Corticotropin releasing hormone stimulation test and nocturnal cortisol levels in normal children

The Association of the Hypothalamic-Pituitary-Adrenal Axis with Appetite Regulation in Children with Fetal Alcohol Spectrum Disorders (FASDs)

Prenatal alcohol exposure causes growth impairment and a wide range of developmental, physical, and cognitive disorders in children, collectively referred to as fetal alcohol spectrum disorders (FASDs). In the course of FASDs, abnormalities can also affect eating behavior and nutritional status, but these problems have received little attention. Therefore, the aim of our study was to determine the levels of hormones involved in the action of the hypothalamic–pituitary–adrenal axis: proopiomelanocortin (POMC), cortisol, and adrenocorticotropic hormone (ACTH), in the serum of patients with FASDs. To our knowledge, none of these hormones studied have yet been evaluated in FASDs to date. We investigated 62 FASD patients and 23 healthy controls by applying an enzyme-linked immunosorbent method (ELISA). Fasting POMC levels were significantly lower in patients with FASDs (10.97 vs. 18,57 ng/mL, p = 0.039) compared to controls. However, there were no differences in cortisol concentrations. Additionally, the sex and subgroup status (fetal alcohol syndrome (FAS), neurobehavioral disorder associated with prenatal alcohol exposure (ND-PAE), and FASD risk) did not affect hormone levels. POMC was positively correlated with some clinical parameters such as age, BMI percentile, carbohydrate biomarkers, and ACTH. A positive correlation was observed between ACTH and cortisol levels, as well as ACTH and cholesterol levels. Data analysis showed no HPA axis abnormalities in the form of elevated serum cortisol and ACTH levels. Differences in POMC concentration may indicate the involvement and/or impairment of central nervous system structures in hormonal alterations in FASD individuals, caused by prenatal alcohol exposure. Hormonal dysregulation in FASDs can contribute to reduced growth and development, as well as many other disturbed processes, including neurological/neurodevelopmental dysfunctions. Further insightful studies involving a larger group of patients are needed to determine the potential impact of the measured hormones.

Sex Differences in Depression Caused by Early Life Stress and Related Mechanisms

Depression is a common psychiatric disease caused by various factors, manifesting with continuous low spirits, with its precise mechanism being unclear. Early life stress (ELS) is receiving more attention as a possible cause of depression. Many studies focused on the mechanisms underlying how ELS leads to changes in sex hormones, neurotransmitters, hypothalamic pituitary adrenocortical (HPA) axis function, and epigenetics. The adverse effects of ELS on adulthood are mainly dependent on the time window when stress occurs, sex and the developmental stage when evaluating the impacts. Therefore, with regard to the exact sex differences of adult depression, we found that ELS could lead to sex-differentiated depression through multiple mechanisms, including 5-HT, sex hormone, HPA axis, and epigenetics.

Masculinized Second-to-Fourth Digit Ratio (2D:4D Ratio) Is Associated With Lower Cortisol Response in Infant Female Rhesus Monkeys (Macaca mulatta)

The second-to-fourth digit ratio (2D:4D ratio) is considered a postnatal proxy measure for the degree of prenatal androgen exposure (PAE), which is the primary factor responsible for masculinizing the brain of a developing fetus. Some studies suggest that the organizational effects of PAE may extend to the hypothalamic-pituitary-adrenal (HPA) axis response to stress. This study investigates the relationship between 2D:4D ratio and HPA axis functioning using a rhesus monkey (Macaca mulatta) model. Subjects were N = 268 (180 females, 88 males) rhesus monkey infants (3–4 months of age). Plasma cortisol concentrations were assayed from two blood samples obtained during a 25-h experimental social separation stressor at 2- and 7-h post-separation. Subjects’ 2D:4D ratio was measured later in life (M_age = 6.70 years). It was hypothesized that infant rhesus monkeys that exhibited a more masculine-like 2D:4D ratio would show lower levels of circulating cortisol after a social separation and relocation stressor. The results showed that there was a sex difference in the left-hand 2D:4D ratio. The results also showed that there was an overall sex difference in cortisol concentrations and that female, but not male, monkeys that exhibited a more masculine-like right- and left-hand 2D:4D ratio exhibited lower mean stress-induced cortisol concentrations early in life. These findings suggest that higher levels of prenatal androgens in females, as measured by 2D:4D ratio, may be related to an attenuated HPA axis stress-response, as measured by plasma cortisol levels. To the extent that these findings generalize to humans, they suggest that the organizational effects of PAE extend to the infant HPA axis, modulating the HPA axis response, particularly in females.

