Endocrine function of the peri- and postmenopausal ovary

Androgens in premenopausal women and women with premature ovarian insufficiency

Premature ovarian insufficiency (POI) results in both estrogen and testosterone insufficiency. Whether testosterone therapy may be of benefit for women with POI is uncertain. Presently, the only evidence-based indication for testosterone therapy for women is for the treatment of postmenopausal women with low sexual desire with associated personal distress. Consistent with this, available evidence does not support the prescription of testosterone to prevent cardiometabolic disease, bone loss, sarcopenia, or cognitive decline or to improve well-being and low mood in postmenopausal women. Data pertaining to the treatment of women with POI with testosterone are limited. This article reviews androgen physiology in premenopausal women and the impact of POI on circulating androgen concentrations, summarizes findings from observational studies and clinical trials of testosterone therapy in premenopausal women and women with POI, and concludes with recommendations regarding testosterone use in women with POI.

Sex hormones and stroke: Beyond estrogens

Stroke risk and poor stroke outcomes in postmenopausal women have usually beeen attributed to decreased levels of estrogen. However, two lines of evidence suggest that this hormone may not be solely responsible for elevated stroke risk in this population. First, the increased risk for CVD and stroke occurs much earlier than menopause at a time when estrogen levels are not yet reduced. Second, estrogen therapy has not successfully reduced stroke risk in all studies. Other sex hormones may therefore also contribute to stroke risk. Prior to menopause, levels of the gonadotrophin Follicle Stimulating Hormone (FSH) are elevated while levels of the gonadal peptide inhibin are lowered, indicating an overall decrease in ovarian reserve. Similarly, reduced estrogen levels at menopause significantly increase the ratio of androgens to estrogens. In view of the evidence that androgens may be unfavorable for CVD and stroke, this elevated ratio of testosterone to estrogen may also contribute to the postmenopause-associated stroke risk. This review synthesizes evidence from different clinical populations including natural menopause, surgical menopause, women on chemotherapy, and preclinical stroke models to dissect the role of ovarian hormones and stroke risk and outcomes.

Does the degree of endocrine dyscrasia post-reproduction dictate post-reproductive lifespan? Lessons from semelparous and iteroparous species

Post-reproductive lifespan varies greatly among species; human post-reproductive lifespan comprises ~30-50% of their total longevity, while semelparous salmon and dasyurid marsupials post-reproductive lifespan comprises <4% of their total longevity. To examine if the magnitude of hypothalamic-pituitary-gonadal (HPG) axis dyscrasia at the time of reproductive senescence determines post-reproductive lifespan, we examined the difference between pre- and post-reproductive (1) circulating sex hormones and (2) the ratio of sex steroids to gonadotropins (e.g., 17β-estradiol/follicle-stimulating hormone (FSH)), an index of the dysregulation of the HPG axis and the level of dyotic (death) signaling post-reproduction. Animals with a shorter post-reproductive lifespan (<4% total longevity) had a more marked decline in circulating sex steroids and corresponding elevation in gonadotropins compared to animals with a longer post-reproductive lifespan (30-60% total longevity). In semelparous female salmon of short post-reproductive lifespan (1%), these divergent changes in circulating hormone concentration post-reproduction equated to a 711-fold decrease in the ratio of 17β-estradiol/FSH between the reproductive and post-reproductive periods. In contrast, the decrease in the ratio of 17β-estradiol/FSH in iteroparous female mammals with long post-reproductive lifespan was significantly less (1.7-34-fold) post-reproduction. Likewise, in male semelparous salmon, the decrease in the ratio of testosterone/FSH (82-fold) was considerably larger than for iteroparous species (1.3-11-fold). These results suggest that (1) organisms with greater reproductive endocrine dyscrasia more rapidly undergo senescence and die, and (2) the contribution post-reproduction by non-gonadal (and perhaps gonadal) tissues to circulating sex hormones dictates post-reproductive tissue health and longevity. In this way, reproduction and longevity are coupled, with the degree of non-gonadal tissue hormone production dictating the rate of somatic tissue demise post-reproduction and the differences in post-reproductive lifespans between species.

