Effect of oestradiol on turnover of type A monoamine oxidase in brain

Effects of gender-affirming hormone therapy on gray matter density, microstructure and monoamine oxidase A levels in transgender subjects

MAO-A catalyzes the oxidative degradation of monoamines and is thus implicated in sex-specific neuroplastic processes that influence gray matter (GM) density (GMD) and microstructure (GMM). Given the exact monitoring of plasma hormone levels and sex steroid intake, transgender individuals undergoing gender-affirming hormone therapy (GHT) represent a valuable cohort to potentially investigate sex steroid-induced changes of GM and concomitant MAO-A density. Here, we investigated the effects of GHT over a median time period of 4.5 months on GMD and GMM as well as MAO-A distribution volume. To this end, 20 cisgender women, 11 cisgender men, 20 transgender women and 10 transgender men underwent two MRI scans in a longitudinal design. PET scans using [11C]harmine were performed before each MRI session in a subset of 35 individuals. GM changes determined by diffusion weighted imaging (DWI) metrics for GMM and voxel based morphometry (VBM) for GMD were estimated using repeated measures ANOVA. Regions showing significant changes of both GMM and GMD were used for the subsequent analysis of MAO-A density. These involved the fusiform gyrus, rolandic operculum, inferior occipital cortex, middle and anterior cingulum, bilateral insula, cerebellum and the lingual gyrus (post-hoc tests: pFWE+Bonferroni < 0.025). In terms of MAO-A distribution volume, no significant effects were found. Additionally, the sexual desire inventory (SDI) was applied to assess GHT-induced changes in sexual desire, showing an increase of SDI scores among transgender men. Changes in the GMD of the bilateral insula showed a moderate correlation to SDI scores (rho = - 0.62, pBonferroni = 0.047). The present results are indicative of a reliable influence of gender-affirming hormone therapy on 1) GMD and GMM following an interregional pattern and 2) sexual desire specifically among transgender men.

In search of sex-related mediators of affective illness

Sex differences in the rates of affective disorders have been recognized for decades. Studies of physiologic sex-related differences in animals and humans, however, have generally yielded little in terms of explaining these differences. Furthermore, the significance of these findings is difficult to interpret given the dynamic, integrative, and highly context-dependent nature of human physiology. In this article, we provide an overview of the current literature on sex differences as they relate to mood disorders, organizing existing findings into five levels at which sex differences conceivably influence physiology relevant to affective states. These levels include the following: brain structure, network connectivity, signal transduction, transcription/translation, and epigenesis. We then evaluate the importance and limitations of this body of work, as well as offer perspectives on the future of research into sex differences. In creating this overview, we attempt to bring perspective to a body of research that is complex, poorly synthesized, and far from complete, as well as provide a theoretical framework for thinking about the role that sex differences ultimately play in affective regulation. Despite the overall gaps regarding both the underlying pathogenesis of affective illness and the role of sex-related factors in the development of affective disorders, it is evident that sex should be considered as an important contributor to alterations in neural function giving rise to susceptibility to and expression of depression.

Subchronic glucocorticoids, glutathione depletion and a postpartum model elevate monoamine oxidase a activity in the prefrontal cortex of rats

Recent human brain imaging studies implicate dysregulation of monoamine oxidase-A (MAO-A), in particular in the prefrontal cortex (PFC) and anterior cingulate cortex (ACC), in the development of major depressive disorder (MDD). This study investigates the influence of four alterations underlying important pathologies of MDD, namely, chronic elevation of glucocorticoid levels, glutathione depletion, changes in female gonadal sex hormones and serotonin concentration fluctuation, on MAO-A and MAO-B activities in rats. Young adult rats exposed chronically to the synthetic glucocorticoid dexamethasone at 0, 0.05, 0.5, and 2.0mg/kg/day (osmotic minipumps) for eight days showed significant dose-dependent increases in activities of MAO-A in PFC (+17%, p<0.001) and ACC (+9%, p<0.01) and MAO-B in PFC (+14%, p<0.001) and increased serotonin turnover in the PFC (+31%, p<0.01), not accounted for by dexamethasone-induced changes in serotonin levels, since neither serotonin depletion nor supplementation affected MAO-A activity. Sub-acute depletion of the major antioxidant glutathione by diethyl maleate (5mmol/kg, i.p.) for three days, which resulted in a 36% loss of glutathione in PFC (p=0.0005), modestly, but significantly, elevated activities of MAO-A in PFC and MAO-B in PFC, ACC and hippocampus (+6-9%, p<0.05). Changes in estrogen and progesterone representing pseudopregnancy were associated with significantly elevated MAO-A activity in the ACC day 4-7 postpartum (10-18%, p<0.05 to p<0.0001) but not the PFC or hippocampus. Hence, our study provides data in support of strategies targeting glucocorticoid and glutathione systems, as well as changes in female sex hormones for normalization of MAO-A activities and thus treatment of mood disorders.

Selective dietary supplementation in early postpartum is associated with high resilience against depressed mood

Medical research is moving toward prevention strategies during prodromal states. Postpartum blues (PPB) is often a prodromal state for postpartum depression (PPD), with severe PPB strongly associated with an elevated risk for PPD. The most common complication of childbearing, PPD has a prevalence of 13%, but there are no widespread prevention strategies, and no nutraceutical interventions have been developed. To counter the effects of the 40% increase in monoamine oxidase A (MAO-A) levels that occurs during PPB, a dietary supplement kit consisting of monoamine precursor amino acids and dietary antioxidants was created. Key ingredients (tryptophan and tyrosine) were shown not to affect their total concentration in breast milk. The aim of this open-label study was to assess whether this dietary supplement reduces vulnerability to depressed mood at postpartum day 5, the typical peak of PPB. Forty-one healthy women completed all study procedures. One group (n = 21) received the dietary supplement, composed of 2 g of tryptophan, 10 g of tyrosine, and blueberry juice with blueberry extract. The control group (n = 20) did not receive any supplement. PPB severity was quantitated by the elevation in depressed mood on a visual analog scale following the sad mood induction procedure (MIP). Following the MIP, there was a robust induction of depressed mood in the control group, but no effect in the supplement group [43.85 ± 18.98 mm vs. 0.05 ± 9.57 mm shift; effect size: 2.9; F(1,39) = 88.33, P < 0.001]. This dietary supplement designed to counter functions of elevated MAO-A activity eliminates vulnerability to depressed mood during the peak of PPB.

Tamoxifen antagonizes the effects of ovarian hormones to induce anxiety and depression-like behavior in rats

The effects of tamoxifen (TAM) on anxiety and depression-like behavior in ovariectomized (OVX) and naïve female rats were investigated. The animals were divided into Sham-TAM, OVX-TAM, Sham and OVX groups. Tamoxifen (1 mg/kg) was administered for 4 weeks. In the forced swimming test, the immobility times in the OVX and Sham-TAM groups were higher than in the Sham group. In the open field, the numbers of central crossings in the OVX and Sham-TAM groups were lower than the number in the Sham group, and the number of peripheral crossings in the OVX group was lower than the number in the Sham group. In the elevated plus maze, the numbers of entries to the open arm among the animals in the Sham-TAM and OVX groups were lower than the number in the Sham group, while the number of entries to the open arm in the OVX-TAM group was higher than the number in the OVX group. It was shown that deletion of ovarian hormones induced anxiety and depression-like behavior. Administration of tamoxifen in naïve rats led to anxiety and depression-like behavior that was comparable with the effects of ovarian hormone deletion. It can be suggested that tamoxifen antagonizes the effects of ovarian hormones. It also seems that tamoxifen has anxiolytic effects on ovariectomized rats.