Childhood adversity and mechanistic links to hypertension risk in adulthood

Adverse childhood experiences (ACEs), defined as traumatic events in childhood that range from various forms of abuse to household challenges and dysfunction, have devastating consequences on adult health. Epidemiological studies in humans and animal models of early life stress (ELS) have revealed a strong association and insight into the mechanistic link between ACEs and increased risk of cardiovascular disease (CVD). This review focuses on the mechanistic links of ACEs in humans and ELS in mice and rats to vasoactive factors and immune mediators associated with CVD and hypertension risk, as well as sex differences in these phenomena. Major topics of discussion in this review are as follows: (a) epidemiological associations between ACEs and CVD risk focusing on hypertension, (b) evidence for association of ACE exposures to immune-mediated and/or vasoactive pathways, (c) rodent models of ELS-induced hypertension risk, (d) proinflammatory mediators and vasoactive factors as mechanisms of ELS-induced hypertension risk. We also provide some overall conclusions and directions of further research. LINKED ARTICLES: This article is part of a themed section on Immune Targets in Hypertension. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.12/issuetoc.

A Japanese patient with congenital central hypothyroidism caused by a novel IGSF1 mutation

BACKGROUND

IGSF1 abnormality causes diverse symptoms, including congenital central hypothyroidism (CCH), prolactin hyposecretion, testicular enlargement and delayed puberty.

CASE PRESENTATION

Here, we report a case of a male patient who visited our hospital with a chief complaint of abdominal pain and short stature, in whom we identified a novel IGSF1 mutation. He was closely examined because of chronic constipation since infancy, persistent abdominal pain at 14 years of age and marked short stature (-4.7 standard deviation [SD] for normal Japanese boys). He was diagnosed with CCH. Decreased prolactin (PRL) secretion was also observed. IGSF1 analysis revealed a novel mutation at the splicing donor site (c.2065+1G>A) in intron 11. In silico analysis predicted this mutation to be a non-functional splice donor site. After thyroid hormone replacement, his thyroid function, constipation and growth rate improved.

CONCLUSIONS

This is the first report of a patient in whom constipation and short stature led to a diagnosis of CCH with a novel IGSF1 mutation.

Is HPA axis reactivity in childhood gender-specific? A systematic review

BACKGROUND

In adults, hypothalamus-pituitary-adrenal (HPA) axis activity shows sexual dimorphism, and this is thought to be a mechanism underlying sex-specific disease incidence. Evidence is scarce on whether these sex differences are also present in childhood. In a meta-analysis, we recently found that basal (non-stimulated) cortisol in saliva and free cortisol in 24-h urine follow sex-specific patterns. We explored whether these findings could be extended with sex differences in HPA axis reactivity.

METHODS

From inception to January 2016, PubMed and EMBASE.com were searched for studies that assessed HPA axis reactivity in healthy girls and boys aged ≤18 years. Articles were systematically assessed and reported in the categories: (1) diurnal rhythm, (2) cortisol awakening response (CAR), (3) protocolled social stress tests similar or equal to the Trier Social Stress Test for children (TSST-C), (4) pharmacological (ACTH and CRH) stress tests, and (5) miscellaneous stress tests.

RESULTS

Two independent assessors selected 109 out of 6158 records for full-text screening, of which 81 studies (with a total of 14,591 subjects) were included. Studies showed that girls had a tendency towards a more variable diurnal rhythm (12 out of 29 studies), a higher CAR (8 out of 18 studies), and a stronger cortisol response to social stress tests (9 out of 21 studies). We found no evidence for sex differences in cortisol response after a pharmacological challenge or to miscellaneous stress tests.

DISCUSSION

Sex differences in HPA axis reactivity appear to be present in childhood, although evidence is not unequivocal. For a better evaluation of sex differences in HPA axis reactivity, standardization of protocols and reports of stress tests is warranted.

Peak cortisol response to corticotropin-releasing hormone is associated with age and body size in children referred for clinical testing: a retrospective review

Background

Corticotropin-Releasing Hormone (CRH) testing is used to evaluate suspected adrenocorticotropic hormone (ACTH) deficiency, but the clinical characteristics that affect response in young children are incompletely understood. Our objective was to determine the effect of age and body size on cortisol response to CRH in children at risk for ACTH deficiency referred for clinical testing.

Methods

Retrospective, observational study of 297 children, ages 30 days – 18 years, undergoing initial, clinically indicated outpatient CRH stimulation testing at a tertiary referral center. All subjects received 1mcg/kg corticorelin per institutional protocol. Serial, timed ACTH and cortisol measurements were obtained. Patient demographic and clinical factors were abstracted from the medical record. Patients without full recorded anthropometric data, pubertal assessment, ACTH measurements, or clear indication for testing were excluded (number remaining = 222). Outcomes of interest were maximum cortisol after stimulation (peak) and cortisol rise from baseline (delta). Bivariable and multivariable linear regression analyses were used to assess the effects of age and size (weight, height, body mass index (BMI), body surface area (BSA), BMI z-score, and height z-score) on cortisol response while accounting for clinical covariates including sex, race/ethnicity, pubertal status, indication for testing, and time of testing.