The VCD Mouse Model of Menopause and Perimenopause for the Study of Sex Differences in Cardiovascular Disease and the Metabolic Syndrome

In females, menopause, the cessation of menstrual cycling, is associated with an increase in risk for several diseases such as cardiovascular disease, osteoporosis, diabetes, the metabolic syndrome, and ovarian cancer. The majority of women enter menopause via a gradual reduction of ovarian function over several years (perimenopause) and retain residual ovarian tissue. The VCD mouse model of menopause (ovarian failure in rodents) is a follicle-deplete, ovary-intact animal that more closely approximates the natural human progression through perimenopause and into the postmenopausal stage of life. In this review, we present the physiological parameters of how to use the VCD model and explore the VCD model and its application into the study of postmenopausal disease mechanisms, focusing on recent murine studies of diabetic kidney disease, the metabolic syndrome, and hypertension.

ANG II-induced hypertension in the VCD mouse model of menopause is prevented by estrogen replacement during perimenopause

Premenopausal females are resistant to the development of hypertension, and this protection is lost after the onset of menopause, resulting in a sharp increase in disease onset and severity. However, it is unknown how a fluctuating ovarian hormone environment during the transition from perimenopause to menopause impacts the onset of hypertension, and whether interventions during perimenopause prevent disease onset after menopause. A gradual transition to menopause was induced by repeated daily injections of 4-vinylcyclohexene diepoxide (VCD). ANG II (800 ng·kg(-1)·min(-1)) was infused into perimenopausal and menopausal female mice for 14 days. A separate cohort of mice received 17β-estradiol replacement during perimenopause. ANG II infusion produced significantly higher mean arterial pressure (MAP) in menopausal vs. cycling females, and 17β-estradiol replacement prevented this increase. In contrast, MAP was not significantly different when ANG II was infused into perimenopausal and cycling females, suggesting that female resistance to ANG II-induced hypertension is intact during perimenopause. ANG II infusion caused a significant glomerular hypertrophy, and hypertrophy was not impacted by hormonal status. Expression levels of aquaporin-2 (AQP2), a collecting duct protein, have been suggested to reflect blood pressure. AQP2 protein expression was significantly downregulated in the renal cortex of the ANG II-infused menopause group, where blood pressure was increased. AQP2 expression levels were restored to control levels with 17β-estradiol replacement. This study indicates that the changing hormonal environment in the VCD model of menopause impacts the severity of ANG II-induced hypertension. These data highlight the utility of the ovary-intact VCD model of menopause as a clinically relevant model to investigate the physiological mechanisms of hypertension that occur in women during the transition into menopause.

Midkine, a heparin-binding protein, is increased in the diabetic mouse kidney postmenopause

Estrogen is thought to protect against the development of chronic kidney disease, and menopause increases the development and severity of diabetic kidney disease. In this study, we used streptozotocin (STZ) to induce diabetes in the 4-vinylcyclohexene diepoxide (VCD)-treated mouse model of menopause. DNA microarrays were used to identify gene expression changes in the diabetic kidney postmenopause. An ANOVA model, CARMA, was used to isolate the menopause effect between two groups of diabetic mice, diabetic menopausal (STZ/VCD) and diabetic cycling (STZ). In this diabetic study, 8,864 genes of the possible 15,600 genes on the array were included in the ANOVA; 99 genes were identified as demonstrating a >1.5-fold up- or downregulation between the STZ/VCD and STZ groups. We randomly selected genes for confirmation by real-time PCR; midkine (Mdk), immediate early response gene 3 (IEX-1), mitogen-inducible gene 6 (Mig6), and ubiquitin-specific protease 2 (USP2) were significantly increased in the kidneys of STZ/VCD compared with STZ mice. Western blot analysis confirmed that Mdk and IEX-1 protein abundance was significantly increased in the kidney cortex of STZ/VCD compared with STZ mice. In a separate study, DNA microarrays and CARMA analysis were used to identify the effect of menopause on the nondiabetic kidney; VCD-treated mice were compared with cycling mice. Of the possible 15,600 genes on the array, 9,142 genes were included in the ANOVA; 20 genes were identified as demonstrating a >1.5-fold up- or downregulation; histidine decarboxylase and vanin 1 were among the genes identified as differentially expressed in the postmenopausal nondiabetic kidney. These data expand our understanding of how hormone status correlates with the development of diabetic kidney disease and identify several target genes for further studies.

