indirect, modulating influence.

Estrogen therapy and liver function--metabolic effects of oral and parenteral administration

Oral estrogen therapy for prostatic cancer is clinically effective but also accompanied by severe cardiovascular side effects. Hypertension, venous thromboembolism, and other cardiovascular disorders are associated with alterations in liver metabolism. The impact of exogenous estrogens on the liver is dependent on the route of administration and the type and dose of estrogen. Oral administration of synthetic estrogens has profound effects on liver-derived plasma proteins, coagulation factors, lipoproteins, and triglycerides, whereas parenteral administration of native estradiol has very little influence on these aspects of liver function.

Stimulation of breast cancer cells in vitro by the environmental estrogen enterolactone and the phytoestrogen equol

The phenolic lignans enterolactone and enterodiol appear periodically in women's urine, dependent upon synthesis from plant-derived lignans by the intestinal microflora. The phytoestrogen equol is also present in women's urine, and is also derived from a vegetarian diet. Antiestrogenic or antiproliferative actions of these compounds have been postulated and related to the observation that there is a reduced incidence of breast cancer associated with diet. We evaluated the estrogenic and antiestrogenic activity of these compounds using four sensitive assays in tissue culture, including the use of human breast cancer cell lines T47D and MCF-7. Unexpectedly, we found that enterolactone and enterodiol, as well as equol, are weak estrogens, and that enterolactone and equol could stimulate the growth of estrogen-dependent breast cancer cell lines. We suggest that these environmental agents can promote the growth of breast cancer, particularly hormone-dependent metastases that may be located near the gut or in the mesenteries or liver, where the concentration of these intestinally produced compounds would be highest. Treatment with an antiestrogen such as tamoxifen blocks the estrogenic activity of these compounds. In the absence of treatment with an antiestrogen such as tamoxifen, hormonal therapy to block steroidal estrogen synthesis in a patient with breast cancer could conceivably be circumvented by a vegeterian diet rich in the precursors to estrogenic compounds such as enterolactone and equol.

Climacteric symptoms after oral and percutaneous hormone replacement therapy

One hundred and ten (110) healthy early post-menopausal women with mild subjective vasomotor symptoms (mean Kupperman index score 11) participated in a long-term, double-blind, placebo-controlled therapeutic trial. The effects of 2 hormone regimens were evaluated. Group I received percutaneous oestrogen therapy for 2 yr, opposed by oral micronized progesterone (200 mg) during the second year, while Group II received oral 17 beta-oestradiol valerate together with cyproterone acetate (CPA). The serum oestrogen concentrations differed markedly in the 2 treatment groups. In Group I the serum/oestrone/oestradiol ratio was 1 (comparable to the pre-menopausal value), but in group II the ratio was greater than 5. Despite the difference in the serum oestradiol and oestrone concentrations, the mean symptom scores were rapidly and similarly reduced in both treatment groups (P less than 0.001). They remained low throughout the study and were not significantly different from pre-menopausal values.

The long-term effect of oral and percutaneous estradiol on plasma renin substrate and blood pressure

The long-term effect of percutaneous and oral estrogen replacement therapy on blood pressure, plasma renin substrate, and serum estrogens was examined in a 2 year placebo-controlled study with 110 early postmenopausal women. The women were allocated to four treatment groups: (1) oral cyclical combination of 2 mg estradiol valerate and cyproterone acetate, (2) oral placebo, (3) percutaneous 17 beta-estradiol, supplemented by 200 mg oral progesterone during the second year, or (4) percutaneous placebo cream. Systolic and diastolic blood pressure remained unchanged in both hormone treatment groups, whereas the diastolic blood pressure tended to increase in both placebo groups. Plasma renin substrate increased during oral treatment with estradiol, but remained unchanged with percutaneous estradiol. No correlation was found between blood pressure and plasma renin substrate. During percutaneous administration of estradiol, the serum concentrations of estrone and estradiol continued to rise after 3 months and reached a plateau at 6 months of therapy. Serum estrone but not estradiol showed the same pattern during oral estradiol therapy. No further changes in any of the measured variables were observed in the women treated with percutaneous estradiol after addition of cyclical oral progesterone. We conclude that both oral and percutaneous treatment with estradiol may provide protection against the age-related increase in diastolic blood pressure observed in early postmenopausal women, and that the metabolic steady state is not attained until after 3 months of estradiol therapy.

Controversies concerning the safety of estrogen replacement therapy

Unopposed estrogen replacement is known to cause endometrial carcinoma in a small percentage of postmenopausal women, but the effects on ovarian and breast tissue remain uncertain. The increased risk of endometrial carcinoma seems to be related to both the dosage and duration of unopposed estrogen treatment. Until very recently, the morbidity and costs that result from the need for endometrial biopsy because of abnormal bleeding and from the need for hysterectomy due to hyperplasia have been ignored, but recent data suggest that they are likely to be considerable. Progestogens are known to protect against endometrial hyperstimulation, but the optimal duration of therapy each month and the maximally protective agent and dose remain to be determined. Estrogen replacement therapy may reduce the risk of arterial disease; however, the comparative effects of the various preparations, as well as their respective mechanisms of action, must be subjected to further study.

Effect of dietary components, including lignans and phytoestrogens, on enterohepatic circulation and liver metabolism of estrogens and on sex hormone binding globulin (SHBG)

A brief account of our present knowledge on the enterohepatic metabolism of estrogens and on the origin, metabolism and biological effects of mammalian lignans and phytoestrogens is undertaken. Furthermore, recently published results on the effects of dietary fiber, fat and carbohydrates on estrogen metabolism are reviewed. New preliminary results are presented on quantitative assays of lignans and phytoestrogens in urine of women belonging to various dietary and population groups and in a group of chimpanzees. The highest values of lignans and phytoestrogens were found in the non-human primates, and in macrobiotic, lactovegetarian and Japanese women, all groups considered having a low risk for the development of breast and other hormone-dependent cancer. New results on correlations between intake of various fibers, lignan and phytoestrogen excretion and plasma levels of estrogens, free testosterone and SHBG in women are presented. There is a significant positive correlation between the intake of fiber and urinary excretion of lignans and phytoestrogens, and the concentration of plasma SHBG. Fiber intake and urinary excretion of lignans and equol correlated negatively with plasma percentage free estradiol. Enterolactone excretion correlated negatively with plasma free testosterone. It is concluded that dietary macro- and micronutrients seem to play an important role in estrogen metabolism.

Steroid-sensitive proteins, growth hormone and somatomedin C in prostatic cancer: effects of parenteral and oral estrogen therapy

The effects of parenteral and parenteral plus oral estrogen therapy on the serum levels of sex hormone binding globulin (SHBG), pregnancy-associated alpha 2-macroglobulin (alpha 2-PAG), growth hormone (GH), and somatomedin C (SmC) were studied in 26 patients with prostatic cancer. Intramuscular polyestradiol phosphate treatment, yielding a mean serum level of estradiol-17 beta of 1,446 pM and a mean testosterone level of 4.5 nM, had no significant effects on alpha 2-PAG, GH, and SmC and increased SHBG levels only marginally. Combined treatment with intramuscular polyestradiol phosphate and oral ethinyl estradiol greatly increased SHBG and alpha 2-PAG levels and caused elevated GH and decreased SmC levels. The route of estrogen administration is probably of major importance for the hormonal effects on hepatic activity as reflected by SHBG and alpha 2-PAG levels. Bypassing the portal circulation might be advantageous with respect to liver-related side effects of estrogen therapy. GH and SmC might act as mediators of estrogen effects on the human liver.