Injection Of Corticotropin-releasing Hormone Research Articles

The role of bilateral inferior petrosal sinus sampling in determining the preoperative localization of ACTH-secreting pituitary microadenomas in Cushing's disease: Experience of a tertiary center

IntroductionBilateral inferior petrosal sinus sampling (BIPSS) is an important procedure in the diagnostic work-up of Cushing’s syndrome (CS). In this study, we investigated the diagnostic performance of BIPSS in detecting the source of adrenocorticotropic hormone (ACTH) secretion in Cushing's disease (CD) without radiological evidence. MethodsThirty-five consecutive patients who underwent BIPSS due to ACTH-dependent CS between 2010 and 2019 in our clinic and subsequently underwent transsphenoidal surgery were included. The indication for BIPSS was biochemically proven ACTH-dependent CS but normal or ≤6 mm pituitary lesion in pituitary magnetic resonance imaging (MRI). Corticotropin releasing hormone (CRH) stimulation was applied to all patients during the BIPSS procedure. BIPSS data, MRI results, pathological findings, and follow-up results were analyzed. The diagnostic performance of BIPSS was calculated. ResultsA total of 35 patients, 6 (17%) males and 29 (83%) females, were included in the study. Pituitary MRI was normal in 12 (34.3%) and revealed lesions ≤ 6 mm in 23 (65.7%) patients. BIPSS lateralized the right side in 13 (37.1%) and left side in 18 (51.4%) patients, while no lateralization was observed in the remaining 4 (11.5%) patients. BIPSS showed lateralization in the same direction with pituitary adenoma in 21 (60%) patients before CRH injection and in 29 (83%) patients after CRH injection (p = 0.034). The sensitivity of the BIPSS procedure was 88%. Accurate localization of the pituitary lesion was more frequent when based on BIPSS results than on MRI (83% vs. 51%, P = 0.005). ConclusionBIPSS appears to be a valuable and safe diagnostic tool in patients who are diagnosed with CD biochemically but do not have clear radiological evidence of ACTH-producing lesion.

The Dexamethasone-CRH Stimulation Test: A Single-Center Experience

Background: The diagnostic value of adding a Corticotropin Releasing Hormone (CRH) Stimulation Test to the 2-day Low Dose Dexamethasone Suppression Test (Dex-CRH Test) has been debated in the literature. We hypothesized that adding CRH to LDDST would provide additional case detection in patients suspected of having Cushing’s disease (CD). Methods: We identified 118 patients who underwent the Dex-CRH test to evaluate ACTH-dependent CS from a prospectively maintained pituitary database over 12 years. Seven patients were excluded (2 lost to follow up, 2 were on Dilantin with no available Dexamethasone (Dex) level, 2 had cyclic CD, and 1 suspected noncompliance with Dex intake). Three patients with ectopic ACTH Syndrome had very high cortisol levels after both LDDST and Dex-CRH tests. The remaining 108 patients are the subjects of this analysis. Patients were instructed to take 8 doses of Dex 0.5 mg PO every 6 hours starting at noon with the last dose of Dex taken at 6 AM. Ovine CRH injection (1 µg/kg, max 100 mcg) was given IV 2 hours afterwards. Cortisol was measured 2 hours after the last Dex dose prior to and 15 minutes after CRH administration. CD diagnosis was made based on positive ACTH staining on pituitary pathology and/or development of hypocortisolism postoperatively. Patients with no Cushing disease (NCD) are the group of patients in whom CD diagnosis could not be confirmed after a minimum follow up of 30 months. Results: Among 108 patients who underwent Dex-CRH test, 66 had CD and 42 had NCD. The female sex ratio, and median (range) for each of age, BMI, and follow-up duration in months were as follows with no statistically significant difference between the two groups: CD: 83%, 40 (15–82), 34 (30–42) and 63 (24–102). NCD: 88%, 40 (20–71), 37 (31–43) and 52 (30–67). Among 66 patients with CD, 5 patients (7.6%) had a cortisol level ≤ 1.4 µg/dl after LDDST but were appropriately classified as CD with a cortisol level >1.4 µg/dL at 15-min post CRH stimulation. In contrast, 3/42 patients (7.1%) in NCD had an abnormal Dex-CRH test. In only one of these three patients the LDDST was normal (cortisol post-Dex was 1.4 µg/dL and increased to 3.1 µg/dL 15-min post CRH). A cortisol cut-off value of > 1.4 µg/dL at 15 min during Dex-CRH test provided a sensitivity of 100%, specificity of 93%, and diagnostic accuracy of 97% to diagnose CD. When patients without a Dex level were excluded from the analysis (n=74), the sensitivity did not change but specificity and accuracy of Dex-CRH test further increased to 97% and 99%, respectively. Conclusion: The CRH test addition to the 2-day LDDST provided additional case detection in 5/66 (7.6%) of patients with CD. It resulted in one additional false-positive case compared to LDDST. Measurement of Dex level provided improved diagnostic accuracy of DEX-CRH test.

