Effect of norethisterone acetate on estrogen metabolism in postmenopausal women.

Dominance of estradiol metabolism at the D-ring over the A-ring metabolism may play a role in the pathophysiology of human breast carcinogenesis. Currently, the influence of progestins on breast cancer risk is debated when added to postmenopausal estradiol replacement therapy. However, nothing is known about the action of progestins on estradiol metabolism. Therefore, the effect of oral and transdermal estradiol/norethisterone acetate (NETA) was investigated on the ratio of the main D-ring metabolite 16alpha-hydroxyestrone (16-OHE1) to the main Aring metabolite 2-hydroxyestrone (2-OHE1). The ratio of 16-OHE1 to 2-OHE1 after transdermal hormone replacement therapy (HRT) was 0.43 before treatment, 0.35 after estradiol and 0.52 after estradiol + NETA. The ratio after oral HRTwas 0.94 before treatment, 0.86 after estradiol and 2.30 after estradiol + NETA. Because of the high variations, no statistical significance could be calculated. Since there was a tendency to an increase after oral estradiol + NETA treatment, the individual patient profiles were examined. Here, three patients in the oral treatment group showed a significant increase of the ratio after the estradiol/NETA phase. In conclusion, transdermal NETA in HRT did not elicit any change in estrogen metabolism after 2 weeks' treatment. However, oral NETA may in some cases have an impact on estradiol metabolism which should be further evaluated.     

Effect of estrogen on tendon collagen synthesis, tendon structural characteristics, and biomechanical properties in postmenopausal women

The knowledge about the effect of estradiol on tendon connective tissue is limited. Therefore, we studied the influence of estradiol on tendon synthesis, structure, and biomechanical properties in postmenopausal women. Nonusers (control, n = 10) or habitual users of oral estradiol replacement therapy (ERT, n = 10) were studied at rest and in response to one-legged resistance exercise. Synthesis of tendon collagen was determined by stable isotope incorporation [fractional synthesis rate (FSR)] and microdialysis technique (NH(2)-terminal propeptide of type I collagen synthesis). Tendon area and fibril characteristics were determined by MRI and transmission electron microscopy, whereas tendon biomechanical properties were measured during isometric maximal voluntary contraction by ultrasound recording. Tendon FSR was markedly higher in ERT users (P < 0.001), whereas no group difference was seen in tendon NH(2)-terminal propeptide of type I collagen synthesis (P = 0.32). In ERT users, positive correlations between serum estradiol (s-estradiol) and tendon synthesis were observed, whereas change in tendon synthesis from rest to exercise was negatively correlated to s-estradiol. Tendon area, fibril density, fibril volume fraction, and fibril mean area did not differ between groups. However, the percentage of medium-sized fibrils was higher in ERT users (P < 0.05), whereas the percentage of large fibrils tended to be greater in control (P = 0.10). A lower Young's modulus (GPa/%) was found in ERT users (P < 0.05). In conclusion, estradiol administration was associated with higher tendon FSR and a higher relative number of smaller fibrils. Whereas this indicates stimulated collagen turnover in the resting state, collagen responses to exercise were negatively associated with s-estradiol. These results indicate a pivotal role for estradiol in maintaining homeostasis of female connective tissue.     

Evaluation of high-dose estrogen and high-dose estrogen plus methyltestosterone treatment on cognitive task performance in postmenopausal women

OBJECTIVES: To investigate the cognitive effects of high-dose oral estrogen alone or in combination with oral methyltestosterone in postmenopausal women. METHODS: Participants were tested with a randomized, double-blind design on the Identical Pictures, Cube Comparisons, Building Memory and Shape Memory tasks before and after 4 months of hormone treatment. RESULTS: Women receiving estrogen and methyltestosterone maintained a steady level of performance on the Building Memory task, whereas those receiving estrogen alone showed a decrease in performance. CONCLUSIONS: These results indicate that the addition of testosterone to high-dose estrogen replacement exerts a protective effect on memory performance in postmenopausal women.     

