The effect of progestins on behavioral stress responses in postmenopausal women

Review : Gonadal Steroids and Affective Illness

Gonadal steroids seem to regulate affective state in some people (but not all), despite the absence of abnormal steroid hormone levels or dysfunction of the reproductive endocrine axis. In this article, we attempt to explain this paradox 1) by describing the molecular mechanisms by which gonadal steroids can regulate neuronal function; 2) by describing the specific regulatory impact of gonadal steroids on two systems im plicated in the pathophysiology of mood disorders; and 3) by defining the role of gonadal steroids in several mood disorders linked to periods of reproductive change. We suggest that the context in which the neuro- regulatory actions of gonadal steroids occur determines the impact of steroid signaling on the regulation of affective state. NEUROSCIENTIST 5:227-237, 1999

Salivary cortisol and explicit memory in postmenopausal women using hormone replacement therapy

Circulating cortisol levels are known to influence explicit memory in humans and other primates. The present study investigated salivary cortisol and its association with explicit memory performance in 99 postmenopausal women (64 treated with conjugated equine estrogens or estradiol, and 35 matched controls not using any form of hormone therapy). Controls were compared with treated women taking estrogens alone (n=39), or taking estrogens in combination with a progestin (n=25). Mean time on hormone therapy was approximately 5 years, with initiation of treatment in close proximity to the onset of menopause. Explicit memory was assessed with the California Verbal Learning Test (CVLT). Saliva was collected before (basal or resting sample) and after (post-test sample) completing a set of cognitive tasks. Cortisol was measured using a high-sensitivity radioimmunoassay. Treated women were found to have higher resting cortisol concentrations than controls matched for time of day. Basal cortisol was a modest predictor of learning and memory on the CVLT. Higher cortisol was associated with better recall and fewer memory errors, which is consistent with experimental studies examining explicit memory under small increases in circulating cortisol load. Potential cumulative effects on the central nervous system of sustained exposure to mildly increased cortisol in conjunction with the long-term use of oral estrogens are discussed in the context of aging and dementia.

Sex, the brain and hypertension: brain oestrogen receptors and high blood pressure risk factors

Hypertension is a major contributor to worldwide morbidity and mortality rates related to cardiovascular disease. There are important sex differences in the onset and rate of hypertension in humans. Compared with age-matched men, premenopausal women are less likely to develop hypertension. However, after age 60, the incidence of hypertension increases in women and even surpasses that seen in older men. It is thought that changes in levels of circulating ovarian hormones as women age may be involved in the increase in hypertension in older women. One of the key mechanisms involved in the development of hypertension in both men and women is an increase in sympathetic nerve activity (SNA). Brain regions important for the regulation of SNA, such as the subfornical organ, the paraventricular nucleus and the rostral ventral lateral medulla, also express specific subtypes of oestrogen receptors. Each of these brain regions has also been implicated in mechanisms underlying risk factors for hypertension such as obesity, stress and inflammation. The present review brings together evidence that links actions of oestrogen at these receptors to modulate some of the common brain mechanisms involved in the ability of hypertensive risk factors to increase SNA and blood pressure. Understanding the mechanisms by which oestrogen acts at key sites in the brain for the regulation of SNA is important for the development of novel, sex-specific therapies for treating hypertension.

The effects of exogenous progesterone on drug craving and stress arousal in cocaine dependence: impact of gender and cue type

AIMS

Exogenous progesterone has been shown to attenuate the rewarding effects of cocaine. However, its effects on provoked drug craving, stress arousal and cognitive performance has not been systematically investigated in cocaine dependent men and women. Thus, we conducted a double-blind placebo-controlled study assessing the efficacy of progesterone in reducing provoked drug craving, stress system arousal and improving cognitive performance in cocaine dependent men and women.

METHODS

Forty-two early abstinent treatment-seeking cocaine dependent individuals were randomly assigned to either daily doses of placebo (12M/9F) or micronized progesterone (12M/9F) (400 mg/day), for 7 days. Under experimental conditions, all subjects were exposed to three 5-min personalized guided imagery conditions (stress, cocaine cue, relaxing), one per day, consecutively in a random, counterbalanced order. Subjective craving, mood, hypothalamic-pituitary-adrenal (HPA) and cardiovascular output, and a cognitive measure of inhibitory control (Stroop Color Word Task) were assessed pre- and post imagery.

