Sex differences in HPA axis responses to stress: a review

The impact of treatment on HPA axis activity in unipolar major depression

Dysregulation of hypothalamic-pituitary-adrenal axis activity in major depressive disorder has been found to normalize with successful treatment, though inconsistencies exist. To determine the magnitude of change in cortisol levels from pre to post-treatment in individuals with unipolar depression quantitative methods of meta-analysis were applied. Thirty-four studies met inclusion criteria and consisted of a total of 1049 depressed patients across study samples. The overall mean effect size of pre-post-treatment cortisol measures indicated that approximately 56% of depressed participants had similar cortisol levels before and after treatment regardless of symptom improvement. The mean effect size of pre-post cortisol measures for those who responded to treatment was larger than the mean effect size of non-responders; however, this difference did not reach statistical significance. As well, no significant differences in mean effect size of pre-post cortisol measures based on type of treatment (e.g. antidepressant vs. ECT) were found. Subtype of depressive illness and length of treatment may contribute to the magnitude of change in cortisol measure before and after treatment. Inconsistent findings within the reviewed literature may confound the overall results. The type of treatment and response to treatment do not appear to impact the magnitude of change in cortisol level pre to post-treatment. Our findings suggest that the utility of cortisol as an outcome measure may be limited to specific subsets of the depressed population, and that given the variability in HPA results between studies, it is premature to state that cortisol is not a good outcome measure.

Cardiovascular, hormonal, and emotional responses to the TSST in relation to sex and menstrual cycle phase

The prevalence of stress disorders differs between men and women. An understanding of how men and women vary in acute stress responses may help to understand these sex differences. We compared responses to the TSST and a control task in healthy men (N=28) and women tested in two phases (Follicular N=29, Luteal N=23) of the menstrual cycle. Men exhibited greater cortisol responses to stress than women in either phase. Luteal women exhibited the greatest subjective and allopregnanolone responses to stress, whereas follicular women exhibited blunted noradrenaline responses. Partial correlations controlling for group differences revealed that individuals who were most sensitive to the subjective effects of stress exhibited the largest salivary cortisol, noradrenaline, and allopregnanolone responses and the smallest progesterone responses to stress. We discuss our findings in the context of sex differences in the prevalence of stress-linked disorders.

The association between serum cortisol and cognitive decline in older persons

OBJECTIVE

To investigate whether serum cortisol levels are associated with cognitive performance and cognitive decline in elderly persons and whether this association differs by age, sex, and depression status.

DESIGN

Data from the Longitudinal Aging Study Amsterdam, with repeated measurements of cognitive performance after 3 and 6 years.

PARTICIPANTS

A total of 1,154 persons, aged 65-88 years.

MEASUREMENTS

Serum concentrations of total cortisol (CRT) and corticosteroid binding globulin (CBG) were measured at baseline, and from these free cortisol index (CRT/CBG) was computed. At baseline and 3 and 6 years of follow-up, global cognitive functioning, verbal memory performance, and speed of information processing were assessed.

RESULTS

After adjustment for demographics, health, and life style variables, a significant association between high levels of free cortisol and poorer performance on verbal learning (B = -0.32; 95% confidence interval: -0.64 to -0.01) was found in both women and men. Additional adjustment for depression did not change this association. In women, but not in men, high levels of free cortisol (B = -0.85; 95% confidence interval: -1.40 to -0.31) were associated with slower speed of information processing. The associations between cortisol and cognitive performance were the same for the younger and the older old and for depressed and nondepressed persons. Higher levels of cortisol were not associated with cognitive decline over a period of 6 years.

CONCLUSION

Our study provides further evidence that high levels of cortisol measured during the day are associated with lower memory function and speed of information processing but not with decline in cognitive functioning over 6 years of time.

Human models in acute and chronic stress: assessing determinants of individual hypothalamus-pituitary-adrenal axis activity and reactivity

Stress is one of the most significant health problems in modern societies and the 21st century. This explains a pressing need for investigations into the biological pathways linking stress and health. Besides the locus coeruleus-noradrenaline/autonomic (sympathetic) nervous system ( Chrousos and Gold 1992 ), the hypothalamus-pituitary-adrenal (HPA) axis is the major physiological stress response system in the body. Since alterations in HPA axis regulation under basal conditions and in response to acute stress appear to be a close correlate or even a determining factor of the onset of different diseases or disease progression ( Holsboer 1989 ; Chrousos and Gold 1992 ; Tsigos and Chrousos 1994, 2002 ; Stratakis and Chrousos 1995 ; McEwen 1998 ; Heim et al. 2000a ; Raison and Miller 2003 ), the characterization of an individual's HPA axis activity as well as reactivity pattern to psychosocial stress appears to be of major interest. It is obvious that such a research agenda substantially depends on the availability of appropriate measures. However, since the HPA axis is a highly adaptive system which is characterized by marked inter- and intraindividual variability ( Mason 1968 ; Hellhammer et al. 2009 ), the development of such markers of HPA axis regulation in humans was-and still is-a rather challenging task. In this brief review, we focus on findings on two HPA axis measures, namely the cortisol-awakening response (CAR) to assess HPA axis basal activity and the Trier social stress test (TSST) to investigate HPA axis stress reactivity.

Medial prefrontal cortex damage affects physiological and psychological stress responses differently in men and women

The ability to produce appropriate physiological and psychological responses to stressful situations depends on accurate recognition and appraisal of such situations. Such ability is also important for proper emotion regulation. A number of studies have suggested that the medial prefrontal cortex (mPFC) plays a significant role in emotion regulation, as well as in the control of physiological endpoints of emotion regulation such as the hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS). Further, recent work has suggested that men and women may differ in these mechanisms of neural control of emotion regulation. Here, we examined the role of the human mPFC in self-report, ANS, and HPA stress reactivity by testing a group of participants with damage to this region (9 women and 9 men), a brain damaged comparison group (6 women and 6 men), and healthy comparison participants (27 women and 27 men) on an orthostatic challenge and the Trier Social Stress Test (TSST). The mPFC participants showed heightened self-reported stress in response to the TSST. In women, mPFC damage led to an increased cortisol response to the TSST. By contrast, in men, greater volume of mPFC damage was correlated with a decreased cortisol response. Finally, men with mPFC damage showed altered autonomic control of the heart (higher heart rate and lower high frequency heart rate variability) during an orthostatic challenge. These findings support the idea that the mPFC is involved in the regulation of physiological and psychological responses to stress and that this regulation may differ between men and women.

Blood lead (Pb) levels: further evidence for an environmental mechanism explaining the association between socioeconomic status and psychophysiological dysregulation in children

OBJECTIVE

The authors recently reported that blood lead (Pb) was a significant mediator for the positive association between socioeconomic status (SES) and peripheral vascular responses to acute stress in children (B. B. Gump et al., 2007). The present study considers the possibility that Pb may also mediate an association between SES and cortisol responses to acute stress.

