Assessment of the hypothalamic-pituitary-adrenocortical axis function using a vasopressin stimulation test in neonatal foals.

BACKGROUND: Bacterial sepsis is the leading cause of death in foals and is associated with hypothalamic-pituitary-adrenocortical axis (HPAA) dysfunction. HPAA function can be evaluated by an arginine-vasopressin (AVP) stimulation test. HYPOTHESES/OBJECTIVES: Administration of AVP will stimulate a dose-dependent rise in systemic adrenocorticotropin-releasing hormone (ACTH) and cortisol in neonatal foals. There will be no response seen in corticotropin-releasing hormone (CRH) and baseline AVP will be within reference interval. ANIMALS: Twelve neonatal foals, <72 hours old. METHODS: HPAA function was assessed in foals utilizing 3 doses of AVP (2.5, 5, and 7.5 IU), administered between 24 and 48 hours of age in this randomized cross-over study. Cortisol, ACTH, CRH and AVP were measured at 0 (baseline), 15, 30, 60 and 90 minutes after AVP administration with immunoassays. The fold increase in cortisol and ACTH was calculated at 15 and 30 minutes compared to baseline. RESULTS: All doses of AVP resulted in a significant increase in cortisol concentration over time, and a dose-dependent increase in ACTH concentration over time. ACTH and cortisol were significantly increased at 15 and 30 minutes, respectively after all 3 doses of AVP compared to baseline (P < .01). There was no change in endogenous CRH after stimulation with AVP. CONCLUSION AND CLINICAL IMPORTANCE: Administration of AVP is safe and results in a significant rise in ACTH and cortisol in neonatal foals. A stimulation test with AVP (5 IU) can be considered for HPAA assessment in septic foals.

Child maltreatment and hypothalamic-pituitary-adrenal axis functioning: A systematic review and meta-analysis.

Alterations in hypothalamic-pituitary-adrenal (HPA) axis and its effector hormone cortisol have been proposed as one possible mechanism linking child maltreatment experiences to health disparities. In this series of meta-analyses, we aimed to quantify the existing evidence on the effect of child maltreatment on various measures of HPA axis activity. The systematic literature search yielded 1,858 records, of which 87 studies (k = 132) were included. Using random-effects models, we found evidence for blunted cortisol stress reactivity in individuals exposed to child maltreatment. In contrast, no overall differences were found in any of the other HPA axis activity measures (including measures of daily activity, cortisol assessed in the context of pharmacological challenges and cumulative measures of cortisol secretion). The impact of several moderators (e.g., sex, psychopathology, study quality), the role of methodological shortcomings of existing studies, as well as potential directions for future research are discussed.

Assessment of serum levels of copeptin and corticotropin-releasing factor in children with monosymptomatic and non-monosymptomatic nocturnal enuresis.