Loss of ovarian function in the VCD mouse-model of menopause leads to insulin resistance and a rapid progression into the metabolic syndrome

Factors comprising the metabolic syndrome occur with increased incidence in postmenopausal women. To investigate the effects of ovarian failure on the progression of the metabolic syndrome, female B(6)C(3)F(1) mice were treated with 4-vinylcyclohexene diepoxide (VCD) and fed a high-fat (HF) diet for 16 wk. VCD destroys preantral follicles, causing early ovarian failure and is a well-characterized model for the gradual onset of menopause. After 12 wk on a HF diet, VCD-treated mice had developed an impaired glucose tolerance, whereas cycling controls were unaffected [12 wk AUC HF mice 13,455 +/- 643 vs. HF/VCD 17,378 +/- 1140 mg/dl/min, P < 0.05]. After 16 wk on a HF diet, VCD-treated mice had significantly higher fasting insulin levels (HF 5.4 +/- 1.3 vs. HF/VCD 10.1 +/- 1.4 ng/ml, P < 0.05) and were significantly more insulin resistant (HOMA-IR) than cycling controls on a HF diet (HF 56.2 +/- 16.7 vs. HF/VCD 113.1 +/- 19.6 mg/dl x microU/ml, P < 0.05). All mice on a HF diet gained more weight than mice on a standard diet, and weight gain in HF/VCD mice was significantly increased compared with HF cycling controls. Interestingly, even without a HF diet, progression into VCD-induced menopause caused a significant increase in cholesterol and free fatty acids. Furthermore, in mice fed a standard diet (6% fat), insulin resistance developed 4 mo after VCD-induced ovarian failure. Insulin resistance following ovarian failure (menopause) was prevented by estrogen replacement. Studies here demonstrate that ovarian failure (menopause) accelerates progression into the metabolic syndrome and that estrogen replacement prevents the onset of insulin resistance in VCD-treated mice. Thus, the VCD model of menopause provides a physiologically relevant means of studying how sex hormones influence the progression of the metabolic syndrome.

Hysterectomy with preservation of both ovaries does not result in premature ovarian failure

This study investigated ovarian function and adnexial pathology following total abdominal hysterectomy with preservation of both ovaries compared with that in a control group. Data from 29 patients who had undergone total abdominal hysterectomy at age < or =40 years and 42 menopausal patients with no previous ovarian pathology were evaluated retrospectively. The mean (+/- SD) age of menopause was 49.7 +/- 1.5 years in the total abdominal hysterectomy group and 50.1 +/- 1.3 years in the control group; this difference was not statistically significant. The incidences of cyst and hydrosalpinx were 31% and 6.9%, respectively, in the total abdominal hysterectomy group and 44.8% and 0%, respectively, in the control group. The increased incidence of cysts in the total abdominal hysterectomy group was statistically significant. In conclusion, patients who undergo total abdominal hysterectomy without oophorectomy do not experience premature menopause. Preservation of the ovaries may avoid the disadvantages of hormone replacement therapy at the expense of a higher risk of developing adnexial pathology.

Hormonal status affects the progression of STZ-induced diabetes and diabetic renal damage in the VCD mouse model of menopause

Changes in the estrogen/testosterone balance at menopause may negatively influence the development of diabetic kidney disease. Furthermore, recent studies suggest that changes in hormone levels during perimenopause may influence disease development. Injection of 4-vinylcyclohexene diepoxide (VCD) in B(6)C(3)F(1) mice induces gradual ovarian failure, preserving both the perimenopausal (peri-ovarian failure) and menopausal (post-ovarian failure) periods. To address the impact of the transition into menopause on the development of diabetes and diabetic kidney damage, we used streptozotocin (STZ)-induced diabetes in the VCD model of menopause. After 6 wk of STZ-induced diabetes, blood glucose was significantly increased in post-ovarian failure (post-OF) diabetic mice compared with cycling diabetic mice. In peri-ovarian failure (peri-OF) diabetic mice, blood glucose levels trended higher but were not significantly different from cycling diabetic mice, suggesting a continuum of worsening blood glucose across the menopausal transition. Cell proliferation, an early marker of damage in the kidney, was increased in post-OF diabetic mice compared with cycling diabetic mice, as measured by PCNA immunohistochemistry. In post-OF diabetic mice, mRNA abundance of early growth response-1 (Egr-1), collagen-4alpha1, and matrix metalloproteinase-9 were increased and 3beta-hydroxysteroid dehydrogenase 4 (3beta-HSD4) and transforming growth factor-beta(2) (TGF-beta(2)) were decreased compared with cycling diabetic mice. In peri-OF diabetic mice, mRNA abundance of Egr-1 and 3beta-HSD4 were increased, and TGF-beta(2) was decreased compared with cycling diabetic mice. This study highlights the importance and utility of the VCD model of menopause, as it provides a physiologically relevant system for determining the impact of the menopausal transition on diabetes and diabetic kidney damage.