DESIGN

Early childhood Pb exposure was tested as a mediator for cross-sectional associations between SES and cortisol responses.

MAIN OUTCOME MEASURES

The primary outcome was cortisol responses to acute stress in 9.5-year-old children (N = 108).

RESULTS

Lower family income was associated with significantly greater cortisol levels following an acute stress task. A mediational analysis confirmed that Pb was a significant mediator for this association.

CONCLUSION

These results reaffirm the importance of considering the chemical environment as well as social and psychological environment when evaluating psychophysiological effects of low SES.

Sex-specific expression of BDNF and CART in the midbrain non-preganglionic Edinger-Westphal nucleus in the rat

In mammals, females generally appear more vulnerable to stressors than males. The non-preganglionic Edinger-Westphal nucleus (npEW) has been implicated in regulation of the stress response. Brain-derived neurotrophic factor (BDNF) and cocaine- and amphetamine-related transcript peptide (CART) are sex-specifically involved in the stress response too, and are present in the human and rat npEW. We hypothesized that male and female rats would differ in the expression of BDNF and CART in the npEW. Using immunocytochemistry and in situ hybridization we found that BDNF, CART and the estrogen receptor beta (ERbeta) are colocalized in the npEW. Q-RT-PCR showed no differences in CART and BDNF coding mRNAs between males and females, but quantitative immunocytochemistry revealed a 16% lower number of BDNF-immunoreactive neurons, and 19% lower CART-immunoreactivity in females compared to males. Considering the fact that Ucn1, CART and BDNF are co-expressed in the npEW with ERbeta and their protein expression differs between males and females, we propose that the functioning of the npEW may contribute to the sex differences that exist in stress sensitivity.

The neurobiology of psychopathy: a neurodevelopmental perspective

We provide an overview of the neurobiological underpinnings of psychopathy. Cognitive and affective-emotional processing deficits are associated with abnormal brain structure and function, particularly the amygdala and orbitofrontal cortex. There is limited evidence of lower cortisol levels being associated with psychopathic personality. Initial developmental research is beginning to suggest that these neurobiological processes may have their origins early in life. Findings suggest that psychopathic personality may, in part, have a neurodevelopmental basis. Future longitudinal studies delineating neurobiological correlates of the analogues of interpersonal-affective and antisocial features of psychopathy in children are needed to further substantiate a neurodevelopmental hypothesis of psychopathy.

Stress and decision-making in humans: performance is related to cortisol reactivity, albeit differently in men and women

Acutely elevated levels of cortisol are associated with euphoria and reward-like properties related to sensation-seeking behaviour. Thus, acute stress and elevated levels of cortisol may promote risk-taking behaviour. High cortisol responders are more sensitive to immediate rewards than low cortisol responders. In this study we therefore tested whether acute stress in male and female subjects, induced by the Trier Social Stress Test (TSST), affects decision-making as measured by the Iowa Gambling Task (IGT) and to what extent this is related to cortisol reactivity. Control subjects did not receive the stress manipulation. We specifically predict that high responders show risk-taking behaviour in the IGT compared to low responders and controls. The data show that the more (salivary) cortisol levels are elevated after the TSST the poorer the subsequent performance in the IGT in male subjects. In female subjects an inverse relationship between cortisol levels and IGT performance is observed: slightly elevated levels of cortisol after the TSST improve IGT performance, while highly elevated levels decrease IGT performance. Thus, acute stress as induced by the TSST affects decision-making behaviour of men and women differently and cortisol reactivity is associated with decision-making performance.

Polymorphism of the serotonin transporter gene modulates brain and physiological responses to acute stress in Japanese men

A short (S) variant, compared to a long (L) variant, of the promoter region of the serotonin transporter gene-linked polymorphic region (5HTTLPR) has been related to emotional hyper-reactivity. We tested whether the 5HTTLPR could modulate acute stress responses in the brain and, the cardiovascular and neuroendocrine systems. Ten Japanese male participants carrying double copies of the S alleles and 10 Japanese males carrying S and L alleles conducted a mental arithmetic task, and their regional cerebral blood flow by (15)O positron emission tomography and cardiovascular and neuroendocrine parameters were measured. During the acute stress task, the participants with the SS alleles showed stronger reactivity in blood pressure and secretion of epinephrine, compared to the participants with the SL and LL alleles. Furthermore, the SS carriers showed greater activation in stress-related brain regions such as the hypothalamus, cerebellum, midbrain, and pulvinar compared to the SL and LL carriers during the acute stress task. The present findings indicated that the S allele of the 5HTTLPR is associated with greater brain and physiological reactivity to acute stress in Japanese men.

Sex-specific dissociations in autonomic and HPA responses to stress and cues in alcohol-dependent patients with cocaine abuse

AIMS

Chronic alcohol and drug dependence leads to neuroadaptations in hypothalamic-pituitary-adrenal (HPA) and sympathetic adrenal medullary (SAM) stress systems, which impact response sensitivity to stress and alcohol cue and facilitates risk of relapse. To date, gender variations in these systems have not been fully assessed in abstinent alcohol-dependent individuals who also met criteria for cocaine abuse.

METHODS

Forty-two (21 M/21 F) early abstinent treatment-seeking substance-abusing (SA) men and women and 42 (21 M/21 F) healthy control (HC) volunteers were exposed to three 5-min guided imagery conditions (stress, alcohol/drug cue, neutral relaxing), presented randomly, one per day across three consecutive days. Alcohol craving and anxiety ratings were obtained as well as measures of heart rate (HR), blood pressure, plasma ACTH, cortisol, norepinephrine (NE) and epinephrine (EPI).

RESULTS

SA males showed increased ACTH and EPI basal tone compared with HC males and SA females. However, they demonstrated no increase in ACTH and cortisol levels following stress and alcohol cue imagery exposure compared to the neutral condition. SA females demonstrated a typically increased stress response in both measures. In addition, SA males showed no increase in cardiovascular response to either stress or cue, and no increase in catecholamine response to cue compared with their response to neutral imagery. Again, this dampening was not observed in HC males who produced significantly higher levels of cue-related HR and EPI, and significantly higher stress-related DBP. In contrast, SA females showed an enhanced ACTH and cortisol response to stress and cue compared with neutral imagery and this was not observed in the HC females. They also demonstrated a reduced increase in NE and EPI compared with both SA males and HC females as well as reduced HR compared with HC females.