BACKGROUND: Nocturnal enuresis is defined as bed-wetting in children from the age of five years that occurs during sleep; if untreated, the condition can result in social and psychological problems both for the children and their parents. Nocturnal enuresis is a complicated disease that includes multiple pathogenetic factors. Nocturnal enuresis is divided into two subgroups: monosymptomatic and non-monosymptomatic. The role of some biomarkers in patients with monosymptomatic enuresis has been reported in a small number of the studies. OBJECTIVE: The aim of this research was to evaluate the serum levels of copeptin and corticotropin-releasing factor (CRF) in monosymptomatic and non-monosymptomatic nocturnal enuresis cases. Although these markers were previously examined in children with monosymptomatic enuresis, there is no study that has evaluated these markers in non-monosymptomatic children. STUDY DESIGN: One hundred nineteen children with nocturnal enuresis (5-16 years) and forty healthy children (5-17 years) were enrolled to the study. Of the nocturnal enuresis group, forty-nine were monosymptomatic and seventy were non-monosymptomatic. Copeptin and CRF were measured by a competitive inhibition method with enzyme-linked immunosorbent assay. RESULTS: The serum copeptin levels were significantly lower in children with monosymptomatic and non-monosymptomatic nocturnal enuresis than in the controls.(median, 34.7 [interquartile range (IQR): 34 pg/ml], 39.8 [IQR: 29 pg/ml] vs 52.1 [IQR: 14 pg/ml], respectively, P < 0.05). The serum CRF levels were significantly lower in children with monosymptomatic and non-monosymptomatic nocturnal enuresis than in the controls (median, 35.1 [IQR: 19 pg/ml], 34.05 [IQR: 24 pg/ml] vs 78.3 [IQR: 39 pg/ml], respectively, P < 0.05). There was no significant difference in copeptin and CRF levels between the children with monosymptomatic and non-monosymptomatic nocturnal enuresis. DISCUSSION: Copeptin is presumed to be a sensitive surrogate biomarker for arginine vasopressin release. To date, there are only two studies in the literature that assess the relationship between copeptin and monosymptomatic enuresis. The only study in the literature demonstrated significantly decreased levels of CRF in monosymptomatic enuretic children. It was demonstrated that the levels of copeptin and CRF differ in both children with monosymptomatic and non-monosymptomatic nocturnal enuresis from the control groups. It was also demonstrated that copeptin and CRF levels were not different between the children in monosymptomatic and non-monosymptomatic groups. CONCLUSION: Those changes in both copeptin and CRF which were shown in this study in monosymptomatic and non-monosymptomatic enuretic children may contribute to the pathogenesis of nocturnal enuresis. Further case-control studies can evaluate the copeptin and CRF levels before treatments in monosymptomatic and non-monosymptomatic patients to decide potential effectiveness of treatment.

Assessment of ventral tegmental area-projecting GABAergic neurons from the bed nucleus of the stria terminalis in modulating binge-like ethanol intake.

Corticotropin-releasing factor (CRF) circuitry is a key component in plasticity underlying the transition to ethanol (EtOH) dependence. We have previously shown that chemogenetic silencing of CRF neurons stemming from the dorsolateral bed nucleus of the stria terminalis (dlBNST) and projecting to the ventral tegmental area (VTA) significantly blunts binge-like EtOH consumption. While CRF neurons in the BNST are thought to entail primarily a GABA phenotype, glutamatergic neurons within the BNST also innervate the VTA and influence consummatory behaviors. Here, we combined the well-validated Vgat-ires-Cre transgenic mice with chemogenetic tools to extend our previous findings and corroborate the contribution of the VTA-projecting dlBNST GABAergic circuitry in modulating binge-like EtOH consumption using "drinking-in-the-dark" procedures. Mice were given bilateral injection of Gi-coupled chemogenetic viral vector (or control virus) into the dlBNST and bilateral cannulae into the VTA. On test day, clozapine-N-oxide (CNO; or vehicle) was infused directly into the VTA to silence VTA-projecting dlBNST neurons and subsequent binge-like EtOH consumption was assessed. We then used immunohistochemistry (IHC) to determine the co-expression of CRF and viral vector. Our results showed that relative to vehicle treatment or CNO treatment in mice expressing the control virus, silencing VTA-projecting dlBNST GABAergic neurons by CNO treatment in mice expressing Gi-coupled chemogenetic virus significantly reduced binge-like EtOH intake. This effect was not seen with sucrose consumption. Our IHC results confirm a population of CRF-expressing GABAergic neurons within the dlBNST. This study directly establishes that VTA-projecting GABAergic neurons of the dlBNST modulate binge-like EtOH consumption.

Assessment of serum level of corticotropin-releasing factor in primary nocturnal enuresis.