The estrogen receptor alpha gene determines serum androstenedione levels in postmenopausal women

Estrogen receptors (ER) are expressed not only in the reproductive system and ovaries but also in some other tissues, including the adrenal gland. The purpose of this study was to assess the association between the estrogen receptor (ER) alpha gene polymorphisms XbaI and PvuII and circulating levels of androstenedione, a precursor of sex-steroids synthetized in the ovary and adrenal. After adjustment for years since menopause, body mass, and dehydroepiandrosterone (DHEA) levels, a highly significant relationship was demonstrated between androstenedione and XbaI or PvuII polymorphisms, the highest levels of the hormone being found in the xx and pp genotypes (P<0.05 as compared to XX or PP, ANCOVA followed by least significant difference (LSD) multiple comparisons). This suggests that the ER genotype may determine the function of the sex-steroid system not only at the receptor level but also at the level of hormone synthesis. The pathogenetic role of this association in diseases related to menopause, such as osteoporosis, remains to be determined.     

Regulation of collagenolytic cysteine protease synthesis by estrogen in osteoclasts

In ovariectomized (Ovx) mice, collagenolytic cysteine protease (CCP) activity in calvaria significantly increased 7 days after ovariectomy and was about 50% of that observed in sham-operated (Sham) mice 3 weeks later. In Ovx mice, subcutaneously (s.c.) administered estradiol-17beta (E2) (10 microg/kg) for 2 weeks led to a decrease in CCP activity in calvaria to the level observed in Sham mice. In Ovx mice, though the amount of cathepsin L increased more than that of cathepsin K, cathepsin K and cathepsin L content increased by 200-400% compared with the Sham mice; cathepsin K was detected in larger amounts than cathepsin L in calvaria from both Sham and Ovx mice. The amounts of cathepsin K and cathepsin L in Ovx mice were reduced to the values seen with Sham mice after administration (s.c.) of E2 (10 microg/kg) for 2 weeks. In mouse calvarial organ culture, the increase of CCP activity and release of hydroxyproline, an indicator of degradation of type-I collagen, in the presence of 1alpha,25-(OH)(2)D(3), parathyroid hormone, interleukin (IL)-1alpha, IL-6, or tumor necrosis factor-alpha was suppressed by E2 (10(-9)-10(-7) M). In all cases, secretion of both cathepsin K and cathepsin L were suppressed by E2. In osteoclasts, expression of cathepsin K and cathepsin L was suppressed by E2 at the mRNA level. Cathepsin B was detected faintly or not at all. These results suggest that synthesis of cathepsin K and cathepsin L was negatively regulated by E2 at the mRNA level. In Ovx mice, deficiency of E2 resulted in an augmentation of cathepsin K and cathepsin L synthesis, and the cathepsins might share roles in bone resorption in vivo.     

Regulation of exercise carbohydrate metabolism by estrogen and progesterone in women

To assess the roles of endogenous estrogen (E2) and progesterone (P4) in regulating exercise carbohydrate use, we used pharmacological suppression and replacement to create three distinct hormonal environments: baseline (B), with E2 and P4 low; estrogen only (E), with E2 high and P4 low; and estrogen/progesterone (E + P), with E2 and P4 high. Blood glucose uptake (R(d)), total carbohydrate oxidation (CHO(ox)), and estimated muscle glycogen utilization (EMGU) were assessed during 60 min of submaximal exercise by use of stable isotope dilution and indirect calorimetry in eight eumenorrheic women. Compared with B (1.26 +/- 0.04 g/min) and E + P (1.27 +/- 0.04 g/min), CHO(ox) was lower with E (1.05 +/- 0.02 g/min). Glucose R(d) tended to be lower with E and E + P relative to B. EMGU was 25% lower with E than with B or E + P. Plasma free fatty acids (FFA) were inversely related to EMGU (r(2) = 0.49). The data suggest that estrogen lowers CHO(ox) by reducing EMGU and glucose R(d). Progesterone increases EMGU but not glucose R(d). The opposing actions of E(2) and P(4) on EMGU may be mediated by their impact on FFA availability or vice versa.     