Comparative Study of CRH Microinjections into PVN and CeA Nuclei on Food Intake, Ghrelin, Leptin, and Glucose Levels in Acute Stressed Rats

Introduction:Corticotropin-Releasing Hormone (CRH) is involved in stress and energy homeostasis. On the other hand, CRH receptors also exist within the paraventricular nucleus (PVN) and Central Amygdala (CeA) nuclei. The present study compared the effect of CRH microinjections into PVN and CeA on three consecutive hours and cumulative food intake, internal regulatory factors of food intake, such as serum leptin and ghrelin, as well as blood glucose levels in rats under different acute psychological (Social Stress [SS] and Isolation Stress [IS] group) stresses.Methods:Sixty-six male Wistar rats were randomly allocated to 11 groups: Control, Sham, CRH-PVN, CRH-CeA, SS, IS, SS-CRH-PVN, SS-CRH-CeA, IS-CRH-PVN, and IS-CRH-CeA groups. The CRH (2 µg/kg in 0.5 µL saline) was injected into PVN and CeA nuclei in rats under everyday, acute social stress and isolation stress conditions.Results:Acute isolation and social stresses did not affect cumulative food intake. Whereas isolation stress led to changes in both leptin and glucose levels, social stress reduced only glucose levels. Cumulative food intake significantly decreased under acute CRH injection into the CeA and particularly into the PVN. Blood glucose significantly reduced in all the groups receiving CRH into their CeA.Conclusion:The PVN played a more important role compared to CeA on food intake. These nuclei probably employ different mechanisms for their effects on food intake. Besides, it seems that exogenously CRH injection into the PVN probably had a more anorectic effect than naturally activated CRH by stresses. Acute isolation stress had a greater impact than social stress on leptin level and cumulative food intake. Thus, elevated food intake related to leptin compared to ghrelin and glucose levels in the CRH-PVN group under acute social stress.

Relationship between sympathoadrenal and pituitary-adrenal response during colorectal distention in the presence of corticotropin-releasing hormone in patients with irritable bowel syndrome and healthy controls.

Corticotropin-releasing hormone (CRH) mediates stress responses in the brain-gut axis. Administration of CRH modulates brain activation, for example by controlling the autonomic nervous system in response to colorectal distention. Here, we investigated the relationship between sympathoadrenal and hypothalamic-pituitary-adrenal (HPA) responses to colorectal distention in patients with irritable bowel syndrome (IBS). We enrolled 32 patients with IBS (16 women and 16 men) and 32 healthy subjects (16 women and 16 men), and randomly divided them between CRH and saline injection groups. The patients randomly underwent no (0 mmHg), mild (20 mmHg), or strong (40 mmHg) colorectal distension. CRH (2 μg/kg) or saline was then administered via injection, and the distention protocol was repeated. The heart rate (HR) and HR variability (HRV; calculated as the low [LF] to high frequency [HF] peak ratio, LF/HF) were analyzed using electrocardiography. Plasma noradrenaline, adrenaline, adrenocorticotropic hormone (ACTH), and cortisol levels were measured at the time of each distention. Plasma adrenaline levels were shown to be associated with plasma ACTH levels in HCs injected with CRH during distention using structural equation modeling analysis. Patients with IBS injected with placebo during distention displayed a closer association between these two parameters than those injected with CRH. Generalized estimating equation analysis revealed a significant distention × group × drug interaction for HF power. Moreover, there was a strong correlation between adrenaline and HRV upon CRH injection in controls, but not patients with IBS. The relationship between HPA-sympathoadrenal responses and CRH levels during colorectal distention differs between patients with IBS and controls. Modulation of adrenal gland activity in response to ACTH stimulation may contribute to the brain-gut pathophysiology characteristic of IBS.