INTRODUCTION: Primary nocturnal enuresis is one of the sleep related phenomena characterized by disruption in the relationship between arousal and urination. Corticotropin-releasing factor (CRF) is a neurohormone released from the paraventricular nucleus of the hypothalamus into the median eminence to elicit release of adrenocorticotrophin from the anterior pituitary. It may act to modulate autonomic function and behavior in concert with the endocrine effects. Conflicting animal studies about the role of CRF in micturition, either facilitating or inhibiting, have been raised. It was suggested to be a novel target for treatment of urinary disorders based on the finding that manipulation of CRF in the pontine micturition circuit could affect urodynamic function. AIM: The aim was to throw light on the possible role of CRF in primary monosymptomatic nocturnal enuresis by assessing its serum level. SUBJECTS AND METHODS: Twenty-nine children aged 8-14 years complaining of primary monosymptomatic nocturnal enuresis and 16 age- and sex-matched healthy children with good toilet control day and night were recruited to the study. History taking, clinical examination, and assessment of serum CRF levels in the morning and evening (9 a.m. and 9 p.m.) were carried out for all patients and controls. RESULTS AND DISCUSSION: A positive family history of enuresis was detected in 82.8% of enuretic patients. Serum levels of CRF (both morning and evening) were significantly lower in patients than in controls. Several animal studies suggested that CRF in descending projections from Barrington's nucleus to the lumbosacral parasympathetic neurons is inhibitory to micturition, which supports our results and the assumption that reduction of the evening serum CRF level could have a role in the occurrence of primary monosymptomatic nocturnal enuresis. No significant difference was found between morning and evening CRF serum levels in either cases or controls, which negates our assumption of having a rhythmic pattern of release (figure). No correlations with age were found. According to their history, all our enuretic patients were deep sleepers. Deep sleep and difficult arousal were found to have a major role in primary monosymptomatic nocturnal enuresis. It was proposed that CRF function may allow arousal to occur before micturition to facilitate preparative behaviors. A lower CRF level may explain deep-sleep pattern in children with enuresis. CONCLUSION: CRF was deficient in our enuretic children, which may draw attention to the possible pathophysiological implications in primary nocturnal enuresis (either at the level of loss of inhibitory effect on micturition or lack of arousal in response to bladder distension). Further proof studies are recommended.

Intra-Individual Consistency in Endocrine Profiles Across Successive Pregnancies.

CONTEXT: It is yet unknown how similar women's hormone levels are during successive pregnancies, and very little is known about the degree to which siblings experience similar prenatal environments. Given the importance of understanding how women's reproductive life histories exert cumulative effects on health via hormone exposure, and the importance of understanding how fetal programming via endocrine signaling affects sibling trait concordance, here, we address this important lacuna in the literature. OBJECTIVE: This study aimed to investigate how consistent women's hormone profiles are across two successive pregnancies. DESIGN AND MAIN OUTCOME MEASURES: This longitudinal, prospective study followed a cohort of 28 women across two pregnancies (PREG 1 and PREG 2). Women's circulating hormone levels were assessed from blood samples at 25, 31, and 37 weeks' gestation for adrenocorticotropic hormone (ACTH), placental corticotropin-releasing hormone (pCRH), cortisol, estradiol, and progesterone. ACTH and cortisol levels were assessed 3 months postpartum. Research questions include: Are hormone levels in PREG 2 significantly different from levels in PREG 1? What proportion of variance in PREG 2 hormone levels is attributable to variance in PREG 1 levels? Are hormone levels more stable between PREG 1 and PREG 2 compared with postpartum phases following these pregnancies? Is pCRH, which is completely placentally derived, less similar than other hormones across successive pregnancies? PARTICIPANTS AND SETTING: Pregnant women attended study visits at a university psychobiology laboratory in Southern California. RESULTS AND CONCLUSIONS: Comparisons of hormone concentrations across women's successive pregnancies via paired t test revealed substantial consistency from one pregnancy to another, with only significant differences between pregnancies for pCRH. Regressions revealed substantial predictability from one pregnancy to another, with between 17-56% of PREG 2 variances accounted for by PREG 1 values. Women exhibited lower degrees of consistency and predictability in hormone levels across postpartum phases compared with gestational concentrations. This is the first study to describe maternal and placental hormone levels across successive pregnancies.

Association between polymorphisms of the CRH and POMC genes with economic traits in Korean cattle (Hanwoo).