Inhibition of oestrogen synthesis in postmenopausal women with breast cancer.

The effectiveness in reducing oestrogen exposure, of an aromatase inhibitor, and a sulphatase inhibitor, as measured by in vivo studies in breast cancer patients, has been investigated. 4-Hydroxyandrostenedione (4HA) was shown to diminish plasma oestrogen levels, to inhibit peripheral and local aromatization and to cause a concomitant decrease in the activity of DNA-polymerase-alpha, measured as an indicator of cellular proliferation. The source of oestrone sulphate in breast tissues was examined, and it was shown that the tissue content of this conjugate derived from circulating oestrone, but no evidence could be found for the direct accumulation of conjugate from the plasma. Administration of Danazol was found to cause a fall in plasma oestrone levels, and to diminish the conversion ratio of oestrone sulphate to oestrone in some patients. It also inhibited tissue sulphatase activity. Although it is concluded that this drug is only a weak sulphatase inhibitor, these observations indicate the potential value of developing more efficient sulphatase inhibitors. Enzyme inhibition is now a proven effective treatment for breast cancer and the development of more efficient inhibitors is an important objective.     

Prevalence of estrogen receptor alpha PvuII and XbaI polymorphism in population of Polish postmenopausal women

Numerous data indicate that polymorphism of estrogen receptor alpha (ERalpha) may predict lipid levels, lipid response to hormone replacement therapy (HRT), myocardial infarction risk, bone fracture risk, bone mineral density (BMD) and changes in BMD over time. In this study we aimed to evaluate distribution of ERalpha PvuII and XbaI genotypes in population of Polish postmenopausal women qualified to different protocols of HRT. Subject of the study were 64 consecutive postmenopausal women aged from 45 to 65 years (mean 56.6) assigned to HRT. ERalpha PvuII and XbaI polymorphism was determined by PCR-restriction fragment length polymorphism (RFLP). The absence of PvuII and XbaI restriction sites were indicated by "P" and "X" and presence by "p" and "x", respectively. PvuII genotype was distributed as follows: PP 17.2% (n=11), Pp 50% (n=32), pp 32.83% (n=21). Frequency of XbaI genotype was: XX 6.25% (n=4), Xx 34.4% (n=22), xx 59.4% (n=38). Four haplotypes with following frequencies were recognized: PX 17.3%, px 47.4%, Px 24.4% and pX 10.9%. Prevalence of estrogen receptor alpha PvuII and XbaI polymorphisms in Polish women is similar to previously studied population.     

The localization of estrogen receptor alpha and its function in the ovaries of postmenopausal women

The localization of estrogen receptor alpha (ERalpha) in the ovaries of postmenopausal women is a very up-to-date topic in the aspect of using estrogens therapy in the clinical situations of different type. In ovaries of reproductive age women ERalpha is present in ovary stroma, theca and granulosa cells, ovary surface epithelium (OSE) and in corpus luteum. The ovaries of postmenopausal women are smaller than those of women at the reproductive age, the division into cortex and medulla gets blurred, the ovaries have no follicles any longer, and the stroma is mainly composed of fibrous connective tissue, corpora albicantia, nerves, and blood and lymphatic vessels. The aim of our study was to investigate the immunolocalization and immunoexpression of ERalpha in the ovaries of postmenopausal women. The study involved 50 postmenopausal women who had their ovaries removed by laparotomy due to non-neoplastic diseases of the uterus. The women were divided into 3 groups (A, B, and C) depending on the time that had passed since the last menstruation. Group A consisted of women who had their last menstruation no more than 5 years earlier, in group B menopause occurred 5 to 10 years earlier, group C was composed of patients who had the last menstruation over 10 years earlier. In all the patients concentrations of follicle stimulating hormone (FSH), luteinizing stimulating hormone (LH), estradiol (E2), testosterone (T), androstendione (A) and dehydroepiandrosterone sulphate (DHEAS) in blood plasma were measured. Ovarian tissue was obtained during surgery. For morphological studies, ovaries were fixed in Bouin;s solution and 4% formalin and embedded in paraffin. Morphological analysis was carried out after hematoxylin-eosin (HE) staining. Comparing to groups A and B, the ovaries in group C contained a small number of corpora albicantia located in the medullary part as well as thinned blood vessels and few lymphatic vessels and nerves. For immunoohistochemical expression of ERalpha paraffin-embedded specimens fixed in 4% buffered formalin were used. The sections were next incubated with monoclonal mouse anti-human ERalpha antibody (N 1575 Dako, Denmark). Immunohistochemical nuclear expression of ERalpha in OSE, in epithelial inclusion cysts, in stroma, and in group A also cytoplasmic expression of ERalpha in luteal and paraluteal cells of disappearing corpus luteum were revealed. Immunohistochemical expression of ERalpha seems to decrease in the ovaries of women after menopause.     