CONCLUSIONS

While SA males showed a generalized suppression of HPA, SAM system and cardiovascular markers following both stress and cue, SA women demonstrated a selective sympatho-adrenal suppression to stress only and an enhanced HPA response to both stress and cue. These gender variations are discussed in terms of their potential impact on relapse vulnerability and treatment outcome.

The role of childhood abuse in HPA-axis reactivity in Social Anxiety Disorder: a pilot study

BACKGROUND

Studies on depression have found that childhood abuse (CA) is associated with a persistent sensitization of the hypothalamic-pituitary-adrenal (HPA)-axis to stress in adulthood. So far, it is unknown whether this HPA-axis sensitization is specific to depression, or whether this is a more general outcome associated with CA in patients with mood and anxiety disorders. The aim of this study was to investigate whether CA is associated with enhanced cortisol reactivity to psychosocial stress in Social Anxiety Disorder (SAD).

METHODS

Salivary cortisol levels before, during, and after exposure to psychosocial stress (i.e., Trier Social Stress Task, TSST) in SAD patients with a history of childhood abuse (SAD+CA, n=9) were compared to cortisol levels in SAD patients without a history of childhood abuse (SAD-CA, n=9), patients with PTSD related to childhood abuse (n=16), and healthy controls without a history of childhood abuse (n=16).

RESULTS

Analyses showed that the SAD+CA group had a strongly increased cortisol reactivity (mean peak: 17.5+/-1.9 nmol/l) compared to SAD-CA (mean peak: 9.0+/-1.1 nmol/l), PTSD (mean peak: 9.0+/-1.1 nmol/l) and healthy controls (mean peak: 9.6+/-1.4 nmol/l), whereas baseline cortisol levels did not differ. The enhanced increase in the SAD+CA group was not explained by stronger anxiety in response to the TSST.

CONCLUSIONS

Consistent with the findings in depression, these results show for the first time that childhood abuse is also associated with strongly increased cortisol reactivity in SAD. When replicated in a larger sample, these findings may have important implications for the treatment of SAD.

Neonatal overfeeding alters adult anxiety and stress responsiveness

The neonatal nutritional environment is critical for programming the systems regulating body weight, and an inappropriate nutritional environment in early life can lead to overweight or obesity later on. In this study we demonstrate that changes to the neonatal nutritional environment, induced by changing the litter size in which the animal is raised, can alter not only body weight into adulthood, but also anxiety behaviours and stress responsiveness. These effects appear to be somewhat sex-dependent, affecting female rats more strongly than males. Thus, Wistar rats raised in small litters, where they have greater access to their mothers' milk, weigh more in adulthood than those raised in large litters. Females from these small litters show enhanced exploratory behaviour and reduced anxiety in the elevated plus maze, entering the open arms more often. They also display enhanced central responses to restraint stress including greater activation of the paraventricular nucleus of the hypothalamus and paraventricular nucleus of the thalamus, possibly indicating that the changes we see are related to enhanced arousal. Thus, while neonatal litter size affects long-term body weight regulation, it can also alter long-term activity, anxiety and stress responsiveness, and the degree to which it does so appears to be sex-dependent.

Children's context inappropriate anger and salivary cortisol

Some children show emotion that is not consistent with normative appraisal of the context and can therefore be defined as context inappropriate (CI). The authors used individual growth curve modeling and hierarchical multiple regression analyses to examine whether CI anger predicts differences in hypothalamic-pituitary-adrenal axis activity, as manifest in salivary cortisol measures. About 23% of the 360 children (ages 6-10 years, primarily 7-8) showed at least 1 expression of CI anger in situations designed to elicit positive affect. Expression of anger across 2 positive assessments was less common (around 4%). CI anger predicted the hypothesized lower levels of cortisol beyond that attributed to context appropriate anger. Boys' CI anger predicted lower morning cortisol and flatter slopes. Results suggest that this novel approach to studying children's emotion across varying contexts can provide insight into affective style.

Stress selectively and lastingly promotes learning of context-related high arousing information

The secretion of adrenal stress hormones in response to acute stress is known to affect learning and memory, particularly for emotionally arousing memory material. Here, we investigated whether stress-induced modulation of learning and memory performance depends on (i) the conceptual relatedness between the material to be learned/remembered and the stressor and (ii) the timing of stress exposure versus learning phase. Participants learned stressor-related and stressor-unrelated words of varying arousal 1h prior to, immediately following, or 2h after exposure to the Trier Social Stress Test (all groups n=16). Twenty-four hours later, delayed free recall was assessed. Cortisol and alpha-amylase were sampled to evaluate if concurrent stress-induced raised glucocorticoid levels and high adrenergic activity are implicated in modulating learning performance. Our results demonstrate that immediate and delayed post-stress learning selectively enhanced the learning and delayed recall of stressor-related high arousing words. This enhancing effect was strongly associated with concurrent stress-induced cortisol and sympathetic activity. Our data suggest that when to-be-learned information is conceptually related to a stressor and considered important (i.e., arousing) by the individual, learning under stressful circumstances results in improved memorability afterwards.

Neuroendocrine and psychometric evaluation of a placebo version of the 'Trier Social Stress Test'

The "Trier Social Stress Test" (TSST) is one of the most prominent laboratory stress paradigms. It is often used to investigate the effects of stress on cognitive or affective parameters. Such studies need a non-stress control condition. However, control conditions currently employed are often rather ill defined and do not parallel important modulating variables, e.g., physical or cognitive load of the TSST. We here introduce a placebo version of the TSST, which contains a free speech and a simple mental arithmetic task without uncontrollability and social-evaluative threat. In two studies, this control condition was evaluated using salivary markers of stress reactivity (cortisol and alpha-amylase) and a questionnaire for anticipatory cognitive stress appraisal (PASA). In experiment 1 participants who were treated with the placebo condition showed no cortisol response and a small, but significant salivary alpha-amylase (sAA) response. Both responses were significantly smaller than those of TSST-treated participants. The placebo-treated participants also rated the treatment situation as less stressful. In experiment 2 a crossover study with the use of an intercom to instruct the participants and ensure their compliance was conducted. Again there was a strong cortisol response to the TSST, which differed significantly from the cortisol levels observed during the placebo condition. Importantly the cortisol response was not influenced by treatment order (TSST or placebo first). However, in this study we found similar reactions between TSST- and placebo-treated participants with regard to sAA-response. We suggest that the introduced placebo protocol for the TSST is a promising tool for future psychobiological research. The exact procedure for a given experiment should be tailored to the specific needs of the empirical question studied.

Sex-specific association between the 5-HTT gene-linked polymorphic region and basal cortisol secretion

OBJECTIVE

A key regulator of serotonergic neurotransmission is the serotonin transporter (5-HTT) and a common 5HTT gene promoter polymorphism, termed 5HTTLPR, is associated with phenotypes related to anxiety and depression. Furthermore, the serotonergic system influences hypothalamus-pituitary-adrenal (HPA) axis activity, which, in turn, is related to psychiatric diseases.