Intravenous Corticotropin-releasing Hormone Administration Increases Esophageal Electrical Sensitivity in Healthy Individuals.

Background/AimsWhen a person is experiencing stress, corticotropin-releasing hormone (CRH) can modulate gut physiologies, such as visceral sensation or gastrointestinal motility, and its intravenous administration mimics stress-induced physiological changes. However, the influence of CRH on the esophagus is yet unknown. Accordingly, we investigated whether intravenous CRH administration increases esophageal sensitivity to electrical stimulation in healthy Japanese subjects.MethodsTwenty healthy subjects were recruited. We quantified the initial perception threshold (IPT) every 15 minutes after CRH injection. Venous blood was collected with a cannula, and both plasma adrenocorticotropic hormone (ACTH) and cortisol were measured at pre-stimulation, 0, 30, 60, 90, and 120 minutes. The results from each time point were compared against a baseline IPT obtained before electrical stimulation was initiated.ResultsWhen compared to the baseline IPT value (16.9 ± 4.5), CRH significantly decreased electrical threshold of the esophagus at 30, 45, 60, 75 minutes (14.1 ± 4.2, 13.1 ± 5.0, 12.1 ± 5.7, 14.0 ± 5.8 minutes, P < 0.01, respectively) after CRH injection, suggesting that CRH increased esophageal sensitivity to the electrical stimulus. CRH also significantly increased plasma ACTH levels at 30 minutes (50.3 ± 17.7, P < 0.01), and cortisol levels at 30 minutes (22.0 ± 6.7 minutes, P < 0.01) and 60 minutes (20.3 ± 6.7 minutes, P < 0.01) after CRH injection, when compared to the pre-stimulation ACTH and cortisol values.ConclusionIntravenous CRH administration increased esophageal electrical sensitivity in normal subjects, emphasizing the important role of stress in esophageal sensitivity.

Effect of in ovo injection of corticotropin-releasing hormone on the timing of hatching in broiler chickens

In chicken embryos, intravenous injection of corticotropin-releasing hormone (CRH) causes the release of both corticosteroids and thyroid hormones. These hormones initiate and enhance the hatching process, raising the possibility that CRH treatment of the late chicken embryo could accelerate hatching and/or decrease the spread of hatching. We performed a series of exploratory tests to investigate whether in ovo delivery methods of CRH other than intravenous injection that are more practical in a commercial setting, affect hatching time in broilers. Corticotropin-releasing hormone was injected into the air cell, albumen, or amniotic fluid of broiler breeder eggs, in the last week of embryonic development. Average incubation duration was significantly decreased by 22 h when 2 μg of CRH was injected into the air cell on embryonic day 18 (E18) of Cobb eggs. Acceleration of hatching (but only by 8 h) was also seen for Ross chicks when CRH was injected daily into the albumen between E10 and E18. However, repeats of both experiments did not show consistent effects of CRH on hatching time; in most experiments performed, CRH did not affect hatching time. We speculate that the effectiveness of CRH uptake via these delivery methods and/or the duration and magnitude of the thyroxine and corticosterone response to CRH is not sufficient to have a substantial effect on hatching time. We therefore conclude that in ovo CRH treatment does not seem a feasible option as a practical tool to increase hatchery productivity or to investigate the effects of CRH agonists and antagonists on hatching.

Plasma cortisol response cannot be classically conditioned in a taste-endocrine paradigm in humans.