RESULTS

Progesterone relative to placebo significantly decreased cue-induced craving and cortisol responses and increased cue-induced ACTH. In addition, women but not men receiving progesterone reported lower ratings of negative emotion and higher ratings of relaxed mood following stress exposure. Improved Stroop performance was observed in all participants receiving progesterone, across all conditions.

CONCLUSIONS

Progesterone was selectively effective in reducing cocaine cue-induced but not stress-related cocaine craving as well as specific measures of the provoked arousal state. Findings suggest that progesterone's effects on drug craving and arousal are moderated by both the type of environmental cue exposure and gender.

Biological sex and menstrual cycle phase modulation of cortisol levels and psychiatric symptoms in a non-clinical sample of young adults

Prior research examined the complex, bidirectional interplay of the hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal axes and their roles in (clinical) cognitive/behavioral functions. Less well understood are contemporaneous relationships in non-clinical samples. This pilot study explored cortisol in relation to psychiatric symptoms/personality as a function of self-reported menstrual cycle phase and sex differences in a non-clinical, young adult sample. Consistent with literature and hypotheses, cortisol levels were lowest during early-follicular, intermediary during late-follicular, and highest during mid-luteal phases (not significant), and greater among males than early-follicular females. An acute stressor uniformly affected cortisol across phases and sex, though magnitude and time course differed. Psychiatric symptoms were greater among early-follicular/late-follicular females versus males, and early-follicular and/or late-follicular versus mid-luteal. Contrary to hypotheses, positive psychotic-like symptoms were greater among males than (mid-luteal) females. Cortisol inversely related to early-follicular symptoms, and directly related to late-follicular/mid-luteal symptoms. Results suggest menstrual cycle phase modulates non-clinical psychiatric symptomatology and HPA activity. Findings tentatively bolster a dimensional/continuum model of psychopathology with implications for understanding neurobiological underpinnings and risk/protective factors for mental/physical health conditions, particularly those marked by sex differences and neuroendocrine dysfunction (depression/schizophrenia/Alzheimer's/multiple sclerosis). We speculate a dose-response cortisol effect on symptoms, modulated by endogenous gonadal hormones via gene expression.

In healthy young and elderly adults, hypothalamic-pituitary-adrenocortical axis reactivity (HPA AR) varies with increasing pharmacological challenge and with age, but not with gender

BACKGROUND

Hypothalamic-pituitary-adrenocortical axis reactivity (HPA AR) is the key indicator of the psychophysiological response to stress. The HPA AR may vary with age and gender. To investigate these factors concurrently, the aims of the present study were to observe HPA AR (plasma ACTH and plasma cortisol) in response to a pharmacological challenge (dexamethasone/corticotropin releasing hormone test: DEX/CRH-test) and as a function of age and gender.

METHOD

19 young (10 females and 9 males; mean age = 24.05 years) and 23 elderly (11 females and 12 males; mean age = 71.61 years) healthy volunteers took part in the study. To assess HPA AR, participants underwent the combined DEX/CRH test applied with the following DEX doses: 0.75, 1.5, and 3.0 mg, respectively.

RESULTS

A dose-dependent response was observed in young adult participants, but not in elderly participants. With increasing DEX doses, ACTH and cortisol values decreased in young adult participants, while the decrease was blunted among elderly compared to young adult participants. No differences were observed for gender.

CONCLUSIONS

Results point to diminished HPA axis sensitivity as an effect of normal aging, irrespective of gender. Therefore, altered HPA regulation in old age should be taken into account for developing new therapeutic approaches acting on the HPA axis and its receptor mechanisms.