METHODS

To explore the association between the 5-HTTLPR and HPA axis regulation we performed a detailed endophenotyping in 216 healthy subjects (all 126 females used oral contraceptives).

RESULTS

While ACTH and cortisol responses to an established psychosocial stress paradigm (Trier Social Stress Test) were not found to be related to the 5-HTTLPR, we observed a significant and sex-specific association with the cortisol awakening response, which is a reliable marker of basal cortisol secretion, and with ACTH levels after dexamethasone administration. The supplementary inclusion of a 5-HTT A/G polymorphism (rs25531) in the analyses did not substantially modify our results.

CONCLUSION

These findings support the view that the 5-HTTLPR is associated with a major neuroendocrine stress system. It could be speculated that the sex-specific nature of this association contributes to the distinct gender differences in the vulnerability for depression.

Effects of steroid hormones on neurogenesis in the hippocampus of the adult female rodent during the estrous cycle, pregnancy, lactation and aging

Adult neurogenesis exists in most mammalian species, including humans, in two main areas: the subventricular zone (new cells migrate to the olfactory bulbs) and the dentate gyrus of the hippocampus. Many factors affect neurogenesis in the hippocampus and the subventricular zone, however the focus of this review will be on factors that affect hippocampal neurogenesis, particularly in females. Sex differences are often seen in levels of hippocampal neurogenesis, and these effects are due in part to differences in circulating levels of steroid hormones such as estradiol, progesterone, and corticosterone during the estrous cycle, in response to stress, with reproduction (including pregnancy and lactation), and aging. Depletion and administration of these same steroid hormones also has marked effects on hippocampal neurogenesis in the adult female, and these effects are dependent upon reproductive status and age. The present review will focus on current research investigating how hippocampal neurogenesis is altered in the adult female rodent across the lifespan.

Social comparisons and health: can having richer friends and neighbors make you sick?

Do richer friends and neighbors improve your health through positive material effects, or do they make you feel worse through the negative effect of social comparison and relative deprivation? Using the newly available National Social Life, Health, and Aging Project (NSHAP) data set that reports individuals' income positions within their self-defined social networks, this paper examines whether there is an association between relative position and health in the US. Because this study uses measures of individuals' positions within their self-defined social groups rather than researcher-imputed measures of relative position, I am able to more precisely examine linkages between individual relative position and health. I find a relationship between relative position and health status, and find indirect support for the biological mechanism underlying the relative deprivation model: lower relative position tends to be associated with those health conditions thought to be linked to physiological stress. I also find, however, that only extremes of relative position matter: very low relative position is associated with worse self-rated physical health and mobility, increased overall disease burden, and increased reporting of cardiovascular morbidity; very high relative position is associated with lower probabilities of reporting diabetes, ulcers, and hypertension. I observe few associations between health and either moderately high or moderately low positions. This analysis suggests that the mechanism underlying the relative deprivation model may only have significant effects for those at the very bottom or the very top.

Acute psychological stress reduces working memory-related activity in the dorsolateral prefrontal cortex

BACKGROUND

Acute psychological stress impairs higher-order cognitive function such as working memory (WM). Similar impairments are seen in various psychiatric disorders that are associated with higher susceptibility to stress and with prefrontal cortical dysfunctions, suggesting that acute stress may play a potential role in such dysfunctions. However, it remains unknown whether acute stress has immediate effects on WM-related prefrontal activity.

METHODS

Using functional magnetic resonance imaging (fMRI), we investigated neural activity of 27 healthy female participants during a blocked WM task (numerical N-back) while moderate psychological stress was induced by viewing strongly aversive (vs. neutral) movie material together with a self-referencing instruction. To assess stress manipulation, autonomic and endocrine, as well as subjective, measurements were acquired throughout the experiment.

RESULTS

Successfully induced acute stress resulted in significantly reduced WM-related activity in the dorsolateral prefrontal cortex (DLPFC), and was accompanied by less deactivation in brain regions that are jointly referred to as the default mode network.

CONCLUSIONS

This study demonstrates that experimentally induced acute stress in healthy volunteers results in a reduction of WM-related DLPFC activity and reallocation of neural resources away from executive function networks. These effects may be explained by supraoptimal levels of catecholamines potentially in conjunction with elevated levels of cortisol. A similar mechanism involving acute stress as a mediating factor may play an important role in higher-order cognitive deficits and hypofrontality observed in various psychiatric disorders.

Acute stress increases sex differences in risk seeking in the balloon analogue risk task

BACKGROUND

Decisions involving risk often must be made under stressful circumstances. Research on behavioral and brain differences in stress responses suggest that stress might have different effects on risk taking in males and females.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, participants played a computer game designed to measure risk taking (the Balloon Analogue Risk Task) fifteen minutes after completing a stress challenge or control task. Stress increased risk taking among men but decreased it among women.

CONCLUSIONS/SIGNIFICANCE

Acute stress amplifies sex differences in risk seeking; making women more risk avoidant and men more risk seeking. Evolutionary principles may explain these stress-induced sex differences in risk taking behavior.

Adolescents' cortisol responses to awakening and social stress; effects of gender, menstrual phase and oral contraceptives. The TRAILS study

Studies on the influence of sex hormones on cortisol responses to awakening and stress have mainly been conducted in adults, while reports on adolescents are scarce. We studied the effects of gender, menstrual cycle phase and oral contraceptive (OC) use on cortisol responses in a large sample of adolescents. Data come from TRAILS (TRacking Adolescents' Individual Lives Survey), a prospective population study of Dutch adolescents. This study uses data of 644 adolescents (age 15-17 years, 54.7% boys) who participated in a laboratory session including a performance-related social stress task (public speaking and mental arithmetic). Free cortisol levels were assessed by multiple saliva samples, both after awakening and during the laboratory session. No significant effects of gender and menstrual phase on cortisol responses to awakening were found, while girls using OC displayed a slightly blunted response (F(1, 244)=5.30, p=.02). Cortisol responses to social stress were different for boys and free-cycling girls (F(3, 494)=9.73, p<.001), and OC users and free-cycling girls (F(3, 279)=15.12, p<.001). Unexpectedly, OC users showed no response at all but displayed linearly decreasing levels F(1, 279)=19.03, p<.001) of cortisol during the social stress test. We found no effect of menstrual cycle phase on cortisol responses to social stress (F(3, 157)=0.58, p=.55). The absence of a gender difference in the adolescents' cortisol awakening response found in this study is consistent with previous reports. Our results further suggest that adolescent OC users display slightly blunted cortisol responses after awakening, and that gender differences in cortisol responses to social stress during adolescence are comparable to those described for adult populations, that is, stronger responses in men than in women. Whereas previous work in adults suggested blunted stress responses in OC users compared to men and free-cycling women, adolescent OC users showed no cortisol response. Effects of type of OC could not be studied because of low numbers of OC that were only progestin based.