Sex hormones affect neurotransmitters and shape the adult female brain during hormonal transition periods

Sex hormones have been implicated in neurite outgrowth, synaptogenesis, dendritic branching, myelination and other important mechanisms of neural plasticity. Here we review the evidence from animal experiments and human studies reporting interactions between sex hormones and the dominant neurotransmitters, such as serotonin, dopamine, GABA and glutamate. We provide an overview of accumulating data during physiological and pathological conditions and discuss currently conceptualized theories on how sex hormones potentially trigger neuroplasticity changes through these four neurochemical systems. Many brain regions have been demonstrated to express high densities for estrogen- and progesterone receptors, such as the amygdala, the hypothalamus, and the hippocampus. As the hippocampus is of particular relevance in the context of mediating structural plasticity in the adult brain, we put particular emphasis on what evidence could be gathered thus far that links differences in behavior, neurochemical patterns and hippocampal structure to a changing hormonal environment. Finally, we discuss how physiologically occurring hormonal transition periods in humans can be used to model how changes in sex hormones influence functional connectivity, neurotransmission and brain structure in vivo.

Greater monoamine oxidase a binding in perimenopausal age as measured with carbon 11-labeled harmine positron emission tomography

IMPORTANCE

Perimenopause is a period of high risk for mood disorders, and it has been proposed that perimenopause is also a window of risk for processes linked to later dementia. However, in human perimenopause, the neurobiological changes implicated in the genesis of mood disorders or dementia have not been identified. Monoamine oxidase A (MAO-A) is an important brain enzyme that creates oxidative stress, influences apoptosis, and metabolizes monoamines. After declines in estrogen level, MAO-A density may be elevated for a month or longer, and repeated declines in estrogen level occur with greater magnitude during perimenopause.

OBJECTIVE

To investigate whether MAO-A total distribution volume (VT), an index of MAO-A density, is elevated in women of perimenopausal age (41-51 years).

DESIGN, SETTING, AND PARTICIPANTS

In a cross-sectional study at a tertiary care psychiatric hospital, 58 women underwent carbon 11-labeled harmine positron emission tomography. These included 19 young women of reproductive age (mean [SD], 28.26 [5.05] years), 27 women of perimenopausal age (mean [SD] age, 45.21 [3.41] years; including 14 women with change in menstrual cycle length with a mean [SD] age of 45.50 [4.00] years and 13 women with no change in menstrual cycle length with a mean [SD] age of 44.92 [2.81] years), and 12 women in menopause (mean [SD] age, 56.25 [3.19] years).

MAIN OUTCOMES AND MEASURES

Values of MAO-A VT in the prefrontal cortex, anterior cingulate cortex, dorsal striatum, ventral striatum, thalamus, hippocampus, and midbrain.

RESULTS

On average, MAO-A VT in perimenopausal age was elevated by 34% compared with reproductive age and by 16% compared with menopause (multivariate analysis of variance, group effect, F16,94 = 3.03; P < .001). Within the perimenopausal age group, meeting Stages of Reproductive Aging Workshop criteria for perimenopause, which is mainly based on menstrual cycle length, was not associated with MAO-A VT (F8,18 = 0.548; P = .81) but tendency to cry was positively correlated with MAO-A VT in the prefrontal cortex (r = 0.54; P = .008).

CONCLUSIONS AND RELEVANCE

To our knowledge, this is the first report of a change in a central biomarker during perimenopausal age that is also present during major depressive episodes and high-risk states for major depressive episodes. The functions of MAO-A influence oxidative stress and apoptosis, 2 processes implicated as excessive in both mood disorders and dementia. Hence, greater MAO-A VT during perimenopause may represent a new target for assessing novel interventions to prevent mood disorders and reduce longer-term risk of neurodegenerative disease.

Hormone-replacement therapy, dementia and stroke

Hormone-replacement therapy (HRT) has been used for more than 40 years to reduce perimenopausal symptoms. Estrogens may protect brain structures and functional systems affected by Alzheimer's disease, which suggests that maintaining high levels of hormones with HRT can protect against Alzheimer's disease. Moreover, high premenopausal estrogen concentrations are thought to be protective against stroke and, consequently, in the past, HRT was considered to be a potential protective agent against stroke. However, large clinical trials have failed to demonstrate a benefit from HRT on either cognitive performance or risk of dementia. In addition, although HRT has been associated with a reduction in the risk of heart disease in observational studies, results regarding stroke have been less clear. Recently, evidence has shown that HRT does not reduce but actually increases vascular risk. Here, the data from the most important studies are examined, concluding that HRT has no beneficial effect on dementia or stroke risk reduction in postmenopausal women.

Antidepressive and anxiolytic activity of selective estrogen receptor modulators in ovariectomized mice submitted to chronic unpredictable stress

Estradiol has antidepressive and anxiolytic actions. However, its therapeutic use is limited by its peripheral effects. Selective estrogen receptor modulators may represent an alternative to estradiol for the treatment of depressive symptoms. Here we report that tamoxifen and raloxifene decrease immobility time in the forced swim test and increases the time spent in open arms in the elevated plus maze in ovariectomized mice submitted to chronic unpredictable stress.

II. Cognitive performance of middle-aged female rats is influenced by capacity to metabolize progesterone in the prefrontal cortex and hippocampus

Cognitive decline can occur with aging; however, some individuals experience less cognitive decline than do others. Secretion of ovarian hormones is reduced post-menopause and may contribute to cognitive function. The extent to which hormonal effects may be parsed out from other age-related factors to influence cognition is of interest. Middle-aged (12-month-old) female rats that were retired breeders were categorized as maintaining or declining reproductive function based upon their estrous cyclicity (regular 4-5 day cycles), fertility (> 60 % successful pregnancy), and fecundity (>10 pups/litter). Performance in object recognition, Y-maze, water maze, inhibitory avoidance, and contextual-cued fear conditioning was evaluated. Estradiol, progesterone (P(4)), dihydroprogesterone, and 5α-pregnan-3α-ol-20-one (3α,5α-THP) were assessed in medial prefrontal cortex (mPFC) and hippocampus; corticosterone was assessed in plasma. Rats maintaining reproductive function performed significantly better on the object recognition, Y-maze, water maze, inhibitory avoidance, and cued fear conditioning tasks than did rats with declining reproductive function. Steroid concentrations varied greatly within groups. Higher levels of P(4) in mPFC and hippocampus were associated with better Y-maze performance. In mPFC, higher levels of P(4) were associated with poorer inhibitory avoidance performance; greater levels of 3α,5α-THP were associated with better object memory. Neither estradiol nor corticosterone levels significantly contributed to cognitive performance. Thus, the capacity for cortico-limbic P(4) utilization may influence cognitive performance in aging.

Decreased blood serotonin in the premenstrual phase enhances negative mood in healthy women

The purpose of this study was to evaluate mechanisms underlying the action of selective serotonin reuptake inhibitors on the improvement of negative mood symptoms in premenstrual syndrome. We assessed relationships between serotonin (5-HT) levels in the brain (estimated from 5-HT concentrations in whole blood) and negative mood states during the premenstrual phase in 13 healthy women. Mood states were evaluated using the Profile of Mood States questionnaire. We also evaluated relationships between 5-HT and ovarian hormones (oestradiol and progesterone). A significant negative correlation was seen between 5-HT concentrations in whole blood and negative mood scores (tension-anxiety and fatigue) observed in the premenstrual phase. A significant positive correlation was observed between 5-HT and oestradiol in the premenstrual phase, but not in the follicular phase. These results suggest that healthy women with lower whole blood 5-HT concentrations in the premenstrual phase exhibit enhanced negative mood due to lower 5-HT concentrations at brain synapses, which may be caused in part by lower oestrogen concentration.