Menstrual cycle modulation of medial temporal activity evoked by negative emotion

Previous studies have indicated phase-related differences in HPA activity and amygdala responsiveness in women, such that the response to negative emotional images is reduced during high-estrogen phases of the menstrual cycle. Other research has indicated an opposite effect of exogenous progesterone, increasing amygdala activity at some doses. However, no study to date has assessed the response of the brain's arousal circuitry to negative images during the luteal phase, when both progesterone and estrogen levels are elevated. To address this question, 17 naturally cycling women were each scanned during the early follicular and mid-luteal phases of the cycle, and response to IAPS images was assessed by fMRI. The results indicated significantly increased activity in hippocampus and amygdala during mid-luteal scans when compared to scans in the early follicular phase. These findings suggest that progesterone-mediated effects dominate during the luteal phase, and further suggest that estrogen and progesterone may play opposing roles in modulating the brain's arousal circuitry.

Sex differences in stress response circuitry activation dependent on female hormonal cycle

Understanding sex differences in stress regulation has important implications for understanding basic physiological differences in the male and female brain and their impact on vulnerability to sex differences in chronic medical disorders associated with stress response circuitry. In this functional magnetic resonance imaging study, we demonstrated that significant sex differences in brain activity in stress response circuitry were dependent on women's menstrual cycle phase. Twelve healthy Caucasian premenopausal women were compared to a group of healthy men from the same population, based on age, ethnicity, education, and right handedness. Subjects were scanned using negative valence/high arousal versus neutral visual stimuli that we demonstrated activated stress response circuitry [amygdala, hypothalamus, hippocampus, brainstem, orbitofrontal cortex (OFC), medial prefrontal cortex (mPFC), and anterior cingulate gyrus (ACG)]. Women were scanned twice based on normal variation in menstrual cycle hormones [i.e., early follicular (EF) compared with late follicular-midcycle (LF/MC) menstrual phases]. Using SPM8b, there were few significant differences in blood oxygenation level-dependent (BOLD) signal changes in men compared to EF women, except ventromedial nucleus (VMN), lateral hypothalamic area (LHA), left amygdala, and ACG. In contrast, men exhibited significantly greater BOLD signal changes compared to LF/MC women on bilateral ACG and OFC, mPFC, LHA, VMN, hippocampus, and periaqueductal gray, with largest effect sizes in mPFC and OFC. Findings suggest that sex differences in stress response circuitry are hormonally regulated via the impact of subcortical brain activity on the cortical control of arousal, and demonstrate that females have been endowed with a natural hormonal capacity to regulate the stress response that differs from males.

Sex differences in drug-related stress-system changes: implications for treatment in substance-abusing women

Extensive research indicates that chronic substance abuse disrupts stress and reward systems of the brain. Gender variation within these stress-system alterations, including the impact of sex hormones on these changes, may influence sex-specific differences in both the development of, and recovery from, dependency. As such, gender variations in stress-system function may also provide a viable explanation for why women are markedly more vulnerable than men to the negative consequences of drug use. This article therefore initially reviews studies that have examined gender differences in emotional and biophysiological changes to the stress and reward system following the acute administration of drugs, including cocaine, alcohol, and nicotine. The article then reviews studies that have examined gender differences in response to various types of stress in both healthy and drug-abusing populations. Studies examining the impact of sex hormones on these gender-related responses are also reported. The implications of these sex-specific variations in stress and reward system function are discussed in terms of both comorbid psychopathology and treatment outcome.

Why do we respond so differently? Reviewing determinants of human salivary cortisol responses to challenge

Stress and stress-related health impairments are major problems in human life and elucidating the biological pathways linking stress and disease is of substantial importance. However, the identification of mechanisms underlying a dysregulation of major components of the stress response system is, particularly in humans, a very challenging task. Salivary cortisol responses to diverse acute challenge paradigms show large intra- and interindividual variability. In order to uncover mechanisms mediating stress-related disorders and to potentially develop new therapeutic strategies, an extensive phenotyping of HPA axis stress responses is essential. Such a research agenda depends on substantial knowledge of moderating and intervening variables that affect cortisol responses to different stressors and stimuli. The aim of this report is, therefore, to provide a comprehensive summary of important determinants of, in particular, human salivary cortisol responses to different kinds of laboratory stimuli including acute psychosocial stress as well as pharmacological provocation procedures. This overview demonstrates the role of age and gender, endogenous and exogenous sex steroid levels, pregnancy, lactation and breast-feeding, smoking, coffee and alcohol consumption as well as dietary energy supply in salivary cortisol responses to acute stress. Furthermore, it briefly summarizes current knowledge of the role of genetic factors and methodological issues in terms of habituation to repeated psychosocial stress exposures and time of testing as well as psychological factors, that have been shown to be associated with salivary cortisol responses like early life experiences, social factors, psychological interventions, personality as well as acute subjective-psychological stress responses and finally states of chronic stress and psychopathology.