Peripheral immune responses can be modified by associative learning procedures. Less is known, however, whether and to what extent neuroendocrine parameters can be classically conditioned. In this randomized double-blind study, we modified an established paradigm to behaviorally condition endocrine responses in humans. Thirty-one healthy male participants received a distinctively flavored green drink as the conditioned stimulus (CS) and intravenous injections of corticotropin-releasing hormone (CRH) (CRH group, N=17) or NaCl (placebo group, N=14) as the unconditioned stimulus (US) during two subsequent acquisition trials. Plasma levels of cortisol and noradrenaline, heart rate, and psychological parameters were analyzed before and 15, 30, 60, 120, and 180min after injection. The two acquisition trials were followed by two evocation trials, during which participants underwent the same procedure but now receiving NaCl injections. CRH administration induced pronounced increases in cortisol and noradrenaline plasma concentrations, heart rate, and anxiety levels. However, re-exposure to the CS during evocations trials did not provoke conditioned increases in neuroendocrine parameters. Median split of the CRH group based on the cortisol baseline level into "cort-high" and "cort-low" subgroups showed that the "cort-high" subgroup displayed a significantly increased cortisol production on evocation days compared to the "cort-low" subgroup and the placebo group. This taste-endocrine paradigm employing CRH injection as the US in healthy male volunteers failed to induce a behaviorally conditioned cortisol release as a learned endocrine response. Future studies should clarify a possible role of higher baseline cortisol levels in perhaps facilitating a conditioned cortisol response.

Regulation of Pulsatile and Entropic ACTH Secretion Under Fixed Exogenous Secretagogue Clamps.

Adrenocorticotropic hormone (ACTH) secretion is controlled by unobservable hypothalamic corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) pulses. Clamping exogenous CRH or AVP input could allow indirect quantification of the impact of the endogenous heterotypic hormone. We conducted a randomized, double-blind, placebo-controlled, crossover study in 28 healthy adults (16 men). Volunteers underwent a sex-steroid clamp and a cortisol clamp. ACTH was measured over 10 hours by 10-minute sampling during each of four randomized intravenous (IV) secretagogue clamps (i.e., continuous IV CRH, AVP, both peptides, or saline). Desensitization was tested by bolus injection of the noninfused peptide. Mean ± standard error of the mean 10-hour ACTH concentrations (ng/L) in the sex-combined analysis were: saline, 32 ± 4.6; AVP, 29 ± 4.6; CRH, 67 ± 6.2; and CRH-AVP, 67 ± 8.8 (any CRH vs AVP or saline, P < 0.0001). CRH and AVP increased approximate entropy (relative randomness) of ACTH release (P < 0.0001). Bolus AVP injection after CRH infusion yielded a 2.5-hour ACTH concentration of 46 ± 4.3, exceeding that seen after bolus CRH or saline injection (26 ± 3.3 and 24 ± 3.6, respectively; P = 0.002 and 0.001). Sex hormone clamps did not influence ACTH levels. A CRH, but not AVP, clamp yields sustained pulsatile ACTH secretion with high ACTH secretory-burst mass and randomness. After 10-hour CRH infusion, bolus AVP but not CRH, evoked marked ACTH release, likely caused by heterotypic sensitization of corticotropes by CRH. Similar interactions might underlie chronic stress states.

Corticotropin-releasing hormone induces depression-like changes of sleep electroencephalogram in healthy women

We reported previously that repetitive intravenous injections of corticotropin-releasing hormone (CRH) around sleep onset prompt depression-like changes in certain sleep and endocrine activity parameters (e.g. decrease of slow-wave sleep during the second half of the night, blunted growth hormone peak, elevated cortisol concentration during the first half of the night). Furthermore a sexual dimorphism of the sleep-endocrine effects of the hormones growth hormone-releasing hormone and ghrelin was observed. In the present placebo-controlled study we investigated the effect of pulsatile administration of 4×50μg CRH on sleep electroencephalogram (EEG) and nocturnal cortisol and GH concentration in young healthy women. After CRH compared to placebo, intermittent wakefulness increased during the total night and the sleep efficiency index decreased. During the first third of the night, REM sleep and stage 2 sleep increased and sleep stage 3 decreased. Cortisol concentration was elevated throughout the night and during the first and second third of the night. GH secretion remained unchanged. Our data suggest that after CRH some sleep and endocrine activity parameters show also depression-like changes in healthy women. These changes are more distinct in women than in men.