Progesterone and progestins: effects on brain, allopregnanolone and beta-endorphin

The increased use of hormonal therapies over the last years has led to improve the knowledge of pharmacological, biochemical and metabolic properties of several progestins and their effects in target tissues, such as the central nervous system. Progesterone and synthetic progestational agents are able to modulate the synthesis and release of several neurotransmitters and neuropeptides in response to specific physiological and pathological stimuli. While these actions may relay on differential activation of progesterone receptor or recruitment of intracellular pathways, some of the differences found between synthetic progestins may depend on the specific conversion to neuroactive steroids, such as the 3-alpha, 5-alpha reduced metabolite, allopregnanolone. This is a potent endogenous steroid that rapidly affects the excitability of neurons and glia cells through direct modulation of the GABA-A receptors activity exerting hypnotic/sedative, anxiolytic, anaesthetic and anticonvulsive properties. Estrogens increase the CNS and serum levels of allopregnanolone and the addition of certain but not all synthetic progestins determines a further increase in allopregnanolone levels, suggesting that the metabolism into this reduced product is related to the chemical structure of progestin molecule used. In addition, depending on specific progestin molecule used, different interaction are found with the estradiol-induced beta-endorphin synthesis and release, showing that diverse progestins have specific and divergent actions on the opiatergic system. These results highlight the concept that natural and synthetic progesterone receptor agonists may systematically induce different biological actions in CNS. This may have far-reaching implications for the clinical effects and related indications of each compound.

Hormones and dementia - a comparative study of hormonal impairment in post-menopausal women, with and without dementia

CONTEXT

Women seem to be more vulnerable to dementia, particularly Alzheimer's disease (AD), than men. There is controversy among studies correlating estrogen deficit to cognitive impairment. Because of the sudden drop of estrogens in menopause, this hormonal deficit could represent one of the risk factors for the larger incidence and prevalence of AD in post-menopausal women.

RATIONALE

We therefore wanted to find out if post-menopausal women with dementia, or even in a prior stage, mild cognitive impairment (MCI), would have a more significant deficit of estrogens than post-menopausal women without dementia, or any other type of cognitive problem.

OBJECTIVES

The aim of this study was to detect possible differences of the sex hormone levels among post-menopausal women, simultaneously affected by MCI or dementia, in comparison with a control group without cognitive impairment.

DESIGN, SETTING, AND PARTICIPANTS

A small, multicenter, prospective study was performed on 82 post-menopausal women (41 cases, 41 controls), aged 45-81 years, to investigate their sex hormone balance. The diagnosis of dementia was made according to ICD 9 or 10 and DSM III-R or IV appropriate to the time interval. The diagnosis of probable AD followed the NINCDS-ADRDA criteria. MCI met the Paquid-study criteria. Blood was analyzed in qualified centers for LH, FSH, and 17-beta-estradiol. All women went through a thorough psychiatric examination and those with a suspected hormonal impairment were examined by a gynecologist.

RESULTS

15 cases (36.6%) had impaired hormonal function, compared with 8 controls (19.5%). Of the 15 cases with hormonal impairment, 9 had MCI.

CONCLUSIONS

These preliminary data stress a considerable difference between the sex hormone status of these two populations, showing a tendency towards a more accentuated estrogen deficit linked to cognitive deficit. Enlarging the sample and following the evolution could bring more interesting data.

Endocrinology of menopausal transition and its brain implications

The central nervous system is one of the main target tissues for sex steroid hormones, which act on both through genomic mechanisms, modulating synthesis, release, and metabolism of many neuropeptides and neurotransmitters, and through non-genomic mechanisms, influencing electrical excitability, synaptic function, morphological features, and neuron-glia interactions. During the climacteric period, sex steroid deficiency causes many neuroendocrine changes. At the hypothalamic level, estrogen withdrawal gives rise to vasomotor symptoms, to eating behavior disorders, and altered blood pressure control. On the other hand, at the limbic level, the changes in serotoninergic, noradrenergic, and opioidergic tones contribute to the modifications in mood, behavior, and nociception. Hormone replacement therapy (HRT) positively affects climateric depression throughout a direct effect on neural activity and on the modulation of adrenergic and serotoninergic tones and may modulate the decrease in cognitive efficiency observed in climaterium. The identification of the brain as a de novo source of neurosteroids, suggests that the modifications in mood and cognitive performances occurring in postmenopausal women may also be related to a change in the levels of neurosteroids. These findings open new perspectives in the study of the effects of sex steroids on the central nervous system and on the possible use of alternative and/or auxiliary HRT.

Efficacy of the herbal medicine Unkei-to as an adjunctive treatment to hormone replacement therapy for postmenopausal women with depressive symptoms

OBJECTIVE

Although hormone replacement therapy (HRT) improves menopausal depressive symptoms, women unresponsive to HRT need an antidepressant drug as an effective adjunctive therapy. The aim of this study was to assess whether the herbal medicine Unkei-to has an impact on HRT-resistant menopausal depressive symptoms as an effective adjunctive therapy combined with HRT.

METHODS

Twenty-four HRT-resistant menopausal depressive women were randomly assigned to group 1 (n = 12) or group 2 (n = 12). Subjects in group 1 were accessioned into 6 months of open treatment with Unkei-to as an adjunctive therapy and changed to Toki-shakuyaku-san for 6 months following a 1-month washout period. Group 2 started with Toki-shakuyaku-san for 6 months and then changed to Unkei-to for 6 months following a 1-month washout period.

RESULTS

Three months' treatment with Unkei-to as an adjunctive therapy significantly improved Zung's Self-Rating Depression Scale (ZSDS) scores, State-Anxiety (STAI-1) scores, and Trait-Anxiety (STAI-2) scores noted before treatment, and this effect continued at 6 months. Treatment with Unkei-to was also significantly effective in reduction of ZSDS scores, STAI-1 scores, and STAI-2 scores at 3 months compared with Toki-shakuyaku-san treatment, and this effect continued at 6 months.

CONCLUSIONS

Unkei-to is another option as an adjunctive herbal therapy in HRT-resistant menopausal depressive women.

The effect of the menstrual cycle on electrophysiological and behavioral measures of memory and mood

Event-related potentials (ERPs) were compared between the menses and ovulatory phase of the menstrual cycle in response to visually presented words, some of which were repeated as part of direct and indirect memory tasks. Twelve spontaneously cycling women were tested during the menses and ovulatory phases. For the direct task, participants had to discriminate between new words and those repeated after a mean of six trials. In the indirect task, subjects were required to discriminate between target and nontarget words. Some of the nontarget words were repeated after a mean of six trials. The ERP repetition effect mean amplitude was significantly greater in response to repeated words at both cycle phases but did not differ across the cycle. P300 amplitude was significantly greater during menses than the ovulatory phase. We conclude that context updating mechanisms as indexed by the P300 are sensitive to cyclic hormonal fluctuations.

CNS: sex steroids and SERMs

The central nervous system (CNS) is one of the main target tissues for sex steroid hormones, which act both through genomic mechanisms, modulating synthesis, release, and metabolism of many neuropeptides and neurotransmitters, and through nongenomic mechanisms, influencing electrical excitability, synaptic function, and morphological features. The identification of the brain as a de novo source of neurosteroids modulating cerebral function, suggests that the modifications in mood and cognitive performances occurring in postmenopausal women could also be related to a modification in the levels of neurosteroids, particularly allopregnanolone and DHEA, GABA-A agonist, and antagonist, respectively. The selective estrogen receptor modulators (SERMs) are compounds that activate the estrogen receptors with different estrogenic and antiestrogenic tissue-specific effects. In addition to the effects of the classic steroid hormones on the CNS, the study of selective estrogen receptor modulators impact on the neuroendocrine system has recently provided encouraging results, indicating that raloxifene analog LY 117018 and the new generation SERM EM-652 have an estrogen-like action on beta-endorphin and on allopregnanolone in ovariectomized rats, while they exert an anti-estrogenic effect in fertile rats and in ovariectomized rats treated with estrogens. In addition, raloxifene administration in postmenopausal women plays an estrogen-like effect on circulating beta-EP and allopregnanolone levels, and it restores the response of beta-EP and allopregnanolone to neuroendocrine tests. In conclusion, the positive effects of HRT on mood and cognition in postmenopausal women occur via the modulation of neuroendocrine pathways and probably also of neurosteroidogenesis. The effects of raloxifene on mood and cognition encourage the efforts in the research of an ideal estrogen replacement therapy, showing all the positive effects of estrogens and fewer side effects.