Sex and gender in psychoneuroimmunology research: past, present and future

To date, research suggests that sex and gender impact pathways central to the foci of psychoneuroimmunology (PNI). This review provides a historical perspective on the evolution of sex and gender in psychoneuroimmunology research. Gender and sexually dimorphic pathways may have synergistic effects on health differences in men and women. We provide an overview of the literature of sex and gender differences in brain structure and function, sex steroids, gender role identification, hypothalamic-pituitary-adrenal axis function, genetics, immunology and cytokine response. Specific examples shed light on the importance of attending to sex and gender methodology in PNI research and recommendations are provided.

Salivary cortisol among American Indians with and without posttraumatic stress disorder (PTSD): gender and alcohol influences

Disruptions in hypothalamic-pituitary-adrenal regulation and immunity have been associated with posttraumatic stress disorder (PTSD). We examined the association of PTSD with diurnal rhythms in salivary cortisol in a convenience sample from a population-based study of male and female American Indians. Subjects with and without PTSD were identified from American Indians living on/near a Northern Plains reservation as part of a larger study. Over two days diurnal saliva samples were collected by staff at the University of Colorado Denver Clinical Research Center at waking, 30min after waking, before lunch, and before dinner. Generalized estimating equations linear regression models investigated the influence of PTSD on cortisol over time. The association of a lifetime diagnosis of PTSD with salivary cortisol level was assessed in subjects with complete data (PTSD: n=27; no PTSD n=32) for age, gender, and alcohol consumption in the past month. Subject mean age was 44 years, and 71% were women. When stratified by gender, women with a lifetime diagnosis of PTSD had significantly higher mean cortisol levels throughout the day than women without PTSD (p=0.01); but there was no significant association between PTSD and cortisol levels in men (p=0.36). The cortisol awakening response - the difference in cortisol levels from waking to 30min after waking - was not associated with PTSD in men or women. A lifetime diagnosis of PTSD may influence diurnal cortisol among American Indian women. These effects were independent of influences of current alcohol use/abuse. The unexpected elevation in cortisol in American Indian women with a lifetime diagnosis of PTSD may reflect acute anxiety associated with experiencing a number of novel tests in a strange location (e.g., cardiac imaging, medical, dental exams, etc.), or concurrent depression.

Hippocampal damage abolishes the cortisol response to psychosocial stress in humans

The hippocampus (HC) is necessary for learning and memory, but it also plays a role in other behaviors such as those related to stress and anxiety. In support of the latter idea, we show here that bilateral HC damage abolishes the cortisol response to psychosocial stress. We collected salivary cortisol, heart rate, and affective responses to the Trier Social Stress Test (TSST) from 7 participants with bilateral HC lesions, 12 participants with damage outside the HC, and 28 healthy normal comparison participants matched to the HC participants on age and sex. HC participants showed elevated pre-stress cortisol, but no cortisol response to the TSST. Heart rate and affective responses in the HC group were similar to those of the comparison groups. Participants with brain damage outside the HC showed stress responses that were comparable to those of the healthy comparison group. These findings support the idea that the functions of the human HC extend beyond learning and memory, and suggest that the HC is necessary for producing the cortisol response to psychosocial stress.

Structure provided by parents in middle childhood predicts cortisol reactivity in adolescence among the offspring of parents with bipolar disorder and controls

Recent studies suggest that childhood exposure to adversity influences later functioning of the hypothalamic-pituitary-adrenal (HPA) axis. Parenting style in childhood, a putative moderator of adversity, may be important in determining HPA reactivity in adolescence. As part of a prospective, longitudinal study, saliva was collected at awakening and 30 and 60 min later over 2 days among 27 offspring of parents with bipolar disorder (high risk; 16.7+/-1.5 years) and 26 offspring of parents with no mental disorders (low risk; 16.2+/-1.7 years). In addition, 24 of the high risk and 22 of the low risk adolescents completed the "Trier Social Stress Test" (TSST). Parents had rated their parenting style when their offspring were 6-13 years of age. Low levels of structure (i.e. organization and consistency) provided by parents in middle childhood were predictive of an elevated cortisol response following awakening (beta=-0.36; p<0.05) and during the TSST (beta=-0.33; p<0.05), even while controlling for risk group. These associations were independent of other indices of environmental risk, and of adolescents' mood and behavior. The level of structure provided by parents in childhood predicted independent measures of cortisol reactivity in adolescence, suggesting that parenting style may regulate different aspects of HPA reactivity.

Plasma omega-3 and psychological distress among Nunavik Inuit (Canada)

Marine omega-3 (n-3) fatty acid eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids have been associated with beneficial effects in mental health. Cultural and social changes have been related to a decline in mental health of the Inuit, but the role of diet has received scant attention. We examined the relationship between psychological distress (PD) and plasma n-3 among 368 Nunavik Inuit aged 18-74 years who took part in a survey in 1992. Participants were categorized as high-level PD if they scored over the 80th percentile of the PD Index Santé-Québec Survey (PDISQS-14), and non-distressed subjects were those who scored less than this cutoff. Compared with the non-distressed group, n-3 concentrations in the PD group were significantly lower in women but not in men. Compared with the lowest tertile of EPA + DHA, the odds ratios for high-level PD among women were 0.32 (95% CI: 0.13-0.82) for the second, and 0.30 (95% CI: 0.10-0.90) for the third tertile, after controlling for confounders. In males, there were no significant associations between EPA+DHA and PDISQS-14 scores. Our findings suggest that marine n-3 may play a role in PD among Inuit women. The gender difference observed in our analysis must be examined more carefully in future studies.

Response to corticotropin-releasing hormone infusion in cocaine-dependent individuals

CONTEXT

Corticotropin-releasing hormone (CRH), through the hypothalamic pituitary adrenal axis and other brain stress systems, is involved in the emotional dysregulation associated with cocaine dependence. Little is known about the response of cocaine-dependent individuals to CRH administration.

OBJECTIVE

The primary objective was to examine the hypothalamic-pituitary-adrenal axis and the subjective and physiologic response to CRH in cocaine-dependent individuals and controls.

DESIGN

A case-control study.

SETTING

Subjects were admitted to a General Clinical Research Center for testing and abstinence was verified with a urine drug screening.