Abstract # 1797 Effects of corticotropin-releasing hormone on lymphocyte distribution and LPS-induced ex vivo cytokine production in humans: A pilot study

Corticotropin-releasing hormone (CRH) plays a major role in the activation of the hypothalamic–pituitary–adrenal axis and the sympathetic nervous system. However, the effects of peripheral CRH administration on immune functions are only partially known. In the present study, we used a clinically established CRH stimulation test to investigate potential CRH effects on blood immune cell distribution and ex vivo cytokine production in humans. Healthy male volunteers received an intravenous injection of either CRH (100 μ g, n = 7) or placebo (0.9% NaCl, n = 5) on two days with a 3-day washout phase in between. Blood samples, cardiovascular and psychological parameters were analyzed before (baseline) as well as 15, 30, 60, 120 and 180 min post injection. Results showed that CRH administration significantly increased cortisol and noradrenaline levels, heart rate, as well as self-reported side-effects and state anxiety. However, distribution of peripheral blood lymphocyte subsets and ex vivo lipopolysaccharide-stimulated production of IL-6 and TNF-alpha remained unaffected. Thus, even though peripheral administration of CRH induced pronounced neuroendocrine and psychological responses, it failed to affect lymphocyte circulation and cytokine release.

Differential Activation in Amygdala and Plasma Noradrenaline during Colorectal Distention by Administration of Corticotropin-Releasing Hormone between Healthy Individuals and Patients with Irritable Bowel Syndrome.

Irritable bowel syndrome (IBS) often comorbids mood and anxiety disorders. Corticotropin-releasing hormone (CRH) is a major mediator of the stress response in the brain-gut axis, but it is not clear how CRH agonists change human brain responses to interoceptive stimuli. We tested the hypothesis that brain activation in response to colorectal distention is enhanced after CRH injection in IBS patients compared to healthy controls. Brain H215O- positron emission tomography (PET) was performed in 16 male IBS patients and 16 age-matched male controls during baseline, no distention, mild and intense distention of the colorectum using barostat bag inflation. Either CRH (2 μg/kg) or saline (1:1) was then injected intravenously and the same distention protocol was repeated. Plasma adrenocorticotropic hormone (ACTH), serum cortisol and plasma noradrenaline levels were measured at each stimulation. At baseline, CRH without colorectal distention induced more activation in the right amygdala in IBS patients than in controls. During intense distention after CRH injection, controls showed significantly greater activation than IBS patients in the right amygdala. Plasma ACTH and serum cortisol secretion showed a significant interaction between drug (CRH, saline) and distention. Plasma noradrenaline at baseline significantly increased after CRH injection compared to before injection in IBS. Further, plasma noradrenaline showed a significant group (IBS, controls) by drug by distention interaction. Exogenous CRH differentially sensitizes brain regions of the emotional-arousal circuitry within the visceral pain matrix to colorectal distention and synergetic activation of noradrenergic function in IBS patients and healthy individuals.

Acute injections of corticosterone, norepinephrine and epinephrine retards food passage in the crop of chicks

The purpose of the present study was to clarify whether acute injection of stress-related hormones, corticosterone (CORT), norepinephrine (NE) and epinephrine (E) affect food passage in the crop of chicks (Gallus gallus). Subcutaneous (SQ) injection of CORT significantly retarded the food passage in the crop of chicks. Intraperitoneal (IP) injection of NE and E also significantly decreased the crop emptying rate. Additional experiments by using agonists of adrenergic receptors found that IP injection of phenylephrine and clonidine but not isoproterenol retarded the food passage in the crop of chicks. These results demonstrated that the effect of NE and E would be mediated by alpha-1-, alpha-2- rather than beta-adrenergic receptor. Finally, we found that injection of CORT, NE and E had no effect on the number of defecations while intracerebroventricular injection of corticotropin-releasing hormone and urocortin-3 significantly increased it. These results suggest that CORT, NE and E might affect the food passage in the upper digestive tract in chicks.

ACTH after 15 min distinguishes between Cushing's disease and ectopic Cushing's syndrome: a proposal for a short and simple CRH test.