The corticotrophin-releasing hormone (CRH) and proo-piomelanocortin (POMC) genes are considered to play an important role in the growth and development of mammals. In this study, the bovine CRH and POMC genes were characterized to detect genetic variation at these loci in relation to economic traits in Korean cattle (Hanwoo). Nine single nucleotide polymorphisms (SNPs; C148T, A186G, A234C, G269A, G1030A, G1084A, A1136C, G1179C, and A1439G) were detected in the CRH gene, and six SNPs (C7017T, A7027T, C7050T, G7063T, C7160T, and C7221T) were detected in the POMC gene. Three SNPs in the CRH gene (G1030A, G1084A, and G1179C) were missense mutations, and three SNPs in the POMC gene (C7017T, A7027T, and C7160T) were missense mutations. Statistical analysis indicated that one CRH polymorphism (G1084A) was signifi-cantly (P = 0.05) associated with the longissimus dorsi muscle area (LMA), and a POMC polymorphism (C7221T) significantly influenced LMA and marbling scores. A significant interaction was detected be-tween CRH and POMC in relation to carcass weight and LMA. These results indicate that CRH and POMC may be candidate genes for car-cass traits, and suggest that the interaction between CRH and POMC strongly affects carcass traits in cattle.

FGF21 acts centrally to induce sympathetic nerve activity, energy expenditure, and weight loss.

The mechanism by which pharmacologic administration of the hormone FGF21 increases energy expenditure to cause weight loss in obese animals is unknown. Here we report that FGF21 acts centrally to exert its effects on energy expenditure and body weight in obese mice. Using tissue-specific knockout mice, we show that ßKlotho, the obligate coreceptor for FGF21, is required in the nervous system for these effects. FGF21 stimulates sympathetic nerve activity to brown adipose tissue through a mechanism that depends on the neuropeptide corticotropin-releasing factor. Our findings provide an unexpected mechanistic explanation for the strong pharmacologic effects of FGF21 on energy expenditure and weight loss in obese animals.

Assessment of T regulatory cells and expanded profiling of autoantibodies may offer novel biomarkers for the clinical management of systemic sclerosis and undifferentiated connective tissue disease.

In order to identify disease biomarkers for the clinical and therapeutic management of autoimmune diseases such as systemic sclerosis (SSc) and undifferentiated connective tissue disease (UCTD), we have explored the setting of peripheral T regulatory (T reg) cells and assessed an expanded profile of autoantibodies in patients with SSc, including either limited (lcSSc) or diffuse (dcSSc) disease, and in patients presenting with clinical signs and symptoms of UCTD. A large panel of serum antibodies directed towards nuclear, nucleolar, and cytoplasmic antigens, including well-recognized molecules as well as less frequently tested antigens, was assessed in order to determine whether different antibody profiles might be associated with distinct clinical settings. Beside the well-recognized association between lcSSc and anti-centromeric or dcSSC and anti-topoisomerase-I antibodies, we found a significative association between dcSSc and anti-SRP or anti-PL-7/12 antibodies. In addition, two distinct groups emerged on the basis of anti-RNP or anti-PM-Scl 75/100 antibody production among UCTD patients. The levels of T reg cells were significantly lower in patients with SSc as compared to patients with UCTD or to healthy controls; in patients with lcSSc, T reg cells were inversely correlated to disease duration, suggesting that their levels may represent a marker of disease progression.

S6K1 in the central nervous system regulates energy expenditure via MC4R/CRH pathways in response to deprivation of an essential amino acid.

It is well established that the central nervous system (CNS), especially the hypothalamus, plays an important role in regulating energy homeostasis and lipid metabolism. We have previously shown that hypothalamic corticotropin-releasing hormone (CRH) is critical for stimulating fat loss in response to dietary leucine deprivation. The molecular mechanisms underlying the CNS regulation of leucine deprivation-stimulated fat loss are, however, still largely unknown. Here, we used intracerebroventricular injection of adenoviral vectors to identify a novel role for hypothalamic p70 S6 kinase 1 (S6K1), a major downstream effector of the kinase mammalian target of rapamycin, in leucine deprivation stimulation of energy expenditure. Furthermore, we show that the effect of hypothalamic S6K1 is mediated by modulation of Crh expression in a melanocortin-4 receptor-dependent manner. Taken together, our studies provide a new perspective for understanding the regulation of energy expenditure by the CNS and the importance of cross-talk between nutritional control and regulation of endocrine signals.