Estrogen administration negatively alters mood following monoaminergic depletion and psychosocial stress in postmenopausal women

Differences in the rates of affective disorders between women and men may relate to gender differences in gonadal steroid levels such as estrogen that have effects on brain monoamines important to mood regulation. Changes in estrogen secretion patterns during the perimenopause and menopause may be relevant to the increased risk for affective symptoms at that time. This study examined whether 17beta-estradiol (E2) administration can modify the mood effects of experimental psychosocial stress following acute monoamine depletion in postmenopausal women. Subjects consisted of 15 normal postmenopausal women (PMW) (ages 67.1+/-11.2 years) blindly placed on either oral placebo or E2 (1 mg/day for 1 month, then 2 mg/day for 2 months). At the end of the 3-month treatment phase, subjects participated in three blinded depletion challenges in which they ingested each of three amino-acid mixtures: deficient in tryptophan, deficient in phenylalanine/tyrosine, or nutritionally balanced. After 5 h, subjects performed the Trier Social Stress Test (TSST), followed by mood and anxiety ratings. E2-treated subjects exhibited a significant increase in negative mood and anxiety after the TSST compared to placebo-treated women. These effects were independent of monoamine depletion and were not manifest before the TSST or at baseline. Exogenous estrogen administration in PMW may alter or modulate emotional reactivity to stressful events and may alter the sensitivity of emotional regulation. This modulation appears to be independent of alterations in monoaminergic neurotransmission. The dose of estrogen used after menopause may be important in determining the effects of gonadal steroids on emotional regulation.

Sex, hormones and affective arousal circuitry dysfunction in schizophrenia

Women with schizophrenia express affective disturbances disproportionately more than men. Brain regions implicated in the affective arousal circuitry also regulate the hypothalamic-pituitary-adrenal and -gonadal systems, which are dysfunctional in schizophrenia. This review will argue that understanding the etiology of affective arousal deficits in schizophrenia is intimately connected with characterizing the role of neuroendocrine dysfunction and sex effects in schizophrenia. Further, the etiology of these neuroendocrine deficits begins during fetal development, during a period of time that coincides with the sexual differentiation of the brain and the vulnerability for schizophrenia. Studying the links between deficits in neuroendocrine systems and the affective arousal system in schizophrenia will provide clues to understanding the development of sex differences in schizophrenia and thereby its etiology.

Hormonal cycle modulates arousal circuitry in women using functional magnetic resonance imaging

Sex-specific behaviors are in part based on hormonal regulation of brain physiology. This functional magnetic resonance imaging (fMRI) study demonstrated significant differences in activation of hypothalamic-pituitary-adrenal (HPA) circuitry in adult women with attenuation during ovulation and increased activation during early follicular phase. Twelve normal premenopausal women were scanned twice during the early follicular menstrual cycle phase compared with late follicular/midcycle, using negative valence/high arousal versus neutral visual stimuli, validated by concomitant electrodermal activity (EDA). Significantly greater magnitude of blood oxygenation level-dependent signal changes were found during early follicular compared with midcycle timing in central amygdala, paraventricular and ventromedial hypothalamic nuclei, hippocampus, orbitofrontal cortex (OFC), anterior cingulate gyrus (aCING), and peripeduncular nucleus of the brainstem, a network of regions implicated in the stress response. Arousal (EDA) correlated positively with brain activity in amygdala, OFC, and aCING during midcycle but not in early follicular, suggesting less cortical control of amygdala during early follicular, when arousal was increased. This is the first evidence suggesting that estrogen may likely attenuate arousal in women via cortical-subcortical control within HPA circuitry. Findings have important implications for normal sex-specific physiological functioning and may contribute to understanding higher rates of mood and anxiety disorders in women and differential sensitivity to trauma than men.