The aim of the present study was to validate criteria of corticotropin-releasing hormone (CRH) stimulation and 8 mg dexamethasone suppression (high-dose dexamethasone suppression, HDDS) to distinguish the etiology of ACTH-dependent Cushing's syndrome. We retrospectively analyzed cortisol and ACTH after the injection of 100 μg human CRH in confirmed Cushing's disease (CD, n=78) and confirmed ectopic Cushing's syndrome (ECS, n=18). Cortisol and ACTH increase (in percentage above basal (%B)) at each time point, maximal increase (Δmax %B), and area under the curve (AUC %B) were analyzed using receiver operator characteristics (ROC) curve analyses. Cortisol suppression (%B) after 8 mg of dexamethasone was evaluated as a supplementary criterion. An increase in ACTH of ≥ 43%B at 15 min after CRH was the strongest predictor of CD, with a positive likelihood ratio of 14.0, a sensitivity of 83%, a specificity of 94%, a positive predictive value of 98% and a negative predictive value of 58%. All of the other criteria of stimulated ACTH and cortisol levels were not superior in predicting CD in response to CRH injection. The addition of cortisol suppression by dexamethasone did not increase the discriminatory power. However, the combination of a positive ACTH response at 15 min and a positive HDDS test excluded ECS in all cases. The present findings support the use of plasma ACTH levels 15 min after the injection of human CRH as a response criterion for distinguishing between CD and ECS. The addition of the HDDS test is helpful for excluding ECS when both tests are positive.

Su2045 Mast Cell CRF1 Mediates Mast Cell Degranulation and Intestinal Permeability in Response to Psychological and Immunological Stress

G A A b st ra ct s the effect of PHGG on stress mimicked corticotropin-releasing hormone (CRH) induced animal IBS model. Materials and methods. Six-week-old male Wistar rats were used in this study. Animals were allowed to acclimate to the environment for seven days before initiating the study. Under anesthesia, each rat was implanted stainless steel cannula placed towards the lateral cerebral ventricle. Then rats were divided into two groups of 8 animals each, (1) control group: diet without PHGG, (2) PHGG group: diet with 5% PHGG for seven days. After intracerebroventricular (icv) injection of CRH (10 μg / rat) or saline in each, the condition of stools was checked with a 2-hour fecal pellets output count. Three hours later, rats were sacrificed, and cecal contents were taken out to analyze the microbiota with terminal restriction fragment length polymorphism (T-RFLP). Results. The counts of stools were increased in CRH-treated animals compared to in saline-treated group animals with the control diet. However, in rats in PHGG group with icv of CRH, the numbers of stools were not increased. In PHGG group Clostridium subcluster XIVa, which thought to be products butyric acid and Bifidobacterium cluster were enlarged, but not in the control diet group, then after injection of CRH, Bifidobacterium cluster was decreased. Conclusions. PHGG improved CRH-induced bowel dysmotility and also modulated in the gut microbiota composition which were influenced by CRH administration. Our results indicate that braingut axis is deeply associated with gut microbiota in physiological mechanism in IBS. This study was supported by Japan Science and Technology Agency.

A putative corticosteroid hormone in Pacific lamprey, Entosphenus tridentatus

Great efforts have been put forth to elucidate the mechanisms of the stress response in vertebrates and demonstrate the conserved response across different vertebrate groups, ranging from similarities in the activation of the hypothalamic–pituitary–adrenal axis to the release and role of corticosteroids. There is however, still very little known about stress physiology in the Pacific lamprey (Entosphenus tridentatus), descendants of the earliest vertebrate lineage, the agnathans. In this paper we demonstrate that 11-deoxycortisol, a steroid precursor to cortisol in the steroidogenic pathway, may be a functional corticosteroid in Pacific lamprey. We identified the putative hormone in Pacific lamprey plasma by employing an array of methods such as RIA, HPLC and mass spectrometry analysis. We demonstrated that plasma levels of 11-deoxycortisol significantly increased in Pacific lamprey 0.5 and 1h after stress exposure and that lamprey corticotropin releasing hormone injections increased circulating levels of 11-deoxycortisol, suggesting that the stress response is under the control of the HPA/I axis as it is in higher vertebrates. A comprehensive understanding of vertebrate stress physiology may help shed light on the evolution of the corticosteroid signaling system within the vertebrate lineage.