PARTICIPANTS

Participants were male controls (n = 23), female controls (n = 24), cocaine-dependent men (n = 28), and cocaine-dependent women (n = 25). Individuals with dependence on other substances (except caffeine or nicotine) or with major depression, posttraumatic stress disorder, bipolar disorder, or psychotic or eating disorders were excluded.

INTERVENTION

Subjects received 1 microg/kg of CRH intravenously.

MAIN OUTCOME MEASURES

Primary outcomes included plasma corticotropin levels, cortisol levels, and heart rate and subjective measurements.

RESULTS

Cocaine-dependent individuals exhibited higher stress (P < .001) and craving for CRH compared with controls. A positive correlation (r(s) = 0.51; P < .001) between stress and craving was found in cocaine-dependent subjects. Intravenous CRH elevated heart rates in all groups; however, cocaine-dependent women demonstrated a significantly higher heart rate at all time points (P = .05). Women had higher cortisol responses to CRH (P = .03). No effect of cocaine status was observed. The corticotropin response to CRH was independent of sex and cocaine dependence. Cortisol and corticotropin were positively correlated in the controls and cocaine-dependent men, but not in cocaine-dependent women (r(s) = 0.199; P = .4).

CONCLUSIONS

There is an increased subjective and heart rate response to CRH and a relationship between stress and craving in cocaine-dependent individuals. The lack of difference in hypothalamic pituitary adrenal axis response between the cocaine-dependent and control groups suggests that the heart rate and subjective responses in the cocaine group may be mediated by sensitization of nonhypothalamic stress-responsive CRH systems.

Subjective Sleep Quality and hormonal modulation in long-term yoga practitioners

Yoga represents a fascinating mind-body approach, wherein body movements (asana), breathing exercises (pranayama) and meditation are integrated into a single multidimensional practice. Numerous beneficial mental and physical effects have been classically ascribed to this holistic ancient method. The purpose of the present study has been to examine the effects of long-term yoga practice on Subjective Sleep Quality (SSQ) and on several hormonal parameters of the hypothalamus-pituitary-adrenal (HPA) axis. Twenty-six subjects (16 experimental and 10 controls) were recruited to be part of the study. Experimental subjects were regular yoga practitioners with a minimum of 3 years of practice. Blood samples for the quantification of adrenocorticotropic hormone (ACTH), cortisol and dehydroepiandrosterone sulphate (DHEA-S) were drawn from all subjects. Likewise, the Pittsburgh Sleep Quality Index (PSQI) was employed to assess SSQ. As statistical analysis, Mann-Whitney U-test was performed. The yoga group displayed lower PSQI scores and higher blood cortisol levels than control subjects. Therefore, it can be concluded that long-term yoga practice is associated with significant psycho-biological differences, including better sleep quality as well as a modulatory action on the levels of cortisol. These preliminary results suggest interesting clinical implications which should be further researched.

Stress effects on declarative memory retrieval are blocked by a beta-adrenoceptor antagonist in humans

Previous evidence indicates that stress hormone effects on memory consolidation depend on concurrent emotional arousal-induced noradrenergic activity. Here, we asked whether this is also true for stress effects on memory retrieval and hypothesized that administration of the beta-adrenoceptor antagonist propranolol would block the effects of stress on declarative and procedural retrieval performance. In a double-blind, placebo-controlled, crossover study, 44 healthy young men learned a list of emotional and neutral words (declarative memory task) and completed a serial reaction time task (procedural memory task). On the following day, participants received either a placebo or 40 mg propranolol orally. One hour later, they were exposed to stress (socially evaluated cold pressor test (SECPT)) or a control condition 30 min prior to retention testing. Stress selectively enhanced the retrieval of emotionally arousing words. Pretreatment with propranolol had no effect on memory alone but blocked the stress-induced memory enhancement for emotional words, confirming the importance of noradrenergic activity in stress effects on memory retrieval. Memory for neutral words and the procedural task was neither affected by stress nor by propranolol. The present findings suggest that stress (hormone) effects on emotional memory retrieval require concurrent noradrenergic activation. Procedural memory retrieval and the retrieval of neutral verbal material appear to be less susceptible to stress.

BDNF Val66Met polymorphism is associated with HPA axis reactivity to psychological stress characterized by genotype and gender interactions

BACKGROUND

A key protein in maintaining neuronal integrity throughout the life span is brain-derived neurotrophic factor (BDNF). The BDNF gene is characterized by a functional polymorphism, which has been associated with stress-related disorders such as anxiety-related syndromes and depression, prompting us to examine individual responses by Genotype and Sex to a standardized social stress paradigm. Gender differences in BDNFxstress responses were posited because estrogen induces synthesis of BDNF in several brain regions.

METHODS

97 university students (51 females and 46 males) participated in a social stress procedure (Trier Social Stress Test, TSST). Indices of stress were derived from repeated measurement of cortisol, blood pressure, and heart rate during the TSST. All subjects were genotyped for the Val66Met polymorphism.

RESULTS

Tests of within-subject effects showed a significant three-way interaction (SPSS GLM repeated measures: Time (eight levels)xBDNF (val/val, val/met)xSex: p=0.0002), which reflects gender differences in the pattern of cortisol rise and decline during the social challenge. In male subjects, val/val homozygotes showed a greater rise in salivary cortisol than val/met heterozygotes. In female subjects, there was a trend for the opposite response, which is significant when area under the curve increase (AUCi) was calculated for the val/val homozygotes to show the lowest rise. Overall, the same pattern of results was observed for blood pressure and heart rate.

CONCLUSIONS

These results indicate that a common, functionally significant polymorphism in the BDNF gene modulates HPA axis reactivity and regulation during the TSST differently in men and women. Findings may be related to gender differences in reactivity and vulnerability to social stress.

Sex differences in corticolimbic dopamine and serotonin systems in the rat and the effect of postnatal handling

Stress-related psychopathology is particularly prevalent in women, although the neurobiological reason(s) for this are unclear. Dopamine (DA) and serotonin (5-HT) systems however, are known to play important adaptive roles in stress and emotion regulation. The aims of the present study included examination of sex differences in stress-related behaviour and neuroendocrine function as well as post mortem neurochemistry, with the main hypothesis that corticolimbic DA and 5-HT systems would show greater functional activity in males than females. Long-Evans rats of both sexes were employed. Additional factors incorporated included differential postnatal experience (handled vs. nonhandled) and adult mild stress experience (acute vs. repeated (5) restraint). Regional neurochemistry measures were conducted separately for left and right hemispheres. Behaviourally, females showed more exploratory behaviour than males in the elevated plus maze and an openfield/holeboard apparatus. Females also exhibited significantly higher levels of adrenocorticotrophic hormone and corticosterone at all time points in response to restraint stress than males across treatment conditions, although both sexes showed similar habituation in stress-induced ACTH activation with repeated mild stress. Neurochemically, females had significantly higher levels of DA (in ventromedial prefrontal cortex (vmPFC), insular cortex and n. accumbens) and 5-HT (in vmPFC, amygdala, dorsal hippocampus and insula) than males. In contrast, males had higher levels of the DA metabolite DOPAC or DOPAC/DA ratios than females in all five regions and higher levels of the 5-HT metabolite 5-HIAA or 5-HIAA/5-HT ratios in vmPFC, amygdala and insula, suggesting greater neurotransmitter utilization in males. Moreover, handling treatment induced a significant male-specific upregulation of 5-HT metabolism in all regions except n. accumbens. Given the adaptive role of 5-HT and DAergic neurotransmission in stress and emotion regulation, the intrinsic sex differences we report in the functional status of these systems across conditions, may be highly relevant to the differential vulnerability to disorders of stress and emotion regulation.