Adrenocorticotropic hormone and cortisol response to corticotropin releasing hormone in the critically ill-a novel assessment of the hypothalamic-pituitary-adrenal axis.

BACKGROUND: The pathophysiology of adrenal insufficiency, common in surgical intensive care units, has not been fully elucidated. METHODS: Patients at risk (age > 55 years, in the surgical intensive care unit >1 week, baseline cortisol < 20 µg/dL) were enrolled. After measuring cortisol and adrenocorticotropic hormone (ACTH), corticotropin-releasing hormone (CRH) was administered. ACTH and cortisol were measured over 120 minutes. Short and long cosyntropin stimulation tests determined adrenal function. Area under the curve (AUC) and mixed linear models were used to compare cortisol and ACTH responses. Patients were grouped according to survival and response to stimulation testing. Chi-square and t tests were performed, and P values < .05 were considered statistically significant. RESULTS: Six of 25 patients responded poorly to cosyntropin, and 5 died compared with 3 after a normal response (P < .01). ACTH (AUC) and ACTH peak were increased in nonsurvivors after CRH administration. Cortisol peak and AUC were not different. CONCLUSIONS: ACTH responsiveness was increased in nonsurvivors and may predict mortality.

Chronological assessment of mast cell-mediated gut dysfunction and mucosal inflammation in a rat model of chronic psychosocial stress.

Life stress and mucosal inflammation may influence symptom onset and severity in certain gastrointestinal disorders, particularly irritable bowel syndrome (IBS), in connection with dysregulated intestinal barrier. However, the mechanism responsible remains unknown. Crowding is a validated animal model reproducing naturalistic psychosocial stress, whose consequences on gut physiology remain unexplored. Our aims were to prove that crowding stress induces mucosal inflammation and intestinal dysfunction, to characterize dynamics in time, and to evaluate the implication of stress-induced mast cell activation on intestinal dysfunction. Wistar-Kyoto rats were submitted to 15 days of crowding stress (8 rats/cage) or sham-crowding (2 rats/cage). We measured spontaneous and corticotropin-releasing factor-mediated release of plasma corticosterone. Stress-induced intestinal chrono-pathobiology was determined by measuring intestinal inflammation, epithelial damage, mast cell activation and infiltration, and intestinal barrier function. Corticosterone release was higher in crowded rats throughout day 15. Stress-induced mild inflammation, manifested earlier in the ileum and the colon than in the jejunum. While mast cell counts remained mostly unchanged, piecemeal degranulation increased along time, as the mucosal content and luminal release of rat mast cell protease-II. Stress-induced mitochondrial injury and increased jejunal permeability, both events strongly correlated with mast cell activation at day 15. Taken together, we have provided evidences that long-term exposure to psychosocial stress promotes mucosal inflammation and mast cell-mediated barrier dysfunction in the rat bowel. The notable resemblance of these findings with those in some IBS patients, support the potential interest and translational validity of this experimental model for the research of stress-sensitive intestinal disorders, particularly IBS.

Vasopressinergic network abnormalities potentiate conditioned anxious state of rats subjected to maternal hyperthyroidism.

We have previously reported that a mild maternal hyperthyroidism in rats impairs stress coping of adult offspring. To assess anxiogenesis in this rat model of stress over-reactivity, we used two behavioural tests for unconditional and conditional anxious states: elevated plus maze test (EPM) and Vogel conflict test (VCT). In the latter one, arginine vasopressin (AVP) release was enhanced due to osmotic stress. With the EPM test no differences were observed between maternal hyperthyroid rats (MH) and controls. However, with the VCT, the MH showed increased anxiety-like behaviour. This behavioural difference was abolished by diazepam. Plasma AVP concentration curve as a function of water deprivation (WD) time showed a marked increase, reaching its maximal levels within half the time of controls and another significant difference after VCT. A general increase in Fos expression in hypothalamic supraoptic and paraventricular nuclei (PVN) was observed during WD and after VCT. There was also a significant increase of AVP immunoreactivity in anterior hypothalamic area. A large number of Herring bodies were observed in the AVP containing fibres of MH hypothalamic-neurohypophysial system. Numerous reciprocal synaptic connections between AVP and corticotropin releasing factor containing neurons in MH ventromedial PVN were observed by electron microscopy. These results suggest that a mild maternal hyperthyroidism could induce an aberrant organization in offspring's hypothalamic stress related regions which could mediate the enhanced anxiety seen in this animal model.