Naloxone does not influence cardiovascular responses to mild mental stress in postmenopausal women

The interaction between central opioid activity, sex hormones, and the cardiovascular reactivity to stress is unknown. Twenty-eight healthy postmenopausal women, 16 without, and 12 with hormone replacement therapy (HRT) participated in this randomized, double-blind, cross-over study. The opioid receptor antagonist naloxone or placebo was administered intravenously on 2 different days and mild mental stress was induced by the Stroop Color-Word Test. Cardiovascular responses were assessed noninvasively by impedance cardiography. Stress significantly increased stroke volume, cardiac output, blood pressure, and heart rate, which was not influenced by opioid receptor blockade. Whereas naloxone increased cortisol plasma concentrations irrespective of HRT status, luteinizing hormone concentrations, which were higher in non-HRT compared with HRT women, were increased by naloxone in women with HRT only. These data suggest that the opioidergic tone of the hypothalamus-pituitary-adrenal axis persists in postmenopausal women, irrespective of HRT use, while the opioidergic tone on the hypothalamus-pituitary-gonadal axis seems to depend on an estrogenic milieu. Naloxone does not alter cardiovascular mental stress reactions in postmenopausal women independent of their hormone substitution status.

Influence of hormone therapy on the cardiovascular responses to stress of postmenopausal women

Epidemiological and psychophysiological data suggest that groups that differ in reproductive hormones and stress responses also differ in risk for cardiovascular disease. To evaluate the effects of hormone therapy on women's cardiovascular responses to laboratory stressors, 89 healthy postmenopausal women were tested twice, before and after exposure for about 8 weeks to one of the five conditions: placebo, Estratab (primarily estrone), Estratab plus Prometrium (micronized progesterone), Estratab plus Provera (synthetic progestin), and Estratest (same estrogen as in Estratab plus methyltestosterone). Results showed that women assigned to Estratab plus Prometrium and Estratest had diminished systolic blood pressure responses to stress upon retesting, whereas the other groups did not change in the level of their responses. Women assigned to Estratab plus Prometrium had diminished diastolic blood pressure responses during a speech stressor upon retesting, whereas women assigned to Estratab plus Provera increased. Our findings show that hormone therapy does affect women's stress responses, but they do not provide a simple explanation as to why groups at high and low risk for cardiovascular disease differ in reproductive hormones and stress responses.

Reactivity of immune, endocrine and cardiovascular parameters to active and passive acute stress

This study clarified associations among immune, autonomic, and endocrine activities during mental arithmetic and cold pressor stress tasks in 26 women in the follicular phase. Both tasks decreased CD3+ T cells, CD4+ T cells, and CD19+ B cells, whereas they increased lymphocytes, granulocytes, NK cells, and NK cell activity (NKCA). The mental arithmetic task had a greater impact than the cold pressor task on changes in CD3+ T cells and in NK cells. Cardiovascular reactivity to active stress was associated with increased NK cells and decreased CD3+ T cells. Reduced cortisol levels during passive stress were associated with decreased CD19+ B cells and with increased NK cells. The merits of this study are that it controlled the following factors. Perceived stress during the two tasks was matched; both tasks lasted long enough to elicit high-magnitude responses; and the length of the intervening rest period minimized probable carryover effects between tasks.

Hormone replacement in postmenopausal women: impact of progestogens on autonomic tone and blood pressure regulation

OBJECTIVE

Depressed heart rate variability (HRV) reflects an imbalance of autonomic tone and independently predicts increased cardiovascular risk in patients with congestive heart failure or after acute myocardial infarction. While hormone replacement therapy (HRT) with estrogens beneficially modulates autonomic tone and blood pressure (BP) regulation in postmenopausal women, the impact of concomitant treatment with progestogens remains unclear.

DESIGN

In this cross-sectional study, HRV and BP were examined in 62 healthy women (ages 48-71 years) using digital beat-to-beat interval recordings of heart rate and 24-hour ambulatory BP measurements.