Results

Subjects were 27 % female, with mean age of 8.9 years (SD 4.5); 75 % were pre-pubertal. Mean peak cortisol was 609.2 nmol/L (SD 213.0); mean delta cortisol was 404.2 nmol/L (SD 200.2). In separate multivariable models, weight, height, BSA and height z-score each remained independently negatively associated (p < 0.05) with peak and delta cortisol, controlling for indication of testing, baseline cortisol, and peak or delta ACTH, respectively. Age was negatively associated with peak but not delta cortisol in multivariable analysis.

Conclusions

Despite the use of a weight-based dosing protocol, both peak and delta cortisol response to CRH are negatively associated with several measures of body size in children referred for clinical testing, raising the question of whether alternate CRH dosing strategies or age- or size-based thresholds for adequate cortisol response should be considered in pediatric patients, or, alternatively, whether this finding reflects practice patterns followed when referring children for clinical testing.

Electronic supplementary material

The online version of this article (doi:10.1186/s13633-015-0018-y) contains supplementary material, which is available to authorized users.

Neonatal hydrocortisone therapy does not have a serious suppressive effect on the later function of the hypothalamus-pituitary-adrenal axis

AIM

This study investigated whether providing extremely low birthweight (ELBW) infants with a large amount of hydrocortisone had a serious suppressive effect on the later function of the hypothalamus-pituitary-adrenal (HPA) axis.

METHODS

We evaluated the function of the HPA axis in 58 ELBW infants receiving 9.0 ± 7.2 mg/kg of intravenous and 68.1 ± 34.1 mg/kg of oral hydrocortisone using a human corticotropin-releasing hormone stimulation test. The mean age at investigation was 12.0 ± 5.2 months. The response was judged to be normal when the maximum to minimum ratio of the plasma adrenocorticotropic hormone (ACTH) concentration was >2, the peak value of the serum cortisol concentration was >552 nmol/L, or the increment was >193 nmol/L than baseline concentration.

RESULTS

Of the 58 infants studied, 51 (88%) displayed a normal response to both the ACTH and cortisol secretion and seven infants (12%) who were judged to be poor responders exhibited a peak cortisol value of >386 nmol/L without any episode of adrenal insufficiency.

CONCLUSION

Providing ELBW infants with a daily low dose of long-term hydrocortisone therapy should not lead to a serious suppressive effect on the later function of the HPA axis, regardless of the administration method.

Development of the HPA axis: where and when do sex differences manifest?

Sex differences in the response to stress contribute to sex differences in somatic, neurological, and psychiatric diseases. Despite a growing literature on the mechanisms that mediate sex differences in the stress response, the ontogeny of these differences has not been comprehensively reviewed. This review focuses on the development of the hypothalamic-pituitary-adrenal (HPA) axis, a key component of the body's response to stress, and examines the critical points of divergence during development between males and females. Insight gained from animal models and clinical studies are presented to fully illustrate the current state of knowledge regarding sex differences in response to stress over development. An appreciation for the developmental timelines of the components of the HPA axis will provide a foundation for future areas of study by highlighting both what is known and calling attention to areas in which sex differences in the development of the HPA axis have been understudied.

Sex and life expectancy

BACKGROUND

A sexual dimorphism in human life expectancy has existed in almost every country for as long as records have been kept. Although human life expectancy has increased each year, females still live longer, on average, than males. Undoubtedly, the reasons for the sex gap in life expectancy are multifaceted, and it has been discussed from both sociological and biological perspectives. However, even if biological factors make up only a small percentage of the determinants of the sex difference in this phenomenon, parity in average life expectancy should not be anticipated.

OBJECTIVE

The aim of this review is to highlight biological mechanisms that may underlie the sexual dimorphism in life expectancy.

METHODS

Using PubMed, ISI Web of Knowledge, and Google Scholar, as well as cited and citing reference histories of articles through August 2012, English-language articles were identified, read, and synthesized into categories that could account for biological sex differences in human life expectancy.

RESULTS

The examination of biological mechanisms accounting for the female-based advantage in human life expectancy has been an active area of inquiry; however, it is still difficult to prove the relative importance of any 1 factor. Nonetheless, biological differences between the sexes do exist and include differences in genetic and physiological factors such as progressive skewing of X chromosome inactivation, telomere attrition, mitochondrial inheritance, hormonal and cellular responses to stress, immune function, and metabolic substrate handling among others. These factors may account for at least a part of the female advantage in human life expectancy.

CONCLUSIONS

Despite noted gaps in sex equality, higher body fat percentages and lower physical activity levels globally at all ages, a sex-based gap in life expectancy exists in nearly every country for which data exist. There are several biological mechanisms that may contribute to explaining why females live longer than men on average, but the complexity of the human life experience makes research examining the contribution of any single factor for the female advantage difficult. However, this information may still prove important to the development of strategies for healthy aging in both sexes.