Levels of maternal serum corticotropin-releasing hormone (CRH) at midpregnancy in relation to maternal characteristics.

BACKGROUND: Corticotropin-releasing hormone (CRH) in maternal blood originates primarily from gestational tissues and elevated levels in midpregnancy have been linked to adverse pregnancy outcomes. Investigators have hypothesized that high levels of maternal stress might lead to elevated CRH levels in pregnancy. Yet a few studies have measured maternal CRH levels among subgroups of women who experience disproportionate socioeconomic disadvantage, such as African-American and Hispanic women, and found that these groups have lower CRH levels in pregnancy. Our goal was to identify maternal characteristics related to CRH levels in midpregnancy and examine which if any of these factors help to explain race differences in CRH levels. METHODS: The Pregnancy Outcomes and Community Health (POUCH) Study prospectively enrolled women at 15-27 weeks' gestation from 52 clinics in five Michigan communities (1998-2004). Data from the POUCH Study were used to examine maternal demographics, anthropometrics, health behaviors, and psychosocial factors (independent variables) in relation to midpregnancy blood CRH levels modeled as logCRHpg/ml (dependent variable). Analyses were conducted within a sub-cohort from the POUCH Study (671 non-Hispanic Whites, 545 African-Americans) and repeated in the sub-cohort subset with uncomplicated pregnancies (n=746). Blood levels of CRH and independent variables were ascertained at the time of enrollment. All regression models included week of enrollment as a covariate. In addition, final multivariate regression models alternately incorporated different psychosocial measures along with maternal demographics and weight. Psychosocial variables included measures of current depressive symptoms, perceived stress, coping style, hostility, mastery, anomie, and a chronic stressor (history of abuse as a child and adult). RESULTS: In sub-cohort models, the adjusted mean log CRH level was significantly lower in African-Americans vs. non-Hispanic Whites; the difference was -0.48pg/ml (P<0.01). This difference was reduced by 21% (-0.38pg/ml, P<0.01) after inclusion of other relevant covariates. Adjusted mean log CRH levels were also lower among women with <12 years vs. >or=12 years of education (minimal difference=-0.19pg/ml, P<0.05), and among women with high levels of depressive symptoms who did not use antidepressants vs. women with lower levels of depressive symptoms and no antidepressant use (minimal difference=-0.13pg/ml, P<0.01). Log CRH levels were inversely associated with maternal weight (-0.03pg/ml per 10 pound increase, P<.05) but unrelated to smoking and all other psychosocial measures. Results were similar in the subset of women with uncomplicated pregnancies, except that lower CRH levels were also linked to higher perceived stress. CONCLUSION: African-American women have lower blood CRH levels at midpregnancy and the race difference in CRH levels is reduced modestly after adjustment for other maternal characteristics. CRH levels were not elevated among women with high levels of perceived stress or more chronic stressors. The inverse association between CRH levels and maternal weight is likely due to a hemodilution effect. Relations among maternal CRH levels and maternal race, educational level, and depressive symptoms are difficult to explain and invite further investigation. Our results highlight a group of covariates that merit consideration in studies that address CRH in the context of pregnancy and/or post-partum complications.

Conceptualizing child health disparities: a role for developmental neurogenomics.