RESULTS

Demographic parameters did not differ among women without HRT (n = 23), on estrogen (n = 17; ERT), or on progestogen-estrogen containing HRT (n = 22; PERT). Total power of HRV was significantly lower, whereas mean heart rate (HR) was significantly higher among women on PERT group versus controls and ERT (total power: 1611 +/- 146 vs. 2497 +/- 308 and 2472 +/- 348 ms(2); heart rate: 80.7 +/- 1.2 vs. 75.0 +/- 1.4 and 74.0 +/- 2.2 bpm; p < 0.05). In addition, low-frequency power and time-dependent parameters of HRV were lower among women on PERT group versus controls and ERT (p < 0.05). ERT use was associated with reduced systolic and diastolic daytime BP, whereas no significant differences were evident PERT users compared with controls.

CONCLUSIONS

Progestogen-containing replacement therapy was associated with increased HR and an attenuation of HRV in postmenopausal women. BP was lower in women on ERT, whereas this effect was offset in the PERT group. These observations could at least partially explain the ambiguous results of progestogen-containing HRT on cardiovascular risk in the Heart and Estrogen/Progestin Replacement Study (HERS).

Gender differences in age-related changes in HPA axis reactivity

Possible differences between men and women in age-related patterns of hypothalamic-pituitary-adrenal (HPA) axis response to challenge were examined to test the hypothesis that women show greater age-related increase in HPA axis reactivity to challenge. Twenty-six younger subjects, 9 men and 17 women, ages 22-26 and 14 older subjects, 7 men and 7 women, ages 67-88 participated in the study. Patterns of change in salivary "free" cortisol were measured in response to a standardized, 30-minute cognitive challenge, administered individually to each subject beginning at 1600 h. Consistent with previous research, there was a significant main effect for age with respect to baseline cortisol: older age was associated with higher baseline cortisol (P = <0.001). Results also provide support for the hypothesized age-by-gender interaction with respect to patterns of response to challenge. There was a significant interaction with respect to maximum percentage increase over baseline (P < 0.002): among younger adults, the men exhibited greater increases whereas among the older adults, the women exhibited greater increases. A similar, though only marginally significant pattern was seen for total area under the response curve (P = 0.07). Repeated measures ANOVA confirmed the gender-by-age differences in the patterns of response (P = 0.01 for time*age*gender interaction).

Effects of chronic oestrogen replacement on stress-induced activation of hypothalamic-pituitary-adrenal axis control pathways

Oestrogen replacement therapy reportedly suppresses hypothalamic-pituitary-adrenal (HPA) axis responses to an emotional stressor in postmenopausal women. However, most studies in the rat suggest a facilitatory role for oestrogen in the control of HPA axis function. One explanation for this difference may be the regimen of oestrogen replacement: during oestrogen replacement therapy, oestrogen levels are low and constant whereas most animal studies examined the HPA axis response when oestrogen levels are rising. In the present study, we assessed HPA axis stress responses in mature ovariectomized rats after plasma oestrogen levels had been maintained at physiological levels for a prolonged period (25 or 100 pg/ml for 7 days). In the case of both an emotional stressor (noise) and a physical stressor (immune challenge by systemic interleukin-1beta administration), oestrogen replacement suppressed stress-related Fos-like immunolabelling, in hypothalamic neuroendocrine cells and plasma adrenocorticotropin hormone responses. From the present data, and past reports, it appears unlikely that these effects of oestrogen are due to a direct action on corticotropin-releasing factor or oxytocin cells. Therefore, to obtain some indication of oestrogen's possible site(s) of action, Fos-like immunolabelling was mapped in the amygdala and in brainstem catecholamine groups, which are neuronal populations demonstrating substantial evidence of involvement in the generation of HPA axis stress responses. In the amygdala, oestrogen replacement suppressed central nucleus responses to immune challenge, but not to noise. Amongst catecholamine cells, oestrogen replacement was more effective against responses to noise than immune challenge, suppressing A1 and A2 (noradrenergic) and C2 (adrenergic) responses to noise, but only A1 responses to immune challenge. These data suggest that, as in postmenopausal women on oestrogen replacement therapy, chronic low-level oestrogen replacement can suppress HPA axis stress responses in the rat. Moreover, oestrogen appears to exert effects at multiple sites within putative HPA axis control pathways, even though most of the relevant neuronal populations do not contain genomic receptors for this gonadal steroid and the pattern of oestrogen action differs for an emotional vs a physical stressor.