Longitudinal stability and developmental properties of salivary cortisol levels and circadian rhythms from childhood to adolescence

This study aimed to (1) identify a stable, trait-like component to cortisol and its circadian rhythm, and (2) investigate individual differences in developmental trajectories of HPA-axis maturation. Multiple salivary cortisol samples were collected longitudinally across four assessments from age 9 (3rd grade) through age 15 (9th grade) in a community sample of children (N = 357). Sophisticated statistical models examined cortisol levels and its rhythm over time; effects of age, puberty and gender were primarily considered. In addition to situation-specific and stable short-term or epoch-specific cortisol components, there is a stable, trait-like component of cortisol levels and circadian rhythm across multiple years covering the transition from childhood into adolescence. Youth had higher cortisol and flatter circadian rhythms as they got older and more physically developed. Girls had higher cortisol, stronger circadian rhythms, and greater developmental influences across adolescence. Distinguishing a stable, trait-like component of cortisol level and its circadian rhythm provides the empirical foundation for investigating putative mechanisms underlying individual differences in HPA functioning. The findings also provide important descriptive information about maturational processes influencing HPA-axis development.

The interaction of social risk factors and HPA axis dysregulation in predicting emotional symptoms of five- and six-year-old children

OBJECTIVE

We examined the links of social relational (family environment and peer victimization) and neuroendocrinological (HPA axis dysregulation) risk factors to children's emotional symptoms. We placed special emphasis on the joint effects of these risk factors with respect to the emergence and course of the emotional symptoms.

METHODS

One hundred and sixty-six children were interviewed (Berkeley Puppet Interview) at age 5 and 6. Teachers and parents completed the Strengths and Difficulties Questionnaire. Parents completed the Family Environment Scales. Peer victimization was assessed by teacher and child reports. Children's saliva cortisol was measured before and after a highly structured story completion task which targeted their cognitive emotional representations of family conflicts.

RESULTS

In the cross-sectional analyses, negative family environment, peer victimization, and cortisol increase during the story completion task independently contributed to the variance of emotional symptoms. There was a significant interaction effect between family environment and cortisol increase: those six-year-olds who had experienced an unfavorable family environment only showed high levels of emotional symptoms if they exhibited a cortisol increase during the story completion task. In the longitudinal analysis, peer victimization at age 5 predicted an increase of emotional symptoms at age 6, but only for those children who exhibited a blunted cortisol response a year earlier.

CONCLUSIONS

Negative family environment and peer victimization proved to be independently associated with emotional symptoms. HPA axis reactivity differentially moderated these associations. Therapeutic strategies should take the interaction between negative relational experiences and biological susceptibility to stress into account.

Adrenal function in Smith-Lemli-Opitz syndrome

Smith-Lemli-Opitz syndrome (SLOS) is a multiple malformation syndrome due to mutations of the 7-dehydrocholesterol reductase gene (DHCR7), which leads to a deficiency of cholesterol synthesis and an accumulation of 7-dehydrocholesterol. The SLOS clinical spectrum ranges from multiple major malformations to a mild phenotype with minor anomalies and intellectual disability. Several children with SLOS and adrenal insufficiency have been described. We performed ovine corticotropin (oCRH) testing in 35 SLOS patients and 16 age- and gender-matched controls. We reviewed prior adrenocorticotropin (ACTH) stimulation tests of our SLOS patients (19 of 35 available) and reviewed results of ACTH stimulation tests from 10 additional SLOS patients. Results from oCRH testing showed that patients with SLOS had significantly higher ACTH baseline values than healthy controls (24.8 ± 15.3 pg/ml vs. 17.8 ± 7.5 pg/ml, P = 0.034). However, no statistically significant differences were noted for peak ACTH values (74.4 ± 35.0 pg/ml vs. 64.0 ± 24.9 pg/ml, P = 0.303) and for baseline (14.2 ± 7.8 mcg/dl vs. 14.2 ± 6.3 mcg/dl, P = 0.992) and peak cortisol values (28.2 ± 7.9 mcg/dl vs. 24.8 ± 8.1 mcg/dl, P = 0.156). The area-under-the-curve (AUC) was not significantly different in SLOS patients compared to controls for both ACTH (250.1 ± 118.7 pg/ml vs. 195.3 ± 96.6 pg/ml, P = 0.121) as well as cortisol secretion (83.1 ± 26.1 mcg/dl vs. 77.8 ± 25.9 mcg/dl, P = 0.499). ACTH stimulation test results were normal in 28 of 29 tests. The individual with the abnormal test results had subsequent normal oCRH tests. The slightly increased baseline ACTH level seen during oCRH testing may be due to compensated adrenocortical insufficiency. However, we were able to show that our patients with SLOS had an adequate glucocorticoid response, and thus, in mild to moderate cases of SLOS stress steroid coverage may not be warranted.

Sex differences in cortisol response to corticotropin releasing hormone challenge over puberty: Pittsburgh Pediatric Neurobehavioral Studies

OBJECTIVE

Consistent sex differences in regulation of the hypothalamic pituitary adrenocortical (HPA) axis have been shown in animal models and emerge over puberty. However, parallel work in humans is lacking despite implications for elucidating the emergence of sex differences in depression over puberty. We investigated sex differences in HPA response to corticotropin releasing hormone (CRH) challenge over puberty in a carefully screened normative sample.