Effects of aging on hypothalamic-pituitary-adrenal (HPA) axis activity and reactivity in virgin male and female California mice (Peromyscus californicus)

Life history theory posits that organisms face a trade-off between current and future reproductive attempts. The physiological mechanisms mediating such trade-offs are still largely unknown, but glucocorticoid hormones are likely candidates as elevated, post-stress glucocorticoid levels have been shown to suppress both reproductive physiology and reproductive behavior. Aged individuals have a decreasing window in which to reproduce, and are thus predicted to invest more heavily in current as opposed to future reproduction. Therefore, if glucocorticoids are important in mediating the trade-off between current and future reproduction, aged animals are expected to show decreased hypothalamic-pituitary-adrenal (HPA) axis responses to stressors and to stimulation by corticotropin-releasing hormone (CRH), and enhanced responses to glucocorticoid negative feedback, as compared to younger animals. We tested this hypothesis in the monogamous, biparental California mouse by comparing baseline and post-stress corticosterone levels, as well as corticosterone responses to dexamethasone (DEX) and CRH injections, between old (∼18–20months) and young (∼4months) virgin adults of both sexes. We also measured gonadal and uterine masses as a proxy for investment in potential current reproductive effort. Adrenal glands were weighed to determine if older animal had decreased adrenal mass. Old male mice had lower plasma corticosterone levels 8h after DEX injection than did young male mice, suggesting that the anterior pituitary of older males is more sensitive to DEX-induced negative feedback. Old female mice had higher body-mass-corrected uterine mass than did young females. No other differences in corticosterone levels or organ masses were found between age groups within either sex. In conclusion, we did not find strong evidence for age-related change in HPA activity or reactivity in virgin adult male or female California mice; however, future studies investigating HPA activity and reproductive outcomes in young and old breeding adults would be illuminating.

Dissociation between ACTH and cortisol response in DEX–CRH test in patients with panic disorder

Panic disorder (PD) has been associated with the altered circadian rhythm of the hypothalamic-pituitary-adrenocortical (HPA) axis. The findings regarding the stress-specific functioning of the HPA-system are inconsistent. It is also unclear whether the HPA-system response after the Corticotropin-Releasing-Hormone (CRH) challenge becomes altered. For this study, the dexamethasone-corticotropin-releasing-hormone (DEX-CRH) test was implemented to assess the HPA-axis reactivity indicated by the plasma adreno-corticotropin-hormone (ACTH) and the cortisol release. The sample included 32 patients diagnosed with PD in a Structured Clinical Interview (SCID). Fourteen male and eighteen female patients, [mean age = 33.50 years, SD = 12.76] were matched with 32 healthy controls by age and gender. Moreover, a sample of patients with unipolar depression (n = 21, ten females) was examined as a clinical control group. In healthy controls as well as in patients with PD and patients with unipolar depression, the ACTH and the cortisol response increased significantly due to the CRH injection after dexamethasone pre-treatment. There were differences between the healthy controls and the patients with PD in the plasma cortisol response pattern, however, not in the ACTH. The patients with PD showed a decreased CRH-induced plasma cortisol response. A median-split gave evidence that patients suffering from PD longer than two years showed a remarkably higher HPA-axis reactivity under CRH-injection than patients suffering from PD two years or less. These findings provide strong evidence that patients with PD show some dissociation between ACTH and cortisol response under the DEX-CRH test with strong indicators that the length of the duration of the psychopathology is a risk factor for an increased reactivity of the HPA-axis in patients with PD.

The Intestinal Microbiota Determines Mouse Behavior and Brain BDNF Levels

Aim: Corticotropin-releasing hormone (CRH) is a major mediator of stress response in the brain-gut axis. We previously reported that peptidergic modification of CRH receptors changes visceral sensorimotor function in patients with irritable bowel syndrome (IBS). However, evidence how CRH agonist changes human brain function was lacking. We hypothesized that exogenous CRH accelerates regional brain activity during visceral stimulation in human. Methods: Sixteen healthy males aged 22.8 +/2.5 were randomly allocated into the CRH injection group and saline injection (placebo) group. A barostat bag was inserted into the colorectum and was randomly inflated with sham (0 mmHg), mild (20mmHg), or intense (40 mmHg) distention for 90s. CRH (2μg/dl) or placebo was then injected and same distention protocol was repeated. Radioactive H2[O] saline was injected at bag inflation and then positron emission tomography was performed. Changes in regional cerebral blood flow were analyzed using statistical parametric mapping. Plasma adrenocorticotropic hormone (ACTH) and cortisol were measured at each stimulation. Results: Colorectal distention with 20 mmHg with CRH activated the right insula and parahippocampal gyrus significantly greater than that with placebo (p < 0.001). Colorectal distention with 40 mmHg with CRH activated the right dorsolateral prefrontal cortex, right orbitofrontal cortex, right insula, extended amygala, and pons significantly greater than that with placebo (p < 0.001). Twoway ANOVA of plasma ACTH showed significant CRH effect (p = 0.012), distention effect (p = 0.026) and CRH × distention interaction (p = 0.035). Post-hoc test of plasma ACTH revealed significantly higher level at 40mmHg with CRH than that with placebo (p = 0.011). Plasma cortisol showed similar pattern to plasma ACTH.Conclusion:During visceral stimulation in men, administration of CRH likely accelerates the activity of the brain regions which regulate interoception, hypothalamic regulation, stress coping, stress response, and negative emotion. These results also suggest that exogenous CRH may amplify ACTH and cortisol secretion due to colorectal distention.