Alternatives to estrogen

For many years, women have sought alternative therapies for menopausal symptoms and for general health overall. The highly publicized findings from the Women's Health Initiative have led to an increased pressure on the medical community to find safe and alternative medications for female health. This article reviews the challenges and problems with the use of alternative medicines, and the clinical trials that prove their efficacy, and discusses the safety issues that may occur with these types of products.

Hormonal influence on the central nervous system

Sex steroids play a very important role in female neurobiology. Postmenopausal gonadal hormone withdrawal seem to be of critical importance in mood disorders, reduced libido and cognitive disturbances, which accompany this phase of a woman's life. Clinical studies have demonstrated that central nervous system (CNS) effects of estrogens are not only limited to resolution of vasomotor instability, they are extended to psychological disturbances like depression, behavioral changes and cognitive dysfunction. Progestins, on the other hand, may have variable effects on the brain, occasionally inducing dysphoric mood and altered behavior. Although their use in hormone replacement therapy (HRT) is widely debated, androgens may help resolve changes in libido experienced by many women after the menopause. It is still, however, difficult to draw guidelines on the use of HRT and postmenopausal CNS disorders as studies present up to date have been carried out with different kinds of molecules and routes of administration. Further studies are required in order to explain the specific role of endogenous and exogenous sex steroids on the CNS.

Lack of effects of acute estradiol on mood in postmenopausal women

Chronic treatment with estrogen is believed to improve mood in postmenopausal women, and recent preclinical evidence suggests that estradiol may also affect mood and behavior through acute neuronal membrane-mediated effects on the central nervous system. This study was designed to characterize potential mood effects of single doses of transdermal estradiol in healthy postmenopausal women who were not taking hormone replacement therapy (HRT). Twelve women participated in a five-session, within-subjects, double-blind study, in which they received placebo, transdermal estradiol (0.2, 0.4, and 0.8 mg), or D-amphetamine (15 mg, oral) in a randomized order. Amphetamine was included as a positive control. Dependent measures included self-report measures of mood, physiological measures, and plasma hormone levels. Despite dose-dependent increases in plasma estradiol levels, and despite the fact that D-amphetamine produced its prototypic stimulant-like effects in these postmenopausal women, estradiol did not produce effects on mood. The finding that acute administration of exogenous estradiol did not alter mood suggests that more chronic exposure to estradiol is needed to produce mood-enhancing effects.

The nature of the effect of female gonadal hormone replacement therapy on cognitive function in post-menopausal women: a meta-analysis

We reviewed epidemiological and experimental studies of female gonadal hormone replacement therapy (HRT) on cognitive function in post-menopausal women and carried out meta-analyses. In healthy ageing women, HRT has small and inconsistent effects that include enhancement of verbal memory, abstract reasoning and information processing. Epidemiological studies show larger effects than experimental studies, which is not related to sample size. Important confounds may be that women who start using HRT are healthier than women who do not. Also, controlling for socio-economic status diminishes the effect of HRT. The effects of HRT may depend on the age and type of menopause and the therapeutic intervention used, with the most widely used drug, Premarin, having least effect. However, the effects are independent of mood and climacteric symptom alleviation. There is a paucity of experimental studies that include healthy elderly women. The evidence for an estrogen deficiency in women with dementia and cognitive dysfunction is inconsistent. Nevertheless, epidemiological studies suggest that HRT protects against the development of clinically diagnosed Alzheimer's disease. However, poor recall of HRT use by patients and altered physician behaviour may have confounded the effects. Surprisingly, both healthy and demented women with low education seem to benefit most from HRT. Three recent controlled experimental studies using Premarin showed no effects of HRT in preventing further cognitive decline in women who already have Alzheimer's disease. Duration of treatment seems to play an important role, with beneficial effects declining-and even reversing-with longer treatment in women with Alzheimer's disease.Future research should further investigate the cognitive effect of different HRT preparations, serum estrogen levels, and the interactions of HRT with age, menopausal status and existing protective (e.g. education) and risk factors (e.g. smoking and apolipoprotein E genotype) for cognitive decline and Alzheimer's disease.

Menopause and depression: a review of psychologic function and sex steroid neurobiology during the menopause(1)

The purpose of this review is threefold. The first objective is to assess from current literature the extent to which depressive symptoms may be associated with peri- and postmenopausal states. Although there have been many studies published addressing this topic, there remains much controversy as to whether there is a true positive correlation of increased depressive symptomatology with the peri- and postmenopausal periods. Second, sex steroid neurobiology will be reviewed. In recent years, improved technology has allowed for much more detail in investigations of the central mechanisms of action of the sex hormones. Ultimately, estrogen appears to play an excitatory role in the central nervous system, whereas progesterone has been shown to be inhibitory. The third objective is to determine whether sex steroids have been shown to clinically affect mood and psychologic function, and if so, how such information might relate to regimens for peri- and postmenopausal hormone replacement. Currently, only large, pharmacologic doses of estrogen have been shown to improve mood in clinically depressed patients. Estrogen has been shown to potentiate the effects of some antidepressants; therefore menopausal women with major depressive disorders may respond to lower doses of antidepressant medications when estrogen replacement is added to the treatment regimen.The psychological and physiological manifestations in depressive illnesses of the post-menopausal age period are of great complexity and not clearly understood. In view of the obscurity of the etiological factors it is important to isolate and study the effect of one such possible factor at a time.1Many symptoms and signs of various mood disturbances have been attributed to estrogen deficiency during the climacteric, yet it has been argued that there are no psychological symptoms specific to the menopause. The literature concerning psychological symptoms accompanying menopause is confusing.2Taken from studies published more than 50 years apart, these quotes describe the long-standing difficulty investigators have faced in evaluating psychologic function during the menopause. From the 1930s to the present, ongoing debate has surrounded issues of depression associated with the peri- and postmenopausal periods: whether there is an association at all and if so, what the cause might be and how might it be treated. Investigators continue to add new information to this debate, driven by the common understanding that issues relating to menopause and the postmenopausal period have become increasingly important. Not only are greater numbers of women approaching menopause, but these women are now expected to live greater than one third of their lives after menopause.3 The purpose of this review is first to assess from the literature the extent to which depressive symptoms may be associated with peri- and postmenopausal states. Second, in an attempt to explain or define causes of proposed changes in psychologic function during menopause, sex steroid neurobiology will be reviewed. The last objective is to determine from the literature whether sex steroids as used in hormone replacement therapy have been shown to clinically affect mood and psychological function and if so, how such information might relate to regimens for peri- and postmenopausal hormone replacement.

Depressive mood symptoms associated with ovarian suppression

OBJECTIVE

To determine if sertraline is helpful in the management of depressive symptoms associated with ovarian suppression during GnRH agonist therapy as compared with a placebo-controlled group.

DESIGN

Double-blind placebo-controlled prospective study design.

SETTING

An obstetrics/gynecological office specializing in infertility in an academic environment.

PATIENT(S)

Premenstrual women with laparoscopically diagnosed endometriosis who required GnRH agonist therapy for treatment and did not have significant depressive or premenstrual mood symptoms at baseline.