METHODS

Participants were 68 healthy children (41% girls), ages 6-16, with no personal or family history of psychiatric disorder. Pubertal maturation was determined by Tanner staging. Following 24h of adaptation, 9-10 plasma cortisol samples were collected over 30-40 min pre-infusion baseline, 1 μg/kg CRH infusion, and 90-180 min post-infusion recovery. Thirty-seven participants completed 2+ CRH challenges allowing inclusion of cross-sectional and longitudinal data in all analyses. The influence of gender and pubertal maturation on parameters of cortisol response to CRH challenge was investigated using nonlinear mixed model methodology.

RESULTS

Girls showed increasing total cortisol output following CRH challenge over puberty, while boys showed little change in total cortisol output over puberty. Increased cortisol output in girls was explained by slower reactivity and recovery rates leading to prolonged time to reach peak cortisol and delayed return to baseline over puberty. Girls also showed increasing baseline cortisol over puberty, while boys showed declining baseline over puberty.

CONCLUSION

Results reveal subtle normative sex differences in the influence of pubertal maturation on HPA regulation at the pituitary level. This normative shift may tip the balance towards stress response dysregulation in girls at high risk for depression, and may represent one potential mechanism underlying elevated rates of depression among pubescent girls.

Children suffering from separation anxiety disorder (SAD) show increased HPA axis activity compared to healthy controls

RESEARCH QUESTIONS

Separation anxiety disorder (SAD) is one of the most common mental disorders in childhood, and one of the earliest emerging. Little is known about the association between SAD and the hypothalamic-pituitary-adrenocortical (HPA) axis activity. Therefore, the present study aimed at investigating this association in children suffering from separation anxiety compared to healthy controls.

METHODS

A total of 31 children with diagnosed SAD (mean age: 8.45; 17 females, 14 males) and 25 healthy controls (HC; mean age: 9.74; 12 females, 13 males) took part in the study. All participants underwent psycho-physiological testing for HPA axis challenge. Testing consisted of a separation and a social exposure paradigm. Saliva samples to assess HPA axis-related cortisol secretion were gathered in parallel.

RESULTS

Compared to healthy controls, children with SAD showed greatly increased HPA axis activity, as reflected by an increased cortisol secretion throughout the entire period of investigation. The rise of cortisol was already observed in anticipation of, but not following the separation paradigm. No gender-related differences of cortisol secretion were observed.

CONCLUSIONS

Separation anxiety disorder (SAD) in children is reflected in greatly increased HPA axis activity. Compared to healthy controls, children with SAD showed increased cortisol values from the beginning of, and throughout, the entire investigation. This pattern of results suggests that both the anticipation of a separation and a persistent hyperactivity of the HPA axis system leads to an increased cortisol secretion.

Emanuel Miller Lecture: early onset depressions--meanings, mechanisms and processes

BACKGROUND

Depressive syndromes in children and adolescents constitute a serious group of mental disorders with considerable risk for recurrence. A more precise understanding of aetiology is necessary to improve treatment and management.

METHODS

Three neuroactive agents are purported to be involved in the aetiology of these disorders: serotonin, brain-derived neurotrophic factor and cortisol. A literature review was conducted to determine their contributions to the emergence of unipolar depressions in the adolescent years.

RESULTS

Serotonin, brain-derived neurotrophic factor and cortisol may operate in concert within two distinct functional frameworks: atypical early epigenesis arising in the first few years of life and resulting in the formation of a vulnerable neuronal network involving in particular the amygdala and ventral prefrontal cortex. Individuals with this vulnerability are likely to show impaired mood regulation when faced with environmental demands during adolescence and over the subsequent decades; and acquired neuroendangerment, a pathological brain process leading to reduced synaptic plasticity, in particular in the hippocampus and perhaps the nucleus accumbens and ventral tegmentum. This may result in motivational, cognitive and behavioural deficits at any point in the lifespan most apparent at times of environmental demand.

CONCLUSIONS

The characteristics, course and outcome of a depressive episode may depend on the extent of the involvement of both atypical early neurogenesis and acquired neuroendangerment.

Effects of gender and cigarette smoking on reactivity to psychological and pharmacological stress provocation

We examined the influence of gender and smoking status on reactivity in two human laboratory stress paradigms. Participants were 46 (21 men, 25 women) healthy individuals who completed the Trier Social Stress Task (i.e., performed speech and math calculations in front of an audience) and a pharmacological stress provocation (i.e., administration of corticotrophin releasing hormone (CRH)) after an overnight hospital stay. Approximately half (53%) of the participants were smokers. Cortisol, adrenocorticotrophin hormone (ACTH), physiologic measures (heart rate, blood pressure), and subjective stress were assessed at baseline and at several time points post-task. Men demonstrated higher baseline ACTH and blood pressure as compared to women; however, ACTH and blood pressure responses were more pronounced in women. Women smokers evidenced a more blunted cortisol response as compared to non-smoking women, whereas smoking status did not affect the cortisol response in men. Finally, there was a more robust cardiovascular and subjective response to the Trier as compared to the CRH. Although preliminary, the findings suggest that women may be more sensitive than men to the impact of cigarette smoking on cortisol response. In addition, there is some evidence for a more robust neuroendocrine and physiologic response to acute laboratory stress in women as compared to men.