Biological, psychological, and social processes interact over a lifetime to influence health and vulnerability to disease. Those interested in studying and understanding how and why racial/ethnic and social disparities emerge need to focus on the intersection of these processes. Recent work exploring molecular epigenetic mechanisms of gene expression (in humans as well and other mammalian systems) has provided evidence demonstrating that the genome is subject to regulation by surrounding contexts (eg, cytoplasmic, cellular, organismic, social). The developing stress axis is exquisitely sensitive to regulation by social forces represented at the level of the epigenome. Old assumptions about an inert genome are simply incorrect. Epigenetic processes may provide the missing link that will allow us to understand how social and political conditions, along with individual subjective experiences, can directly alter gene expression and thereby contribute to observed social inequalities in health. Developmental neurogenomics may provide the direct link between the biological and social/psychological worlds. These biological mechanisms of plasticity (at the level of gene expression and regulation) may play a profound role in how we conceptualize health inequalities by informing our concepts regarding the somatization or embodiment of social inequalities.

Bioassay research methodology: measuring CRH in pregnancy.

BACKGROUND: There are documented associations between elevated maternal corticotropin-releasing hormone (CRH) levels and adverse pregnancy outcomes. However, reports of these findings often lack sufficient detail and rationale regarding the bioassay methodology. This shortcoming can be problematic for researchers who do not possess in-depth laboratory sciences knowledge but who want to include bioassays in their investigations or to evaluate published reports. The quality and reliability of CRH measurement results can be significantly affected by variables encountered during sample collection, processing, storage, and bioassay. Thus, it is important to establish research laboratory protocols that are based on well-informed rationales and to carefully consider and control for relevant variables. APPROACH: A synthesis of laboratory sciences literature regarding variables affecting CRH measurement in pregnancy is presented. Additionally, consultation with experienced researchers provided an in-depth understanding of CRH measurement. From these sources, a laboratory protocol for clinical research was developed. RESULTS: Multiple variables that are specific to the reliability of CRH measurement in pregnancy have been identified. These include sample collection methods, sample processing, sample integrity, sample storage, and the actual assay selected. CONCLUSION: The reliability of CRH measurements can be significantly improved by identifying and controlling for variables encountered during sample collection, processing, storage, and bioassay. Adequate methodological details are difficult to glean solely from the published literature, thus consultation with well-informed researchers is necessary. A protocol for CRH bioassay in clinical research is proposed.

Role of corticotropin-releasing hormone testing in assessment of hypothalamic-pituitary-adrenal axis function in infants with congenital central hypothyroidism.

CONTEXT: The Dutch neonatal congenital hypothyroidism (CH) screening program detects infants with CH of central origin (CH-C). These infants have a high likelihood of multiple pituitary hormone deficiencies. ACTH deficiency especially poses an additional risk for brain damage and may be fatal. OBJECTIVE: Our objective was to evaluate different tools for assessment of the integrity of the hypothalamus-pituitary-adrenocortex (HPA) axis in young infants, aiming for a strategy for reliable and timely diagnosis. DESIGN, SETTING: This is a Dutch nationwide prospective study (enrollment 1994-1996). Patients were included if neonatal CH screening results were indicative of CH-C and HPA axis function could be tested within 6 months of birth. PATIENTS: Nine male and three female infants with CH-C and four infants with false-positive screening results or transient hypothyroidism were included in the study. MAIN OUTCOME MEASURES: CRH test results, multiple cortisol plasma concentrations, and cortisol excretion in 24-h urine were measured. RESULTS: Six (50%) of the CH-C patients had abnormal CRH test results. Three of them had discordant test results: impaired increase of plasma cortisol in response to CRH, despite substantial increase of plasma ACTH. The other three infants, with concordant impaired responses of both ACTH and cortisol to CRH, had a very low urinary cortisol excretion in comparison with the subjects with normal CRH test results. CONCLUSIONS: The CRH test proves to be a fast and reliable tool in the assessment of HPA axis (dys)function. It enables timely diagnosis in (asymptomatic) neonates at risk for serious morbidity and mortality. The discordant response type, which has not been described before, may be an early phase of HPA axis dysfunction. Alternatively, patients with this response type may constitute a separate pathogenetic subset of HPA axis-deficient patients.