INTERVENTION(S)

Participants were randomly assigned to either the sertraline treatment group or to the placebo group for the 3-month duration of the GnRH agonist therapy.

MAIN OUTCOME MEASURE(S)

The 21-item Hamilton Rating Scale for Depression (HRSD), which is an instrument designed to assess depressive symptomatology.

RESULT(S)

A Hotellings T(2) test for repeated measure analysis indicated a statistically significant (P<.05) between-group difference across time for the HRSD (T(2) = 13.3; F[3, 28] = 4.1; P=.02) with the sertraline treatment group manifesting significantly fewer depressive symptoms than the control group.

CONCLUSION(S)

The results indicate that sertraline is an effective option in the management of depressive mood symptoms associated with ovarian suppression during GnRH agonist therapy.

Estrogen, progestogen and tamoxifen increase synaptic density of the hippocampus of ovariectomized rats

The effects of gonadal steroids or tamoxifen over the synaptic density of the CA1 region of the hippocampus was investigated in ovariectomized (OVX) rats. Chronic oral administration of conjugated equine estrogen, conjugated equine medroxyprogesterone, a combination of both or tamoxifen was performed in ovariectomized (OVX) rats over a period of 60 days. Synaptic density of the stratum radiatum of the CA1 region was evaluated by means of electron microscopy. Significant increases in the range of 34-49% were found for treated animals as compared to OVX controls not subject to hormonal replacement. Our results confirm previously reported effects of estradiol over synaptic density in this region and reports for the first time an effect of medroxyprogesterone (alone or in combination with estrogen) and tamoxifen. Our findings support the notion that hormonal replacement therapy and tamoxifen might have beneficial effects for cognitive function.

Improvement in functions of the central nervous system by estrogen replacement therapy might be related with an increased nitric oxide production

Estrogen promotes neurons growth, prevents neuronal cell atrophy and regulates synaptic plasticity. Administration of estrogen protects neurons against oxidative stress, excitotoxins, and beta-amyloid-induced toxicity in cell culture. It has been shown that estrogen treatment reduces the serum monoamino oxidase levels and might regulate learning and memory. Nitric oxide (NO) is a retrograde messenger and long-term potentiation can be block using NO-synthase inhibitors or can be prevent with NO-scavengers. NO synthase is widespread in the central nervous system and acts as neurotransmitter/neuromodulator. The actions of serotonin, bradykinin, endothelin, acetylcholine and noradrenaline might be linked to NO formation. Estrogen induces activity of constitutive NO synthase and estrogen replacement therapy in postmenopausal women increases significantly circulating nitrite plus nitrate levels. The effect of estrogen on NO synthesis is rapid and is maintained with repeated administration. We demonstrated the effects of estrogen replacement therapy in Andean postmenopausal women were associated with a significantly increase in plasma levels of nitrite plus nitrate. Our hypothesis is that beneficial effect of estrogen replacement therapy on involutive depression in postmenopausal women is mediated by increase in NO production by central nervous system.

Effects of norethisterone acetate addition to estradiol in long term HRT

OBJECTIVE

The aim of this study was to evaluate the efficacy and tolerability of hormone replacement therapy (HRT) among postmenopausal women living in the Lund area of Southern Sweden and to analyze treatment effects in different types or routes of HRT administration, as well as to compare with unopposed estrogen therapy.

METHOD

in an ongoing, large population-based, prospective cohort study, this interim analysis included 3900 women. Of them, 693 postmenopausal women were eligible in the present analyses as they continued to use one of the four commercial HRT products for at least 2-3 years, i.e. continuous oral estradiol (E(2)) 2 mg+norethisterone acetate (NETA) 1 mg (CON-O), sequential oral estradiol 2 mg + norethisterone acetate 1 mg (CYC-O), sequential transdermal estradiol 50 microg + norethisterone acetate 250 microg (CYC-TRANS) and estradiol monotherapy. These women completed one generic questionnaire and one specific 'hormonal' questionnaire, as well as a personal interview pertaining to socio-demographics, detailed status of HRT use, and therapeutic efficacy and untoward side-effects by HRT.

RESULTS

comparing the three combined E(2)+NETA groups with E(2) monotherapy, the beneficial effects on sexual desire and emotional well-being were significantly less in the combined groups than in E(2) monotherapy group. There was no significant difference regarding the negative side-effects between the groups. No significant difference was found between CON-O and CYC-O groups either in positive effects or in negative side-effects. A higher prevalence of positive effects was found in CYC-TRANS group than that in CYC-O group, especially in amelioration of sleep and urinary symptoms. Higher odd ratios of negative effects by HRT, such as irregular bleeds, weight gain, food craving and skin disorders were also found in CYC-TRANS group.

CONCLUSION

in long-term HRT administration, the addition of a progestogen in HRT could compromise the beneficial effects of estradiol, particularly, the effects on women's emotional well being and psychosexual functioning. Administration of NETA continuously and sequentially had similar therapeutic efficacy and tolerability. More marked positive effects, such as improving of sleep and urinary symptoms, as well as nuisance side-effects, i.e. irregular bleeds, weight gain, food craving and skin disorders were encountered by the women using sequential transdermal regimen

Estrogen for dementia-related aggression in elderly men

OBJECTIVE

To report the use of conjugated estrogens for aggression in two elderly men with dementia and to review the available literature relating to estrogen use for aggression in the elderly.

CASE SUMMARIES

Case 1. A 78-year-old white man had probable Alzheimer dementia and aggression (verbal and physical) that was nonresponsive to antipsychotic, antidepressant, and mood stabilizer therapy. However, conjugated estrogens 1.875 mg/d reduced his physical aggression, as evidenced by a 75% decline in aggressive episodes, per 24-hour nursing reports and progress notes. Case 2. A 78-year-old African-American man with vascular dementia, physical aggression, and sexual inappropriateness was unsuccessfully managed with several antipsychotic and benzodiazepine trials. He did, however, exhibit a decline in physical and sexual aggression by 80%, as well as a 55% reduction in sexual comments, after daily treatment with conjugated estrogens 0.625 mg. Estrogen was well tolerated by both patients.

DATA SOURCES

MEDLINE (January 1966-May 1998) and PsychLit (January 1974-May 1998) database searches were performed to identify case reports, letters, or clinical trials discussing estrogen use in aggressive elderly patients.

CONCLUSIONS

As with previous reports, these cases suggest that conjugated estrogens may be used to reduce physical and sexual aggression associated with dementia in elderly men. Additional study is needed to determine the exact role of this alternative pharmacologic intervention.

Menopause and the central nervous system: intervention options

The central nervous system is an important target for sex steroid hormones. During the climateric period the rapid decline of gonadal steroids causes neuroendocrine changes in different areas of the brain. The failure of gonadal hormone production brings specific symptoms due to the central nervous system derangement. At the hypotalamic level estrogen withdrawal gives rise to vasomotor symptoms, eating behavior disorders and altered blood pressure control. Psychological disturbances such as depression, anxiety, irritability and mood fluctuation are related to estrogen-induced changes in the lymbic system. The hypothesis of specific neuroanatomical and neurophysiological effects of estrogen on the brain may also explain the correlation between estrogen deficiency and cognitive disturbances such as Alzheimer's type dementia (AD). The increasing interest in the influence of sex steroids on brain function has focused attention on hormonal replacement therapy. Clinical and epidemiological studies have demonstrated that estrogen therapy exerts a positive effect on vasomotor instability and improves psychological disturbances. The positive effects of estrogen on mood are probably related to its stimulatory action on adrenergic and serotoninergic tone. Estrogen may influence the cognitive function through different biological actions. Estrogen administration increases total cerebral and cerebellar blood flow, cerebral glucose administration and improves cholinergic tone, a key neurotransmitter in learning and memory. The evidence suggests that hormone replacement therapy may reduce the relative risk of developing AD. Progestagens and androgen may also have a role in the control of mood disorders. At present, few data are available regarding the influence that selective estrogen receptor modulators, a new class of compounds, can exert on the brain.