Hypothalamic-pituitary-adrenocortical (HPA) activity in kindergarten children: importance of gender and associations with behavioral/emotional difficulties

The current cross-sectional study investigated basal and stress-challenged hypothalamic-pituitary-adrenocortical (HPA) system function in 102 five-year old kindergarten children (59 boys, 43 girls) who had been assessed by a comprehensive psychological and behavioral test battery. Baseline HPA system activity was significantly increased in girls when compared to boys (p<0.001). Furthermore, basal HPA system activity predicted a high hormonal release during stress with--again--girls showing higher hormonal responses than boys (p<0.01). Importantly, increased HPA system activity (baseline and stress-challenged) was significantly associated with hyperactivity/impulsivity and emotional problems in boys and with positive emotions in girls (p<0.05). These results suggest an occurrence of neurobiological alterations early in development. The observed neurobiological changes are gender specific already at the age of 5 years. Prospective long-term follow up of the identified subjects with HPA axis alterations will clarify if these markers are predictive for the onset of psychiatric disorders.

HPA axis responses to laboratory psychosocial stress in healthy elderly adults, younger adults, and children: impact of age and gender

Data from five independent studies were reanalyzed in order to investigate the impact of age and gender on HPA axis responses to an acute psychosocial laboratory stress task. The total sample consisted of 102 healthy subjects with 30 older adults (mean age: 67.3 y), 41 young adults (mean age: 23.5 y), and 31 children (mean age: 12.1 y). All participants were exposed to the Trier Social Stress Test (TSST). The stress protocol caused highly significant ACTH and total plasma cortisol responses in older and younger male and female adults (all p<0.0001) as well as salivary free cortisol responses in all six age and gender groups (all p<0.0001). Three-way ANOVAs for repeated measurement were applied to investigate the impact of age and gender on ACTH and cortisol responses. Results showed that the ACTH response to stress was higher in younger adults compared to older adults (main effect: p=0.009, interaction: p=0.06). Post hoc analyses revealed that there was no age effect in the subgroup of women (p=n.s.), while younger men had higher ACTH responses compared to older men (p=0.01). For total plasma cortisol, ANOVA results showed that the pattern of reactivity did not differ between age and gender groups (all interactional effects p=n.s.), although older females had hightened overall cortisol levels compared to the other groups, as proofed in post hoc analyses (all p<0.05). For free salivary cortisol, a significant main effect of gender (p=0.05) and an almost significant three-way-interaction (p=0.09) emerged. Post hoc analyses showed an elevated overall free salivary cortisol response in elderly men compared to elderly women (p=0.006), while no gender differences emerged in neither young adults nor children (both p=n.s.). In sum, the stressor induced significant HPA axis responses in all age and gender groups. The observed ACTH response patterns in young and elderly adults may suggest that a heightened hypothalamic drive in young men decreases with age, resulting in similar ACTH responses in elderly men and women. Alternative interpretations are also discussed. The data also supports the idea of a greater adrenal cortex sensitivity to ACTH signals in young females. Free salivary cortisol responses were elevated in elderly men compared to elderly women, an effect which cannot be explained by gender differences in perceived stress responses to the TSST. It can be speculated if corticosteroid binding globulin (CBG) and/or sex steroids are important modulators of these effects.

Growth hormone response to growth hormone-releasing hormone and clonidine in young monkeys: correlation with behavioral characteristics