Effects of continuous conjugated estrogen and micronized progesterone therapy upon lipoprotein metabolism in postmenopausal women

The effects of continuously administering both conjugated equine estrogens (CEE) and micronized progesterone (MP) on the concentration, composition, production and catabolism of very low density (VLDL) and low density lipoproteins (LDL) have not previously been reported. The mechanism of the hormonally induced reductions of plasma LDL cholesterol of S(f) 0;-20 (mean 16%, P < 0.005) and LDL apoB (mean 6%, P < 0.025) were investigated by studying the kinetics of VLDL and LDL apolipoprotein (apo) B turnover after injecting autologous (131)I-labeled VLDL and (125)I-labeled LDL into each of the 6 moderately hypercholesterolemic postmenopausal subjects under control conditions and again in the fourth week of a 7-week course of therapy (0.625 mg/d of CEE + 200 mg/d of MP). The combined hormones significantly lowered plasma LDL apoB by increasing the mean fractional catabolic rate of LDL apoB by 20% (0. 32 vs. 0.27 pools/d, P < 0.03). Treatment also induced a significant increase in IDL production (6.3 vs. 3.7 mg/kg/d, P = 0.028). However, this did not result in an increase in LDL production because of an increase in IDL apoB direct catabolism (mean 102%, P = 0.033). VLDL kinetic parameters were unchanged and the concentrations of plasma total triglycerides (TG), VLDL-TG, VLDL-apoB did not rise as often seen with estrogen alone. Plasma HDL-cholesterol rose significantly (P < 0.02). Our major conclusion is that increased fractional catabolism of LDL underlies the LDL-lowering effect of the combined hormones.     

A beneficial effect of estrogen on working memory in postmenopausal women taking hormone replacement therapy

Recent neurophysiological data suggest that the prefrontal cortex (PFC) may be susceptible to modulation by estrogen. In humans, the PFC mediates a number of cognitive processes that contribute to memory function, particularly working memory. The present study examined whether memory tasks that recruit PFC-dependent information processing might exhibit estrogen sensitivity in women. Performance on several memory tasks, including measures of working memory, was evaluated in three groups of postmenopausal women: (1) women who were tested when taking estrogen only (n = 38, M(age) = 55.1 years), (2) women who were tested when taking estrogen and a progestin concurrently (n = 23, M(age) = 55.9 years), and (3) women who were not taking hormone replacement therapy (n = 35, M(age) = 56.0 years). Estrogen users exhibited significantly better performance on a verbal task and on a spatial task, each with a prominent working memory component, but did not differ from nonusers on control tasks involving simple passive recall. These findings are consistent with the hypothesis that estrogen is active within PFC and is capable of influencing functions dependent on this region. The results of this study raise the possibility that estrogen may play a role in maintaining certain frontal lobe functions in women.     

Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal women

A study was done to examine the effects of aluminum, magnesium, and boron on major mineral metabolism in postmenopausal women. This communication describes some of the effects of dietary boron on 12 women between the ages of 48 and 82 housed in a metabolic unit. A boron supplement of 3 mg/day markedly affected several indices of mineral metabolism of seven women consuming a low-magnesium diet and five women consuming a diet adequate in magnesium; the women had consumed a conventional diet supplying about 0.25 mg boron/day for 119 days. Boron supplementation markedly reduced the urinary excretion of calcium and magnesium; the depression seemed more marked when dietary magnesium was low. Boron supplementation depressed the urinary excretion of phosphorus by the low-magnesium, but not by the adequate-magnesium, women. Boron supplementation markedly elevated the serum concentrations of 17 beta-estradiol and testosterone; the elevation seemed more marked when dietary magnesium was low. Neither high dietary aluminum (1000 mg/day) nor an interaction between boron and aluminum affected the variables presented. The findings suggest that supplementation of a low-boron diet with an amount of boron commonly found in diets high in fruits and vegetables induces changes in postmenopausal women consistent with the prevention of calcium loss and bone demineralization.     

The effects of estrogen on indices of skeletal muscle tissue damage after eccentric exercise in postmenopausal women

This study examined if estrogen (E) usage (in the form of hormone replacement therapy [HRT]) has a protective effect on skeletal muscle damage in postmenopausal women. Nine postmenopausal women (age 55.2 +/- 9.9 [mean +/- SD]) performed two exercise sessions at 70% of their maximal heart rate on HRT (E-HI) and without HRT (E-LO; following a 28-45 day HRT washout). All subjects followed a condition order of E-HI then E-LO with at least 42 days between exercise sessions. Serum creatine kinase (CK), perceived delayed onset muscle soreness (DOMS), and maximal quadriceps isometric force (MIF) were taken pre-exercise, 24, 48 and 72-hr post exercise. E-HI and E-LO conditions produced a rise in CK (p < 0.001) after exercise; but CK after E-HI was greater than in E-LO (p < 0.001) at 24 hours and at 48 hours. DOMS was significantly elevated at 24, 48, and 72-hr post each exercise session (p < 0.05). The greatest peak DOMS score occurred during the E-HI condition. MIF was similarly reduced after each exercise session (p < 0.05). These results suggest elevated E does not offer a protective effect to skeletal muscle; however, design limitations (i.e., condition order) confound the present data. Interestingly, an association between peak-CK during the E-LO condition and the number of washout days (r = +0.707, p < 0.05) between conditions existed. This suggests a longer washout period may be necessary to elucidate the actual E effects on skeletal muscle. These findings suggest that more work correcting for the present design limitations is warranted on this topic.     

Codon 325 sequence polymorphism of the estrogen receptor alpha gene and bone mineral density in postmenopausal women

Estrogen receptor alpha (ER alpha) encoding gene is one of the candidate genes to be involved in the development of osteoporosis. Until now correlation between three ER gene polymorphisms (identified with PvuII, XbaI and BstUI) and bone mineral density (BMD) have been investigated. The results of these studies are contradictory. Thus the aim of our work was to search for new, yet unknown, and probably more informative polymorphism(s) of the ER alpha gene. For detection of mutations the whole coding region of the ER alpha gene was screened systematically. In a group of 85 late postmenopausal women all of the eight exons were amplified by polymerase chain reaction (PCR) and fragments were further analyzed by single-stranded conformation polymorphism (SSCP) analysis. Mutations were confirmed by direct DNA sequencing. In the whole coding region of the ER alpha gene two silent mutations in codon 87 and 325, respectively, were found. The silent mutation in codon 85 of exon 1 (GCG-->GCC; A87A) was described previously, as BstUI polymorphism. On the other side, the silent mutation in codon 325 (CCC-->CCG; P325P), located in exon 4, has not been analyzed so far in correlation with BMD. According to the distribution of genotypes CC:CG:GG=49.4:41.2:9.4, we can affirm the existence of genetic polymorphism in codon 325 in our population of late postmenopausal women. The mean femoral neck BMD, but not the lumbar spine BMD, was significantly lower (P=0.029) in the homozygous GG-women with CCG/CCG codon 325 as compared to the homozygous CC-women with the normal codon CCC/CCC. Our results suggest that codon 325 sequence polymorphism of the ER alpha gene might be one of the factors associated with low femoral neck BMD.