1998 Curt P. Richter Award. The effect of hormone replacement therapy on cognitive function in elderly women

Although evidence seems to indicate favorable effects of hormone replacement therapy (HRT) on cognitive functions and mood in elderly healthy and demented women, some questions remain. For instance, the nature of the long term effect of HRT, e.g. in preventing cognitive decline is still unclear. In this respect, the addition of progestagens in combined HRT has been mentioned to oppose some of the beneficial effects of estrogens. The present paper aims to illuminate these questions and presents two studies. In the first study, the long term effects of combined HRT in healthy postmenopausal women was investigated using a parallel groups (HRT-users vs. controls) design. HRT subjects were always tested during the estrogen-progestagen phase. Results indicated that after 6 and 12 months, women in the HRT-treatment group had higher scores on several indicators of the subjective feeling of well being (sleep, physical and psychological complaints) than matched controls, although at baseline both groups were not severely impaired. Effects of HRT on memory functions were seen when HRT treated subjects were compared with their own baseline functioning, but not when compared with controls. Hence, the addition of progestagen did not oppose the effects of estrogens on subjective feelings of well being or on memory. Our second (case-control) study involved women of middle-age who were unaware of the purpose of the experiment. No positive effects of HRT use on subjective scales of well being or on memory were found. However, women with HRT were faster on basic sensorimotor speed tasks as compared with controls. It should be kept in mind that double blind testing in an experimental study is difficult due to withdrawal bleeding and the reduction of flushes. Expectancy effects may have confounded the results of the first study. However, our findings indicate that the use of a particular design and type of memory test can explain the controversial results of studies into the effect of HRT on cognitive function. Furthermore, it was concluded that HRT has a global activating, instead of specific direct effect on cognitive functions.

The psychotherapeutic effects of estrogens

The effect of estrogens on the central nervous system, particularly mood and behavior, remains a controversial area which needs clarification, not just for understanding of depression in women but to ensure that such commonplace problems in women have efficient and appropriate therapy. There is now good evidence that estrogens are rapidly effective in the treatment of depression in many women but this information has not found its way through to those health care personnel, psychiatrists and psychologists who are principally involved in the treatment of depression. There is also strong evidence for the benefits of estrogens on cognitive functioning, not only in preventing the onset of dementia but also in improving the symptoms in the established condition. Recent work has also suggested a benefit for estrogens on mood in women diagnosed as suffering from chronic fatigue syndrome. This article reviews the effect of endogenous estrogen on the female central nervous system and the ever increasing evidence for the diverse psychotherapeutic effects of exogenous estrogens.

Tissue-specific effects of estrogen on monoamine oxidase A and B in the rat

Estrogen replacement therapy is widely used in postmenopausal women. The current study examines the effect of varying concentrations of estrogen on the levels of activity of monoamine oxidase A and -B in brain and in other tissues. Adult female rats were ovariectomized and randomized to receive a subcutaneous, slow-release preparation of either placebo or one of three doses of 17-beta-estradiol (0.05, 0.5, or 5.0 mg/pellet, estimated serum levels of 20-25 pg/ml, 100-600 pg/ml, and 1-2 ng/ml, respectively). Animals were sacrificed at 3 weeks and MAO-A and -B activity was assessed in homogenates of heart, liver, lung, uterus, kidney, adrenal and small intestine using 5-hydroxytryptamine and phenylethylamine as substrates. Cortex, amygdala and hypothalamus were microdissected from frozen sections of the brain and were also assayed for MAO-A and -B activity. High dose estrogen (5 mg/pellet) significantly decreased MAO-B activity and resulted in lesser or insignificant changes in MAO-A activity, respectively in liver (-30%, +1%), kidney (-22%, -11%), and uterus (-57%, -35%) (p < 0.05). No significant changes in enzyme activity were observed in heart, adrenal, lung and small intestine. In brain, estrogen (5 mg/pellet) decreased MAO-A activity in the hypothalamus (-28%) and amygdala (-21%), with no significant change seen in MAO-B. Our results suggest that estrogen exerts a tissue-specific, differential regulation of MAO-A and -B activity.

Monoaminergic dysregulation on diestrus-2 and estrus through high emotional reactivity

Rats with great differences in emotional reactivity, during weighing and handling for vaginal smear screening were examined on diestrus-2 (DE-2), proestrus (PE), and estrus (E). Rats with high emotional reactivity (HR), interpreted as trait anxiety, had different serotonergic and dopaminergic profile in hypothalamus-preoptic area (HY-PA) and striatum (Str) and thymus weight lower than that found in rats with low emotional reactivity (LR). In HY-PA of rats with HR when compared to rats with LR, increased 5-hydroxyindoleacetic acid (5-HIAA), 5-HIAA/serotonin (5-HT) ratio, and 3,4-dihydroxyphenylacetic acid (DOPAC) and in Str increased DOPAC and DOPAC/dopamine (DA) ratio were found only on DE-2, paralleled by increased adrenal weight and decreased thymus weight. In Str, a significant effect of HR on 5-HIAA was found only on E, in parallel with increased 5-HT and decreased DOPAC and DOPAC/DA ratio when compared to rats with LR. The results suggest that activation of 5-HT and DA in HY-PA and DA in Str through HR is apparent only on DE-2 while, conversely, on E suppression of striatal DA it is apparent with 5-HT dysregulation. These findings might have some relevance to the predisposition of women with trait anxiety to premenstrual syndrome.

Contraception as prevention and therapy: sex steroids and the brain

The brain is one of the specific target tissues for sex steroid hormones. Estrogens, progestins and androgens are able to induce several effects in brain areas of the central nervous system (CNS), through the binding with specific receptors. Specific receptors for gonadal steroids have been identified in the amygdala, hippocampus, basal forebrain cortex, cerebellum, locus ceruleus, midbrain rafe nuclei, glial cells, pituitary gland, hypothalamus and central gray matter. At the hypothalamic level, the principal target for sex steroids is those neurons producing the pulsatile release of the gonadotropin releasing hormone (GnRH), localized in the mediobasal hypothalamus and the arcuate nucleus. The GnRH release depends on the complex and co-ordinated interrelationships among gonadal steroids, pituitary gonadotropins and neuroactive transmitters, such as the noradrenaline, dopamine, opioid peptides (beta-endorphin), acetylcholine, serotonin, gamma-aminobutyrric acid, corticotropin releasing hormone and neuropeptide Y. The interplay of these control mechanisms is governed by peripheral feedback signals; as well as the input from higher brain centers they may modify the GnRH secretion. The anterior pituitary lobe is the best known target tissue for endogenous or exogenous sex steroid hormones, because it is possible to detect luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels in blood, as the expression of the pituitary cells' activity. The synthesis and release of FSH and LH by the gonadotropic cells depend upon the peripheral control of gonadal hormones and the GnRH hypothalamic release. In summary, during a woman's reproductive life, the interaction between neurotransmitters, neuropeptides and gonadal hormones modulates the hypothalamo-pituitary-gonadal axis by acting selectively on the synthesis and release of GnRH and of pituitary gonadotropic hormones. The increased use of oral contraceptives in the last 30 years and, in general, of sex steroid hormone derivative therapies, has led to the study of the biochemical and metabolic properties of the different progestin molecules available in hormonal therapies by focusing attention on the interactions between estrogens and progestins in the modulation of the hypothalamo-pituitary-gonadal axis. The different kinds of estrogen and progestin molecules used in oral contraceptives inhibit the ovulatory process and may interfere with other sex steroid hormone receptors, thus exerting multiple effects in each target tissue.