Hypothalamic pituitary adrenocortical and sympathetic nervous system responses to the cold pressor test in Alzheimer's disease

BACKGROUND

Increased basal activity of the hypothalamic-pituitary-adrenocortical (HPA) axis has been repeatedly demonstrated in Alzheimer's disease (AD), and some studies suggest increased basal activity of the sympathetic nervous system (SNS) in this disorder; however, the effects of AD on HPA axis or SNS responses to a standardized aversive stressor have not been examined. The neuroendocrine response to aversive stress may be relevant to the pathophysiology of AD.

METHODS

Plasma adrenocorticotropic hormone (ACTH), cortisol, norepinephrine (NE), and epinephrine responses to a 1-min cold pressor test (CPT) were measured in nine medically healthy AD outpatients (age 76 +/- 2 years) and nine age- and gender-matched medically healthy cognitively normal older subjects (age 76 +/- 1 year).

RESULTS

The cortisol response to CPT was increased in the AD group but the ACTH response did not differ between groups. Basal NE concentrations were higher in the AD group. Although NE responses to CPT did not differ between groups, the blood pressure response to CPT was higher in the AD subjects.

CONCLUSIONS

These results suggest increased HPA axis responsiveness to CPT at the level of the adrenal cortex in AD. The results also suggest increased basal sympathoneural activity and increased cardiovascular responsiveness to sympathoneural stimulation in AD under the conditions of this experimental protocol. Increased SNS stimulatory modulation of the adrenal cortex is a possible mechanism contributing to the observed enhanced cortisol response to CPT in these AD subjects.

Impact of gender, menstrual cycle phase, and oral contraceptives on the activity of the hypothalamus-pituitary-adrenal axis

OBJECTIVE

Results from animal and human studies suggest that disregulations of the hypothalamus-pituitary-adrenal (HPA) axis are involved in several behavioral, circulatory, endocrine, and immune disorders with clear-cut gender differences in disease prevalence. The aim of the present study was to investigate sex-specific HPA response patterns with a focus on the contribution of gonadal steroids as possible mediators.

METHODS

A total of 81 healthy adults were investigated in the present study. Twenty men, 19 women in the follicular phase of the menstrual cycle, 21 women in the luteal phase, and 21 women using oral contraceptives (OC) were exposed to a brief psychosocial stress test (Trier Social Stress Test; TSST) and injected with 0.25 mg ACTH1-24 on consecutive days. Basal HPA activity was investigated by repeatedly measuring cortisol levels immediately after awakening, as well as in 30-minute intervals from 9:00 AM to 9:00 PM. Additionally, questionnaires were used to assess psychological state and trait parameters.

RESULTS

Results show that the TSST induced significant increases in ACTH, salivary-free cortisol, total plasma cortisol, and heart rates, as well as increased wakefulness and reduced calmness in the total group. Significant group differences emerged for ACTH and salivary-free cortisol stress responses: Although men showed higher ACTH responses to the TSST compared with each of the three groups of women, salivary cortisol responses showed the following response pattern: Luteal = Men > Follicular = OC. The salivary cortisol responses to ACTH1-24 showed a similar response pattern: Luteal > Men > Follicular > OC. In contrast, total blood cortisol levels did not reveal any group difference between sexes or follicular versus luteal phase in either test. Although a similar salivary-free cortisol increase after awakening was found in the four groups, the circadian cortisol profile was significantly different throughout the first 4 hours of sampling. Questionnaire-derived psychological variables, as measured in the present study, could not explain the observed results.

CONCLUSIONS

We conclude that gender, menstrual cycle phase, and OC use exert important effects on HPA responsiveness to psychosocial stress in healthy subjects. Although men seem to have a stronger hypothalamic drive in response to stressful stimulation than women, differences in salivary-free cortisol levels, at least in part, may be explained by estradiol-induced changes in corticosteroid-binding protein levels. ACTH and cortisol secretion is not affected by OC use per se but the amount of bioavailable unbound cortisol ("free") is greatly reduced in this group of women after stimulation. Inasmuch as none of these differences between the study groups emerged in total blood cortisol levels, we strongly advocate for the simultaneous measurement of free and total cortisol levels in future studies on HPA functioning.