Hemodynamic Actions of Corticotropin-Releasing Hormone and Proopiomelanocortin Derivatives in Septic Patients

Proopiomelanocortin (POMC) derivatives and mRNA of POMC have been detected in cardiomyocytes and vascular smooth muscle cells. Increased plasma levels of POMC derivatives have been found in septic patients during cardiovascular deregulation; therefore, we evaluated whether corticotroph-type (ACTH, β-endorphin, β-lipotropin) or melanotroph-type (α-melanocyte-stimulating hormone and N-acetyl-β-END) POMC derivatives have influences on patients' hemodynamics during sepsis. Seventeen septic patients were monitored by pulmonary artery catheter and corticotropin-releasing hormone (CRH) tests were performed by intravenous administration of 100 μg CRH. Before, 15, 30, 45, and 60 minutes after CRH administration, hemodynamic variables were measured, and plasma concentrations of POMC derivatives were determined. After CRH administration, heart rate, cardiac index, and stroke index increased, and the systemic vascular resistance index decreased; moreover, a correlation between ACTH concentration and stroke index as well as an inverse correlation between (α-melanocyte-stimulating hormone concentration and systemic vascular resistance index was observed. CRH and ACTH may have opposite effects on the blood pressure (mean arterial pressure). Immediately after CRH injection mean arterial pressure decreased. ACTH (in contrast to β-endorphin or β-lipotropin), released into the cardiovascular compartment 15 minutes after CRH injection, might have raised mean arterial pressure as compatible with the correlation between ACTH levels and stroke index. (α-melanocyte-stimulating hormone appears to have a vasodilative effect during sepsis.

Gonadotropin-releasing hormone II (GnRH II) mediates the anorexigenic actions of α-melanocyte-stimulating hormone (α-MSH) and corticotropin-releasing hormone (CRH) in goldfish

Intracerebroventricular (ICV) administration of gonadotropin-releasing hormone II (GnRH II), which plays a crucial role in the regulation of reproduction in vertebrates, markedly reduces food intake in goldfish. However, the neurochemical pathways involved in the anorexigenic action of GnRH II and its interaction with other neuropeptides have not yet been identified. Alpha-melanocyte-stimulating hormone (α-MSH), corticotropin-releasing hormone (CRH) and CRH-related peptides play a major role in feeding control as potent anorexigenic neuropeptides in goldfish. However, our previous study has indicated that the GnRH II-induced anorexigenic action is not blocked by treatment with melanocortin 4 receptor (MC4R) and CRH receptor antagonists. Therefore, in the present study, we further examined whether the anorexigenic effects of α-MSH and CRH in goldfish could be mediated through the GnRH receptor neuronal pathway. ICV injection of the MC4R agonist, melanotan II (80 pmol/g body weight; BW), significantly reduced food intake, and its anorexigenic effect was suppressed by ICV pre-administration of the GnRH type I receptor antagonist, antide (100 pmol/g BW). The CRH-induced (50 pmol/g BW) anorexigenic action was also blocked by treatment with antide. ICV injection of CRH (50 pmol/g BW) induced a significant increase of the GnRH II mRNA level in the hypothalamus, while ICV injection of melanotan II (80 pmol/g BW) had no effect on the level of GnRH II mRNA. These results indicate that, in goldfish, the anorexigenic actions of α-MSH and CRH are mediated through the GnRH type I receptor-signaling pathway, and that the GnRH II system regulates feeding behavior.