Estrogen replacement therapy and cognitive function in postmenopausal women without dementia

The epidemiologic evidence for an association between estrogen and cognitive function among healthy postmenopausal women remains controversial. Equivocal findings may be explained, in part, by differences in the methodologic approaches of these studies. Overall, the evidence for a positive relationship comes primarily from randomized clinical trials. These trials suggest an acute effect on specific tests of recent verbal memory and tasks incorporating concept formation and reasoning. The potential long-term effects of estrogen in slowing or delaying the age-related decline in cognitive function require further study. More data are needed to determine the effects of estrogen replacement therapy on cognitive function, independent of changes in mood and depressive symptoms. In addition, evidence suggests that progesterone may mitigate the beneficial effects of estrogen on mood. Research should be undertaken to determine the interactive effects of estrogen and progesterone on cognitive function. Lastly, there should be continued investigation by both epidemiologic and basic neuroscientific studies to further elucidate the specific cognitive domains that may respond to estrogen.

Effects of estradiol on the serotonin secretion and turnover in the hypothalamus of male tilapia, Oreochromis mossambicus, in vitro

The effects of estradiol on the secretion and turnover of serotonin in the hypothalamic fragments of male tilapia, Oreochromis mossambicus, were studied using a static incubation system. The quantitative analysis of serotonin and its related metabolite, 5-hydroxyindoleacetic acid, were performed by high-performance liquid chromatography with electrochemical detection. The hypothalamic fragments were incubated with 17 beta-estradiol at a concentration of 2 x 10(-8), 8 x 10(-8), 2 x 10(-7), 4 x 10(-7), or 4 x 10(-6) g/ml. The low dose of estradiol, 2 x 10(-8) g/ml, had no effect on the concentration of serotonin and 5-hydroxyindoleacetic acid or serotonin turnover in the hypothalamic incubation media. The moderate doses of estradiol 8 x 10(-8) and 2 x 10(-7) g/ml, increased the concentrations of serotonin and 5-hydroxyindoleacetic acid in the hypothalamic incubation media, but had no effect on the serotonin turnover. The high doses of estradiol, 4 x 10(-7) and 4 x 10(-6) g/ml, did not alter the serotonin concentration in the hypothalamic incubation media, but increased the 5-hydroxyindoleacetic acid concentration and serotonin turnover. These results demonstrate that the moderate dose of estradiol increases the serotonin activity by increasing the serotonin concentration, whereas the high dose of estradiol increases the serotonin activity by increasing the ratio of 5-hydroxyindoleacetic acid and serotonin. However, the serotonin concentration is homeostatically maintained in the extracellular fluid of hypothalamus under the high dose of E2 treatment.

Is there a role for estrogen replacement therapy in the prevention and treatment of dementia?

Studies in experimental animal models provide a convincing rationale for a role for ERT in the treatment and prevention of dementia. These studies establish the role of estrogen in the regeneration and preservation of neuronal elements within the CNS that are analogous to those regions of the brain most sensitive to the neurodegenerative changes associated with AD. Furthermore, behavioral studies in these animals establish a correlation between the hormone dependent changes in the neuronal architecture and learning and memory. However, extrapolation of these studies to post-menopausal women must be done with caution. Surgical and natural loss of ovarian function does not result in a clinically relevant decline in cognitive function over the short term (1 to 2 decades) or ever in some women. The modest changes that are observed may relate to the hormone's effect on neurotransmitter levels or their receptors. Although Singh et al. noted changes in neurotransmitter concentrations 5 weeks after ovariectomy, changes in cognitive performance in their rat model did not become significant until 28 weeks after ovariectomy--the equivalent of approximately 2 decades of human life. Except for the familial forms of the disease, AD is rarely seen in the first 2 decades after the menopause. However, by the third decade after the menopause, 50% of women can be expected to manifest the histopathological changes of AD. Approximately half of these women are without clinical evidence of disease. Thus, the neurodegenerative process of AD probably precedes by many years the age of onset of the disease. We do not know what factors contribute to the selective neuronal injury which, over time, eventually leads to the neuronal loss and reduced synaptic density that result in the cognitive impairment of AD. At this time we can only speculate as to estrogen's role in modifying this process. Data from experimental animal models suggest that estrogen deficiency would selectively increase the vulnerability of estrogen-responsive neural elements, for example, the cholinergic neurons of the basal forebrain and hippocampus--offulnerability mediated perhaps by the reduced expression of neurotrophic factors, decreased clearance of the amyloid protein, and/or reduced cerebral blood flow that are associated with estrogen deficiency. The brain's ability to adapt to the neuronal loss by stimulating axonal and synaptic regeneration would also be impaired by estrogen deficiency as suggested by estrogen's ability to restore the synaptic density of lesioned brains of ovariectomized animals. Thus, estrogen deficiency, like the apolipoprotein E4 allele, can be considered not a cause of AD but one of perhaps several factors modifying the neuronal injury and loss leading to AD. The limited epidemiologic data and intervention trials currently available are consistent with this interpretation. Because of the urgency and enormity of the problem of dementia in our aging society, there would now appear to be sufficient reason to allocate the resources needed to conduct the appropriate clinical trials to determine estrogen's efficacy in both the treatment and prevention of this devastating condition. These trials are needed so that women and their physicians can adequately weigh the risks and benefits of hormone replacement for the treatment and, more importantly, the prevention of dementia.

Female menopause, hormone replacement therapy, and cognitive processes

OBJECTIVES

To give definitions of and to describe the research techniques for cognitive functions. Further, to describe the effect of female aging and hormone replacement therapy on cognitive functions.

METHODS

Literature search of pertinent publications and description of initial steps of own research projects.

CONCLUSIONS

Effect of aging and hormone replacement therapy on cognitive functions has been researched very insufficiently, and with conflicting conclusions. The best available information suggests that hormone replacement therapy might bring about considerable benefit in this regard, and be of advantage even in trying to prevent senile dementia.

Sex hormones and psychological functioning in postmenopausal women

Women who seek medical care around the time of menopause frequently report changes in one or more aspects of psychological functioning. The etiology of these symptoms is likely multifactorial and, undoubtedly, individual and sociocultural factors are important determinants. The known psychotropic properties of the sex hormones provide reason to believe that the drastic decrease in sex steroid production at menopause is also causally related to the development of psychological symptoms in some women. Indeed, prospective, controlled studies show that exogenous estrogen administered to postmenopausal women alleviates depressive symptoms in a dose-dependent manner. Second, accumulating evidence is beginning to suggest that estrogen helps to maintain verbal memory in aging women to the exclusion of effects on visual memory or on other cognitive functions. Finally, whereas exogenous estrogen is important for the integrity of genital tissues, it would now seem that testosterone is the hormone most critically implicated in the maintenance of libido, or sexual desire, in women just as it is in men.

Long-term in vivo desipramine or estrogen treatment fails to affect serotonin-induced outward current in hippocampal pyramidal cells of the rat

The effect of castration combined with either long-term treatment with the tricyclic antidepressant drug desipramine or the sex steroid 17 beta-estradiol on serotonin responses in area CA1 of the hippocampus of male and female rats was examined. Using single-electrode current and voltage-clamp techniques serotonin-induced hyperpolarizations and outward currents were recorded from hippocampal pyramidal cells. Neither in male nor in female castrated rats treatment effects were observed on the magnitude of the 5-hydroxytryptamine 1A mediated outward currents (0.26 nA) and membrane hyperpolarizations (11 mV) induced by superfusion of serotonin (15 microM), or on the effect of serotonin on the afterhyperpolarization and extracellularly recorded population spike. In voltage-clamp experiments using microelectrodes filled with potassium-chloride, but not with potassium-acetate, the sole observable effect was that the membrane resistance drop due to application of serotonin was significantly larger in the ovariectomized group (31% approximately 19 M omega) as compared to the ovariectomized/estrogen supplemented group (23% approximately 15 M omega). Spiperone (3 microM) completely antagonized the serotonin-induced outward currents and input resistance changes under all treatments. Apart from these changes the majority of passive and active membrane properties of cells from ovariectomized animals were not affected by chronic desipramine or steroid treatment. Neither did castration alone, nor in combination with long-term 17 beta-estradiol treatment, affect CA1 pyramidal cell membrane properties of male rats. Since we attained physiological levels of 17 beta-estradiol in the blood plasma (30-50 pg/ml) using subcutaneous silastic implants containing a mixture of cholesterol/estrogen, we conclude that both long-term estrogen and long-term desipramine treatment do not affect serotonergic neurotransmission in CA1 of the rat hippocampus.