Hypothalamic-pituitary-adrenal axis function: relative contributions of perceived stress and obesity in women

OBJECTIVE

A range of behavioral and psychosocial factors may contribute to a chronically stimulated hypothalamic-pituitary-adrenal (HPA) axis and subsequently altered diurnal patterns. The goal of this cross-sectional study was to examine associations among diurnal cortisol levels, perceived stress, and obesity patterns.

METHODS

Seventy-eight women (aged 24-72 years) employed in a rural public school system completed the perceived stress scale, collected diurnal saliva samples, and underwent anthropometric assessments. Reduced peak-to-nadir cortisol values across the day were considered a sign of impairment in HPA function. A series of linear regression models determined the best predictors of diurnal cortisol variation.

RESULTS

There was a marginal linear trend in stress levels across body mass index (BMI) categories, with obese women reporting the highest levels of stress (p = 0.07). Perceived stress was the only significant predictor of the degree of flattening of the diurnal cortisol curve in the sample as a whole (beta = -0.042, R(2) = 0.11, F = 8.6, p = 0.005), indicating reduction in the normal diurnal pattern. Among overweight women (BMI = 25-29.9 kg/m(2)), stress and waist circumference combined predicted 35% of the variability in diurnal cortisol. In contrast, among obese women (BMI > or = 30 kg/m(2)), BMI predicted 31% of the variability in diurnal cortisol (F = 13.8, p = 0.001), but stress was no longer significantly related to diurnal cortisol.

CONCLUSIONS

Psychological stress predicts a significant portion of HPA axis functioning. In overweight women, perceived stress and waist circumference were of approximately equal importance in predicting adrenal cortisol secretion. However, among obese women, a major portion of the diurnal cortisol variation was predicted by BMI alone, not stress or waist circumference. This may help elucidate the mechanisms linking obesity to increased risk of cardiovascular disease (CVD).

Salivary cortisol and psychosocial hazards at work

BACKGROUND

Experimental and clinical evidence suggest that stress can lead to ill-health through the disregulation of the hypothalamic-pituitary-adrenal (HPA) axis. Studies to date have produced equivocal results likely due to different methodologies and failure to account for confounding factors. This investigation aimed to assess the relation between self-reported work-related stressors and salivary cortisol and to clarify the role of the potential confounders.

METHODS

Thirty-six call-handlers completed a self-administered job content questionnaire and collected seven daily salivary samples on two workdays and a weekend. The diurnal salivary cortisol output was expressed as cortisol awakening response (CAR), and cortisol output in the rest of the day. Salivary cortisol data were normalized by means of square root transformation. The generalized estimating equations method was used to assess the relation between job strain and cortisol levels after adjusting for gender, weekdays and adherence to the sampling schedule.

RESULTS

Job strain significantly influenced the total amount of cortisol response to waking (high strain vs. low strain: 1.1 (0.3-2.0) nmol/L). The cortisol response to waking showed gender-specific differences [women excreting greater cortisol than men: 1.1 (0.3-1.9) nmol/L], and weekday differences [workdays vs. weekend: 1.0 (0.3-1.6) nmol/L]. Non-compliance with the sampling protocol was associated with lower salivary cortisol than in adherent subjects.

CONCLUSIONS

Our results provide further evidence for the HPA axis involvement in the physiological response to work stress. The measure of the CAR showed to be the sensitive index to assess the physiological response to psychosocial factors. Gender, weekday, and protocol compliance were confounding factors.

Chronic social instability stress in female rats: a potential animal model for female depression

Epidemiological studies demonstrate that affective disorders are at least twice as common in women as in men, but surprisingly, very few preclinical studies have been conducted on female experimental animals. Therefore, the necessity of developing valid animal models for studying the pathophysiology of stress-related disorders in women is obvious. Chronic social stress has the potential to induce depression in humans and therefore we characterize here a chronic social instability stress paradigm in female rats. This consists of a 4-week period with alternating stressful social situations, including phases of isolation and crowding, in an unpredictable manner. At the physiological level, increased adrenal weight and plasma corticosterone levels indicated hyperactivity of the hypothalamus-pituitary-adrenal axis. Elevated plasma luteinizing hormone and disruption of the estrus cycle together with increased serum prolactin levels revealed disrupted regulation of the hypothalamus-pituitary-gonadal axis. Body temperature regulation was affected during the last week of stress such that stressed rats reduced their body temperature less during the rest phase than the controls, thus exhibiting a flattened temperature curve. Behaviorally, chronically stressed rats showed reduced sucrose preference and food intake. However, we did not observe any effect of stress on performance in the forced swim test and hippocampal neurotrophin levels were similarly unaffected. Our results indicate that, by using this social instability paradigm, female rats can be kept under chronic stress for weeks without habituation, and that ultimately the animals develop a depressive-like phenotype. This model may provide a valuable tool for further analyses of the neurobiology of stress-related disorders in women and has the potential to serve as a paradigm for screening novel antidepressant drugs with special efficacy in women.