The post-menopausal ovary displays a unique pattern of steroidogenic enzyme expression

BACKGROUND

While menopause results in the loss of cyclic steroid production, evidence exists for persistent, albeit reduced, ovarian androgen production. In order to continue to synthesize ovarian androgens, the steroidogenic enzymes necessary for androgen biosynthesis must be present. Few studies have selectively analysed some of the steroidogenic enzymes present in the post-menopausal ovary (PMO), and a comprehensive study of this matter has never been undertaken.

METHODS

RNA and protein were obtained from PMO, pre-menopausal ovarian stroma, corpora lutea (CL), ovarian follicles, placenta, and myometrium. Oligonucleotide microarray analysis was performed to compare the gene expression profiles of PMO with pre-menopausal ovarian stroma. Real-time RT-PCR was performed for LH/HCG receptor (LHCGR), steroidogenic acute regulatory (StAR), cholesterol side-chain cleavage (CYP11A), 3beta-hydroxysteroid dehydrogenase type I (HSD3B1) and type II (HSD3B2, 3betaHSD), 17a-hydroxylase (CYP17), cytochrome b5 (CytB5), and aromatase (CYP19). Western blot analysis was performed for StAR, CYP11A, CYP17,and 3betaHSD.

RESULTS

The PMO and pre-menopausal ovarian stroma had a similar pattern of steroidogenic enzyme expression. The PMO had persistent, but reduced, levels of LHCGR and most steroidogenic enzymes. CYP19 and HSD3B2 mRNA were greatly reduced in PMO in comparison with CL (50-fold and 2000-fold less respectively). HSD3B2 was not detectable in PMO by western analysis.

CONCLUSIONS

This study supports the idea that the PMO retains some steroidogenic capacity. However, based on steroidogenic enzyme expression, the PMO has a unique pattern of steroidogenic enzyme expression that favors Delta5 steroid formation over Delta4 steroid formation.

Tamoxifen is an estrogen antagonist on gonadotropin secretion and responsiveness of the hypothalamic-pituitary- adrenal axis in female monkeys

The selective estrogen receptor modulator, tamoxifen, effectively slows the progression of estrogen-positive breast cancer and reduces the possibility of this cancer developing in women at high risk. Despite the widespread acceptance of tamoxifen as a therapeutic agent for this disease, its effects on other estrogen-dependent pathways, particularly on neural circuits regulating brain function and peripheral hormone secretion, are poorly understood. The present study, using previously ovariectomized rhesus monkeys, examined the effects of tamoxifen, in both the presence and absence of estradiol replacement, on the reproductive and hypo-thalamic-pituitary-adrenal (HPA) axes. In Experiment 1, monkeys randomly assigned to three groups (n = 8 each) were treated with placebo and either two doses of estradiol, two doses of tamoxifen alone, or two doses of tamoxifen plus high-dose estradiol to assess the effects on negative feedback suppression of luteinizing hormone (LH). Both doses of tamoxifen effectively antagonized the negative feedback efficacy of estradiol on LH secretion. In contrast, neither the low- or high-dose tamoxifen alone had any effect on LH secretion, as concentrations during tamoxifen treatments were indistinguishable from those during placebo. In Experiment 2, females were randomly assigned to one of four treatment groups (placebo, n = 6; estradiol, n = 5; tamoxifen only, n = 5; or tamoxifen plus estradiol, n = 6) to assess the effects on glucocorticoid negative feedback and pituitary and adrenal responsiveness to exogenous corticotropin- releasing hormone (CRH). Tamoxifen also antagonized the facilitating effects of estradiol on basal and CRH-induced ACTH and cortisol secretion. However, this antagonism produced basal and CRH-stimulated cortisol and ACTH concentrations that were lower than placebo-treated females. Interestingly, tamoxifen in the absence of estradiol produced a similar diminution in ACTH and cortisol response. These data suggest that, in the presence of estradiol, tamoxifen not only antagonized estrogenic facilitation of HPA responsivity but also actually attenuated the response compared with the placebo-treatment condition. Taken together, these data indicate that tamoxifen acts as an estrogen antagonist on the neural circuits controlling the neuroendocrine regulation of the hypothalamic-pituitary-ovarian and adrenal axes in ovariectomized macaque females.