Distribution of catecholamines in the central nervous system of the pig

The objective of this study was to document, through comprehensive means, normal distribution and concentration of catecholamines in various regions of the CNS of pigs, an increasingly popular animal model used for transgenic manipulation of neural genes. The effects of gonadal steroidal status on this distribution were also assessed by comparing CNS catecholamine concentrations among mature male pigs (boars), immature (gilts) and mature female pigs (sows), and adult male pigs castrated prepuberally (barrows). Dissected tissue samples from the CNS were extracted in 2 N acetic acid, filtered through a 0.2 micron filter, then quantitated by reverse-phase high performance liquid chromatography using a C-18 reverse phase column with electrochemical detection. In both boars and sows the highest concentrations of norepinephrine (NE) were found in the diencephalic areas and brain stem. Gilts exhibited elevated concentrations of NE in the olfactory bulbs (OB), hypothalamus, pons, and corpus trapezoideum-locus ceruleus (LC) compared to lower concentrations in corresponding areas of sows. Prepuberal castration of the male was associated with significantly lower NE concentrations in the striatum, periaqueductal area (PAG), pons, LC, and spinal cord. The sow exhibited significantly lower NE concentrations in the mammillary area (Mam), PAG, pons, and spinal cord than those in corresponding areas of the boar. Dopamine concentrations appeared to be similar in all areas of the brain and spinal cord studied in the sow and boar. Results demonstrated that prepuberal castration of the male appears to significantly alter the DA content of the Mam and dorsal spinal cord, in contrast to gilts who possess significantly higher concentrations of DA. It is concluded from our studies that in general, catecholamine concentrations in various regions of the brain and spinal cord of sexually mature pigs parallel distributions of neuropeptides, substance P, and methionine enkephalin, as previously reported. In addition, significant association was found between gonadal activity and catecholamine concentrations in discrete areas of the pig brain.

A review and reevaluation of the role of serotonin in the modulation of lordosis behavior in the female rat

The role of serotonin (5-HT) in the modulation of sexual receptivity (lordosis) in the female rat is reviewed and reevaluated. The effects on lordosis of drug treatments that decrease or increase the activity and availability of central 5-HT are first discussed, and this is followed by an evaluation of the effects of drugs that act directly at 5-HT receptors. In order to shed light on the physiological significance of effects of serotonergic drugs on lordosis, there is also a review of what is known of changes in levels of serotonergic activity and densities of 5-HT receptors in the female rat brain that take place through the estrous cycle and in response to administration of behaviorally effective doses of gonadal steroids. Serotonin has generally been thought to have a tonic, inhibitory effect on lordosis. However, it is concluded that 5-HT can either inhibit or facilitate lordosis depending on which subtypes of central 5-HT receptors become activated. Because of a lack of consistent or compelling evidence of effects of ovarian hormones on serotonergic activity or 5-HT receptors in critical areas of the brain, it is stated that there is at present no basis to conclude that the effects of pharmacological manipulations of serotonergic activity on lordosis reflect an important, physiological role of 5-HT in the modulation of lordosis behavior in the female rat.

Rat brain hypothalamic and hippocampal monoamine and hippocampal beta-adrenergic receptor changes during pregnancy

The concentration of noradrenaline (NA), dopamine (DA), serotonin (5-HT), and their metabolites was measured in hypothalamic and hippocampal brain tissue obtained from non-pregnant, 15- or 20-day pregnant and 4-day postpartum rats. At 20 days of pregnancy, hypothalamic NA and DA concentrations were significantly decreased and their turnover increased relative to postpartum and estrous values, respectively. Hippocampal 3-methoxy-4-hydroxy-phenylglycol (MHPG) levels were significantly decreased at 15 days of pregnancy and 4 days postpartum compared to estrous and 20-day pregnant levels and the MHPG/NA ratio was significantly reduced at 4 days postpartum relative to the estrous value. Hippocampal 5-HT and 5-hydroxyindole-3-acetic acid (5-HIAA) levels were significantly decreased at 15 days of pregnancy while 5-HIAA levels and the 5-HIAA/5-HT ratio were significantly decreased at 20 days of pregnancy. Hippocampal beta-adrenergic receptor density was significantly lower at 4 days postpartum than at 15 days of pregnancy. A positive correlation was observed between plasma progesterone and hippocampal beta-adrenoceptor Kd values, suggesting a possible causal relationship between these two variables. The monoamine and beta-adrenoceptor changes which occur during pregnancy may be an important contributing factor in determining the mood changes which occur during pregnancy and postpartum.

Changes in hypothalamic monoamine oxidase activity in relation to 17 beta-estradiol and clomiphene citrate treatments in the teleost Channa punctatus during three seasons

Hypothalamic monoamine oxidase (MAO) activity displayed biphasic responses to administration of estradiol-17 beta (E2) depending on season. Lower doses of 0.05 and 0.10 microgram/g BW of E2 had enhanced enzyme activity and higher doses (0.5 and 1.0 microgram/g BW) depressed it significantly in preparatory season. In prespawning phase, the lowest dose of 0.05 microgram/g BW of E2 was stimulatory and the higher doses were inhibitory to MAO activity. In postspawning season, lower doses (0.05 and 0.10 microgram/g BW) of E2 failed to elicit any significant change in enzyme activity whereas the higher doses (0.5 and 1.0 microgram/g BW) elevated it significantly. Administration of clomid (5, 10, and 20 micrograms/g BW) inhibited MAO activity in a dose-dependent manner during all the three seasons. The results show that E2 may participate in feedback control of gonadotropin secretion by modifying monoaminergic activity at the level of oxidative deamination by MAO.

Time-dependent effects of ovarian steroids on tyrosine hydroxylase activity in the limbic forebrain of female rats

In this work, we have studied the time-course of the effects of pharmacological administration of ovarian steroids on tyrosine hydroxylase (TH) activity in the limbic forebrain of ovariectomized rats. Administration of estradiol produced a late decrease in TH activity. This effect was found 24 hours after the last steroid injection, disappearing at 32 hours. It was antagonized by progesterone, since a single injection of this steroid to estradiol-pretreated rats reversed to control values the estradiol-induced decrease. Nevertheless, the administration of progesterone after estradiol treatment caused a short-time decrease in the limbic activity of TH, which was observed 4 hours after the last steroid injection, disappearing subsequently. On the other hand, the administration of progesterone alone produced a biphasic effect, with a reduction at 24 hours, followed by an increase at 32 hours. These effects were only observed in the animals non-treated with estradiol, disappearing with a previous treatment with estrogens. Hence, it can be concluded that both ovarian steroids may affect the limbic TH activity. Thus, estradiol produced a late inhibitory effect on the activity of this enzyme, which was antagonized by progesterone. Administration of the last one to estradiol-treated rats produced a short-time inhibitory effect, whereas its administration to non-treated rats produced a late biphasic effect (inhibition followed by stimulation), which was not observed in estradiol-treated rats.