Suppressive effect of mirtazapine on the HPA system in acutely depressed women seems to be transient and not related to antidepressant action

Impaired regulation of the hypothalamus-pituitary-adrenocortical (HPA) system is a consistent finding among patients with depression, which can be most sensitively detected with the combined dexamethasone (dex)/corticotrophin releasing hormone (CRH) test. The majority of patients with acute depression shows an exaggerated plasma corticotrophin (ACTH) and cortisol response to this test that normalizes gradually during successful antidepressant therapy. In contrast, persistently high HPA-responses to this challenge are prognostically less favorable. It has been recently questioned, whether this observation applies also to treatment with the atypical antidepressant mirtazapine, as patients treated with this drug showed a distinct attenuation of the endocrine response to the dex/CRH test already after 1 week of treatment. In the present study, we investigated whether the attenuating effect of mirtazapine on the HPA system is an acute pharmacological reaction disappearing after physiological adaptation or whether this effect is related to the antidepressant action of the drug. We examined plasma ACTH and cortisol responses to the dex/CRH test in acutely depressed inpatients treated either with mirtazapine (n=55) or a monoamine reuptake inhibitor (n=105) according to doctor's choice and compared the test results with healthy controls (n=40). Patients treated with monoamine reuptake inhibitors received either selective serotonin reuptake inhibitors (SSRI), tricyclic antidepressants (TCA) or the combined serotonin and noradrenalin reuptake inhibitor venlafaxine. We found increased plasma ACTH and cortisol responses to the dex/CRH test in depressed patients compared with healthy controls, but also significantly (p=.017) attenuated plasma cortisol secretion in the mirtazapine group compared to the group of monoamine reuptake inhibitor treated patients. This effect was not significant in male patients. Furthermore this effect was independent of the psychopathological state, but depended on treatment duration. Patient treatment with mirtazapine for up to 7 days resulted in dex/CRH test outcome that was indistinguishable from controls. This effect, however waned as it was not observable in patients treated for a longer period. These results suggest that short-term administration of mirtazapine has immediate but only transient suppressive effects on the HPA system predominantly in women. Our results confirm that dex/CRH tests can be used as predictors of clinical course also under mirtazapine treatment.

The ultradian and circadian rhythms of free corticosterone in the brain are not affected by gender: an in vivo microdialysis study in Wistar rats

Recently, we described that free corticosterone levels in the brain of male Wistar rats, as assessed by in vivo microdialysis, show an ultradian rhythm with a pulse frequency of 1.2 pulses/h. To establish whether gender influences brain free corticosterone rhythms, we studied free corticosterone levels in the female Wistar rat under baseline and stressful conditions using microdialysis in the hippocampus. Analysis of the data with the PULSAR algorithm revealed that hippocampal free corticosterone levels show a clear ultradian pattern in female rats with a pulse frequency of 1.16+/-0.05 pulses/h between 09.00 h and 21.00 h. Further analysis showed that the pulse amplitude is significantly higher during the late afternoon/early night (15.00-21.00 h) than during the morning/early afternoon (09.00-15.00 h) phase (0.13+/-0.03 versus 0.07+/-0.01 microg/dl, respectively, P < 0.05). Pulse characteristics were extremely reproducible as demonstrated by the almost identical pulse parameters derived from two consecutive 24-h periods [pulse frequency: 1.13+/-0.09 and 1.19+/-0.08 pulses/h; pulse amplitude: 0.11+/-0.05 and 0.10+/-0.02 microg/dl for day 1 and day 2 (09.00-21.00 h) respectively, P > 0.05]. Both exposure to a novel environment and forced swim stress increased hippocampal free corticosterone levels. However, the stress-induced rise reached higher levels and was more prolonged after forced swimming (area under the curve: 46.84+/-9.25 and 12.08+/-1.69 arbitrary units for forced swimming and novelty stress respectively, P = 0.01). Importantly, the ultradian rhythm was rapidly restored after termination of the stress response. This is the first demonstration that the female rat brain is exposed to free corticosterone levels that follow a circadian as well as an ultradian pattern and show almost identical pulse characteristics as recently reported in male animals. These observations are of significance for further investigations into the dynamics of glucocorticoid action in the brain of both genders.

Estrogen impairs glucocorticoid dependent negative feedback on the hypothalamic-pituitary-adrenal axis via estrogen receptor alpha within the hypothalamus

Numerous studies have established a link between individuals with affective disorders and a dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, most notably characterized by a reduced sensitivity to glucocorticoid negative (-) feedback. Furthermore there is a sex difference in the etiology of mood disorders with incidence in females being two to three times that of males, an association that may be a result of the influence of estradiol (E2) on HPA axis function. In these studies, we have examined the effect of E2 on glucocorticoid-mediated HPA axis (-) feedback during both the diurnal peak and the stress-induced rise in corticosterone (CORT). Young adult female Sprague-Dawley (SD) rats were ovariectomized (OVX) and 1 week later treated subcutaneous (s.c.) with oil or estradiol benzoate (EB) for 4 days. On the 4th day of treatment, animals were injected with a single dose of dexamethasone (DEX), or vehicle. EB treatment significantly increased the evening elevation in CORT and the stress-induced rise in CORT. In contrast, DEX treatment reduced the diurnal and stress induced rise in CORT and adrenocorticotropic hormone (ACTH), and this reduction was not apparent following co-treatment with EB. To determine a potential site of E2's action, female SD rats were OVX and 1 week later, wax pellets containing E2, the estrogen receptor beta (ERbeta) agonist diarylpropionitrile (DPN), or the estrogen receptor alpha (ERalpha) agonist propylpyrazoletriol (PPT), was implanted bilaterally and dorsal to the paraventricular nucleus of the hypothalamus (PVN). Seven days later, animals were injected s.c. with a single dose of DEX, or vehicle to test for glucocorticoid-dependent (-) feedback. Results show that E2 and PPT increased, while DPN decreased the diurnal peak and stress-induced CORT and ACTH levels as compared to controls. Furthermore, E2 and PPT impaired the ability of DEX to inhibit both the diurnal and the stress-induced rise in CORT and ACTH, whereas DPN had no effect. Neuronal activation was measured by c-fos mRNA expression within the PVN following restraint. E2 and PPT increased c-fos mRNA, and impaired the normal DEX suppression of neuronal activation in the PVN. Taken together, these data indicate that estradiol causes a dysregulation of HPA axis (-) feedback as evidenced by the inability of DEX to suppress diurnal and stress-induced CORT and ACTH secretion. Additionally, the ability of E2 to inhibit glucocorticoid (-) feedback occurs specifically via ERalpha acting at the level of the PVN.

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.

Stress impairs acquisition of delay eyeblink conditioning in men and women

In rodents stress impairs delay as well as trace eyelid conditioning in females, but enhances it in males. The present study tested the effects of acute psychosocial stress exposure on classical delay eyeblink conditioning in healthy men and women. In a between subject design, participants were exposed to psychosocial stress using the Trier Social Stress Test (TSST) or a control condition which was followed by a delay eyeblink classical conditioning procedure. Stress exposure led to a significant increase in salivary cortisol and impaired acquisition of conditioned eyeblink responses (CRs). This was evident by a later first CR and an overall lower CR rate of the stress group. The stress-induced acquisition impairment was observed in both women and men. Subjects failing to show a stress-induced cortisol increase (cortisol non-responder) were not impaired in acquisition. Our findings indicate that acute stress, possibly via activation of the hypothalamus-pituitary-adrenal (HPA) axis, reduces the ability to acquire a simple conditioned motor response in humans.