Reduction of CTLL-2 cytotoxicity by induction of apoptosis with a Fas-estrogen receptor chimera

Allogeneic bone marrow transplantation and donor lymphocyte infusion are powerful treatments for chemotherapy-resistant leukemia. Tumor eradication is attributed to a graft-versus-leukemia reaction by the donor-derived cytotoxic T lymphocytes (CTLs), but the same cell population may cause severe graft-versus-host disease. One strategy to suppress harmful CTL activity is to incorporate a suicide gene into the donor lymphocytes prior to infusion, and to destroy these cells when they aggressively attack nonmalignant host tissues. In this study, we investigated the feasibility of using a Fas-estrogen receptor fusion protein (MfasER) to control T cell-mediated cytotoxicity, based on our previous finding that the chimera transmits a Fas-mediated death signal through activation by estrogen binding. A murine CTL line CTLL-2 was transfected with a vector encoding MfasER, and the growth, viability and cytotoxic activity of the transfected cells (CTLL/MfasER) were analyzed. The expression of apoptosis-related proteins such as Fas ligand and perforin was also investigated. In the absence of estrogen, CTLL/MfasER showed similar growth to parental CTLL-2, and the killing activity was preserved. Addition of 10 (-7) M estrogen induced a rapid apoptosis of CTLL/MfasER, and the cytotoxicity was severely impaired. A decrease of Fas ligand and perforin in the estrogen-treated CTLL/MfasER was seen in an immunoblot analysis. These functional and biochemical analyses showed that the estrogen-inducible apoptosis in MfasER-expressing CTLs rapidly terminated their target cell killing. The feasibility of using the MfasER-estrogen system to control graft-versus-host disease was demonstrated.

Beneficial effects of pravastatin in peri- and postmenopausal hyperlipidemic women: a 5-year study on serum lipid and sex hormone levels

OBJECTIVES

The aims of the present study are to assess the 5 year effects of pravastatin on serum lipids and lipoproteins in women around the menopause and to assess the effects of pravastatin on serum gonadotropins and sex steroid levels over a long-term period.

METHODS

We evaluated the long-term efficacy of pravastatin on serum lipid levels (total cholesterol, LDL-cholesterol, HDL-cholesterol, triglyceride) in 121 patients (47 premenopausal and 74 postmenopausal women) suffering from primary hypercholesterolemia. The effects of this lipid-lowering drug on serum gonadotropins and sex steroids (estradiol, estrone, and testosterone) are also reported.

RESULTS

Pravastatin produced a remarkable reduction in the serum total cholesterol level of 19.2+/-9.3% (P<0.0001) and 18.9+/-11.8% (P<0.0001), and in LDLl-cholesterol of 25.1+/-18.7% (P<0.0001) and 24+/-18.0% (P<0.0001) after 24 and 60 months' treatment, respectively. In hypertriglyceridemia, pravastatin also produced a remarkable reduction in triglyceride of 29.3+/-27.3% (P<0.0001) and 39.9+/-20.4% (P<0.0001) after 24 and 60 months of treatment, respectively. We found that serum gonadotropins and sex steroid levels changed naturally as a function of age from pre-therapy levels in the premenopausal patients after 60 months of treatment.

CONCLUSIONS

Pravastatin was well tolerated over 5 years and was a very effective lipid-lowering agent for both hypercholesterolemia and hypertriglyceridemia with no effect on the biosynthesis of sex steroids. These findings suggest that pravastatin can be used in the treatment of hypercholesterolemia with/without high triglyceride levels in women around the menopause.

A selective amplifier gene for tamoxifen-inducible expansion of hematopoietic cells

BACKGROUND

We have developed a novel system for expansion of gene-modified hematopoietic stem/progenitor cells to overcome the low efficiency of current gene transfer methodology. This system involves 'selective amplifier genes', that encode fusion proteins between the granulocyte colony-stimulating factor receptor (GCR) and the hormone-binding domain of estrogen receptor (ER). Hematopoietic progenitors expressing the chimeras showed estrogen-responsive growth in a controllable manner. However, endogenous estrogen may activate the fusion proteins in vivo, depending on the hormonal status of the subjects.