Blunted growth hormone (GH) release in response to stimulation by a secretagogue has been widely reported in both children and adults with anxiety and depressive disorders. Blunted GH responsiveness appears to be a stable characteristic of an individual, suggesting that it may be useful as a biological marker that would allow early recognition of these disease processes. Another potential biological marker for anxiety disorders is the temperamental construct of behavioral inhibition. Children identified as being behaviorally inhibited early in life are more likely than less inhibited children to suffer from anxiety disorders later in life (Biederman et al. 1993; Hirshfeld et al. 1992). If blunted GH responsiveness to pharmacological challenge and behavioral inhibition are markers of anxiety and depressive disorders, then it would follow that they would coexist in a subset of individuals. However, such prospective studies in clinically normal young children are difficult to perform. Therefore, in this study, we examined GH responsiveness and temperament in a group of 38 young rhesus monkeys (ages 3-6 months). Monkeys received an intravenous dose of 10 microg/kg of growth hormone-releasing hormone (GHRH) and 5 microg/kg of clonidine, combined, to assess GH response to stimulation. Behavioral reactivity in a fearful situation was assessed using the Human Intruder Test developed by Kalin et al. (1991). This test measures response to a potentially threatening stimulus (a human stranger making direct eye contact). Results showed a population distribution of GH response to GHRH and clonidine ranging from 120 ng/mL/90 minutes to 3,000 ng/mL/90 minutes. There was no difference in GH response in males versus females or any significant effect of age on GH response. There was a significant correlation between GH responsiveness and the time spent reacting to the intruder in the Human Intruder Test. Monkeys with lower GH responsiveness reacted less to the intruder (p < 0.01). Additionally, when monkeys were classified based on their reactivity in the Human Intruder Test, behaviorally nonreactive monkeys had significantly lower GH responsiveness than behaviorally reactive monkeys (p < 0.005). These data provide evidence that there are inherent differences in GH responsiveness to stimulation in young rhesus monkeys and that low GH responsiveness is linked to low behavioral reactivity, which may be a form of behavioral inhibition. Further studies will be necessary to determine if the characteristics of low GH responsiveness and low behavioral reactivity predict an increased propensity to develop anxious or depressive behaviors over the course of the life span.

Resposta Hipofisária-Adrenal ao Teste de Estímulo Com o Hormônio Liberador da Corticotrofina em Crianças Hospitalizadas

O conhecimento da função do eixo hipotalâmico-hipofisário-adrenal (HHA), responsável pela coordenação da resposta ao estresse, em crianças internadas, permite melhor compreensão da resposta neuroendócrina durante o período de internação e doença. Com o objetivo de avaliar essa resposta, estudamos 11 crianças internadas com doenças não-endócrinas e idade média de 5,4 ± 3,3 anos. O teste de estímulo com o hormônio liberador da corticotrofina ovino (CRH; 1 µg/kg IV) foi efetuado às 8:00hs, com dosagens sanguíneas de ACTH e de cortisol basais e 30, 60 e 90 min após o estímulo. Nenhum efeito adverso relacionado ao uso do CRH foi observado. As concentrações basais do ACTH e cortisol estavam elevadas em, respectivamente, 3 e 4 crianças, refletindo provavelmente a resposta do eixo HHA ao estresse. A concentração plasmática basal média do ACTH foi 9,9 ± 8,0 pmol/l e sua concentração máxima média foi 15,1 ± 11,9 pmol/l. Não houve diferença significativa entre as concentrações basais e máximas. A concentração sérica basal média do cortisol foi 725,6 ± 264,9 nmol/dl; a concentração máxima média foi significativamente mais elevada: 1095,3 ± 479,9 nmol/dl (p <0,05). O pico do ACTH precedeu o do cortisol. A ampla variação interindividual observada sugere que a interferência dos fatores individuais e relacionados ao procedimento deva ser considerada para a correta interpretação dos resultados do teste de estímulo com o CRH.

Role of serum cortisol levels in children with asthma

Decreased serum cortisol levels have been proposed to contribute to nocturnal airway obstruction. We investigated whether endogenous cortisol levels are lower, and also whether the 24-h cortisol variation is greater, in children with asthma than in control subjects and assessed the relationship between serum cortisol and nocturnal airflow limitation in children with asthma. Cortisol and FEV(1) were measured every 4 h over 24 h; blood eosinophils, airway responsiveness to methacholine and adenosine 5'-monophosphate (AMP) were measured at 0400 and 1600. Children with asthma had lower cortisol levels than did control subjects; at midnight the difference was significant. Subjects with nocturnal asthma (24-h FEV(1) variation > or =15%) had significantly lower cortisol levels than did control subjects at 0000, 0800, and 1200. A higher mean 24-h cortisol level in subjects with asthma was associated with a significantly higher FEV(1) as a percentage of the predicted value (FEV(1) %pred) at 0400, 0800, and 2000, yet not in control subjects. Higher 24-h cortisol variation was associated with lower FEV(1) %pred at all time points in both control subjects and subjects with nonnocturnal asthma. There was no significant association between the level or variation of cortisol and PD(20) methacholine (provocative dose of methacholine causing a 20% fall in FEV(1)), PD(20) AMP, or eosinophils. Our data suggest that lower cortisol levels contribute to both overall lower levels of FEV(1) especially at night. This may be due to a lack of suppression of airway inflammation.

Development of gender differences in depression: an elaborated cognitive vulnerability-transactional stress theory

Descriptive epidemiological studies are reviewed, showing that the female preponderance in depression begins to emerge around age 13. A developmentally sensitive, elaborated cognitive vulnerability-transactional stress model of depression is proposed to explain the "big fact" of the emergence of the gender difference in depression. The elaborated causal chain posits that negative events contribute to initial elevations of general negative affect. Generic cognitive vulnerability factors then moderate the likelihood that the initial negative affect will progress to full-blown depression. Increases in depression can lead transactionally to more self-generated dependent negative life events and thus begin the causal chain again. Evidence is reviewed providing preliminary support for the model as an explanation for the development of the gender difference in depression during adolescence.