METHODS

We replaced ER with a mutant receptor (TmR) which specifically binds to 4-hydroxytamoxifen (Tm), to overcome limitations with wild-type ER. Interleukin-3 (IL-3)-dependent Ba/F3 cells and hematopoietic progenitor cells transduced with the resultant fusion proteins (GCRTmR and delta GCRTmR) were examined for ligand-inducible growth.

RESULTS

GCRTmR- and delta GCRTmR-expressing Ba/F3 showed IL-3-independent growth in response to Tm, while the cells were unresponsive to estrogen at concentrations up to 10(-7)-10(-6) M. Furthermore, murine bone marrow cells transduced with GCRTmR and delta GCRTmR formed colonies in methyl-cellulose medium in response to Tm, while virtually no colonies appeared with 10(-7) M estrogen or without cytokines.

CONCLUSIONS

These results suggest that influences of the endogenous estrogen can be almost eliminated by using the GCRTmR/Tm or delta GCRTmR/Tm system to expand gene-modified hematopoietic stem/progenitor cells.

Expression of P450c17 messenger ribonucleic acid in postmenopausal human ovary tissues

OBJECTIVE

To investigate the expression of the P450c17 gene in postmenopausal human ovaries compared with normal cycling ovaries.

DESIGN

Prospective nonrandomized clinical research study.

SETTING

Servei de Medicina Reproductiva and Centre d'Investigacions en Bioquimica i Biologia Molecular, Hospitals Vall d'Hebron, Barcelona, Spain.

PATIENT(S)

Six premenopausal women and four postmenopausal women undergoing bilateral oophorectomy for nonovarian gynecologic disease.

INTERVENTION(S)

Extraction of 10 mL of peripheral venous blood for hormone measurements. Extraction of RNA from surgically removed ovaries for Northern blot, ribonuclease protection, and reverse transcriptase polymerase chain reaction Southern blot assays.

MAIN OUTCOME MEASURE(S)

Definition of the reproductive cycle state of each patient and determination of the level of P450c17 gene expression in all samples with the use of the semiquantitative reverse transcriptase polymerase chain reaction Southern blot assay.

RESULT(S)

P450c17 messenger RNA levels in postmenopausal ovaries varied considerably between samples. Although the levels were similar to those detected in the early follicular phase, one of the samples had levels as high as those observed in the late follicular phase.

CONCLUSION(S)

Although the degree varied from one sample to another, all the postmenopausal ovaries studied expressed the P450c17 gene at the messenger RNA level. In a sample from a patient with endometrial adenocarcinoma, the level was as high as the levels observed in the late follicular phase.

Evidence for attenuation of gonadotropin pulse frequency in hypergonadotropic women with estradiol secretion in the menopausal transition

To investigate neuroendocrine interventions for climacteric symptoms in peri- and post-menopausal periods, the association between endocrine status and symptoms was examined in 519 peri- and post-menopausal women with climacteric symptoms. Furthermore, we evaluated the nature of putative disturbances in pulsatile gonadotropin (FSH and LH) secretion in 14 hypergonadotropic women with estradiol secretion and 16 hypergonadotropic women with hypoestrinism. We observed that 68.6% (356/519) of women with climacteric symptoms and 49.2% (121/246) of women in good health showed hypergonadotropinemia, and that 39.3% (140/356) of hypergonadotropic women with climacteric symptoms and 23.1% (28/121) of healthy women (controls) showed estradiol secretion (p < .002). In particular, the endocrinological profile of hypergonadotropinemia with estradiol secretion was observed in 67.1% (60/92) of pre-menopausal women with climacteric symptoms, approximately 2 x higher than that in healthy women (p < .005). Mental symptoms were observed at a significantly higher incidence in women with the endocrinological profile of hypergonadotropinemia with estradiol secretion compared with that in women with hypergonadotropic hypoestrinism showing a symptomatic profile, namely 25.0 versus 6.9% for mood lability (p < .001), and 21.4 versus 9.3% for anxiety symptoms (p < .001). Moreover, in vivo FSH and LH pulse frequencies were observed in only 14.3 and 18.6% of women with hypergonadotropinemia with estradiol secretion whereas such pulses were observed in all women with hypergonadotropic hypoestrinism. We also observed FSH and LH pulse frequencies in hypergonadotropinemia with estradiol secretion 0.14 +/- 0.35 and 0.29 +/- 0.45/3 h, respectively compared with those in hypergonadotropinemia without estradiol secretion 2.25 +/- 0.91 and 2.81 +/- 0.73/3 h, respectively (p < .001). Such findings are considered to be consistent with diminished hypothalamic GnRH impulse strength. In summary, we infer that decreased pulse frequencies in FSH and LH secretion are due to decreased hypothalamic GnRH impulse strength in women with the endocrinological profile of hypergonadotropinemia with estradiol secretion. As the potential mechanisms of this finding, it should be considered that specific endocrine environments damage the pulse generator mechanism in the diencephalon, and that changes occur in the pituitary responsiveness to GnRH (changes in receptor function).

Prophylactic oophorectomy: a continuing controversy

Prophylactic oophorectomy remains a controversial issue among gynecological surgeons. A woman's history of hereditary ovarian cancer syndrome is currently considered the most important indication for prophylactic oophorectomy. This is because of the high risk of ovarian cancer developing in these women and the poor prognosis that is generally associated with ovarian cancer. The purpose of prophylactic oophorectomy in women with no family history of hereditary ovarian cancer syndrome who present for hysterectomy because of other gynecological indications is, however, less clear. The attitude of the patients toward removal of normal ovaries deserves special consideration when counseling for prophylactic oophorectomy in this group of women. Knowledge about the risk of ovarian cancer in the conserved ovaries, cancer phobia, possible psychological effects of prophylactic oophorectomy, and the need for long-term hormone replacement therapy if prophylactic oophorectomy is carried out, are all important considerations in the counseling process.

Fas and mutant estrogen receptor chimeric gene: a novel suicide vector for tamoxifen-inducible apoptosis

Several cancer gene therapy strategies involve suicide genes to kill the neoplasm, or to regulate effector cells such as lymphocytes. We have developed an inducible apoptosis system with a Fas-estrogen receptor fusion protein (MfasER) for rapid elimination of transduced cells. In the present study, we further improved this molecular switch for estrogen-inducible apoptosis to overcome concerns with the wild-type estrogen receptor and its natural ligand, 17beta-estradiol (E2). The ligand-binding domain of MfasER was replaced with that of a mutant estrogen receptor which is unable to bind estrogen yet retains affinity for a synthetic ligand, 4-hydroxytamoxifen (Tm). The resultant fusion protein (MfasTmR) and MfasER were expressed in L929 cells for examination of their ligand specificities. Tm induced apoptosis in MfasTmR-expressing cells (L929MfasTmR) at 10(-8) M or higher concentrations, but induced no apoptosis in MfasER-expressing cells (L929MfasER) at up to 10(-6) M. On the other hand, E2 induced apoptosis in L929MfasER at concentrations as low as 10(-10)-10(-9) M, while it did so partially in L929MfasTmR at concentrations greater than 10(-7) M. Thus, L929MfasTmR cells were highly susceptible to Tm, but refractory to E2, with 100-1,000 times more tolerance than L929MfasER. These results suggest that the MfasTmR/Tm system would induce apoptosis in the target cells more safely in vivo, working independently of endogenous estrogen.

Ovarian testosterone secretion during perimenopause

OBJECTIVE

The aim of the study was to investigate ovarian testosterone secretion during the last few years of reproductive life and after menopause.

MATERIALS AND METHODS

Ovarian and peripheral venous levels of total testosterone were analyzed in 52 women aged 42-69 years (mean 51) undergoing hysterectomy with adnexal removal for benign indications at the Department of Obstetrics and Gynecology at Tampere University Hospital, Finland. The study population was divided into pre- (n = 19), peri- (n = 18) and postmenopausal (n = 15) women in addition to the classical division according to menstrual cycle. Corresponding serum estradiol, progesterone and gonadotropin levels were measured, and the degree of ovarian stromal hyperplasia was analyzed.

RESULTS

The levels of all steroid hormones were higher in the ovarian vein than in the periphery. A significant positive correlation was found between age and ovarian vein testosterone levels (r = 0.3, P = 0.01). In premenopausal women, it was 1.5 nmol/l (median; range 0.78-6.0), in perimenopausal women 2.2 nmol/l (range 0.9-13.6), and 2.5 nmol/l (range 0.6-26.6) in postmenopause, respectively. Peripheral testosterone level did not increase with age. Ovarian stromal hyperplasia was significantly associated with increased testosterone secretion (P = 0.009).

CONCLUSION

The ovary seems to increase the secretion of testosterone into circulation during the menopausal transition period, as the highest levels were measured in postmenopausal women. High testosterone levels in the ovarian vein, however, were not reflected in the peripheral venous blood.