Psychoneuroendocrinology of children and adolescents

This article reviews psychoneuroendocrinologic approaches to the understanding of internalizing disorders (depression and anxiety disorders) and externalizing disorders. This article discusses three specific psychoneuroendocrine systems: measures of the hypothalamic-pituitary-adrenal (HPA) axis, measure of the serotonergic function, and measures of the growth-hormone (GH) response to pharmacologic challenge. The hypothalamic-pituitary-adrenal (HPA) axis is the main system; understanding this system may reveal information on the permissive and etiologic relationship of stress to psychiatric disorder.

Response to oCRH in depressed and nondepressed adolescents: does gender make a difference?

OBJECTIVE

To examine the hypothesis that hypothalamic-pituitary-adrenal responses to stress vary across gender, contributing to gender differences in the prevalence of depression.

METHOD

This study examined gender differences between depressed (n = 21) and control (n = 20) adolescents in adrenocorticotropic hormone (ACTH) and cortisol response to two ovine corticotropin-releasing hormone (oCRH) tests, at baseline and following a cognitive stressor.

RESULTS

Boys had higher (p < .05) measures of ACTH than girls, regardless of depression status, whereas corresponding cortisol parameters were similar in both groups. Cortisol measures were higher (p < .05) at time 1 than at time 2 in both groups, a phenomenon that might reflect the novelty of the situation.

CONCLUSIONS

Gender differences in hormone responses may be related to differences in peripheral metabolism of ACTH, resulting in changes of immunoreactivity but not bioactivity or a different set point of the hypothalamic-pituitary-adrenal axis. The pattern of ACTH and cortisol responses to oCRH and the 24-hour excretion of free cortisol was normal in adolescents with depression, probably reflecting normal negative feedback mechanisms at this age or that most of these patients suffer from atypical rather than melancholic depression.

A comparison of pituitary-adrenal responses to corticotropin-releasing hormone, hypoglycaemia and metyrapone in children with brain tumours and growth hormone deficiency

To assess hypothalamic-pituitary function, a corticotropin-releasing hormone (CRH) stimulation test was performed in nine children following treatment for brain tumours and in 27 growth hormone deficient (GHD) children whose pituitary adrenocorticotropin (ACTH) secretion was normal. In both groups, CRH tests were compared with ACTH and cortisol responses to insulin-induced hypoglycaemia and with ACTH response to metyrapone stimulation. In the patients with brain tumours (five craniopharyngiomas, two suprasellar germinomas, one cerebellar medulloblastoma and one cerebellar ependymoma), ACTH responses to CRH varied greatly with absent or blunted, normal, and exaggerated reactions. Cortisol and ACTH responses were not always correlated. In GHD children but not in children with brain tumours the responses to CRH, insulin tolerance test and metyrapone test were correlated. The marked variability of the CRH test was possibly caused by compounding factors such as preceding corticosteroid therapy, concomitant desmopressin therapy and spontaneous regeneration of damaged brain structures

CONCLUSION

Interpretation of the CRH test to assess hypothalamic-pituitary function in patients with brain tumours is difficult due to compounding factors. Many patients require prolonged follow up with repeated endocrinological evaluation.

Adrenal function following topical steroid treatment in children with atopic dermatitis

Adrenal suppression is a potential complication of topical corticosteroid treatment in atopic dermatitis. We used a low-dose adrenocorticotrophic hormone (ACTH) test (500 ng/1.73 m2) to detect subtle changes in adrenal glucocorticoid function in 14 prepubertal children with moderate or severe atopic dermatitis affecting 16-90% (median 58%) of the body surface area. All had received regular treatment with mild potency BNF (British National Formulary) classification topical corticosteroid ointments (hydrocortisone 48.7-223.2 mg/m2 body surface area/day; median 134.2) for 3-10 years (median 6.5 years). Nine children had also intermittently used moderate potency preparations. However, none had been treated with corticosteroids by any other route in the preceding 6 months. Fourteen prepubertal children with constitutional short stature, without atopic disease, served as controls. The basal, peak, increment and area-under-curve in plasma cortisol concentrations in children with atopic dermatitis were not significantly different from controls, indicating normal adrenal sensitivity to low-dose ACTH. However, the peak in plasma cortisol occurred earlier in children with atopic dermatitis (median 17.5 min) than in controls (median 25 min) (P = 0.02). In addition, there was a significant inverse relationship between time to peak and extent of atopic dermatitis (rs = -0.52; P < 0.05), but not topical steroid treatment dose or score in children with atopic dermatitis. These findings indicate accelerated adrenal responsiveness to ACTH in children with atopic dermatitis, which is independent of treatment. Mild to moderately potent topical corticosteroid ointments in these doses did not suppress adrenal glucocorticoid function in this sample of children with atopic dermatitis.