Adrenocorticotropic Hormone Suppression Research Articles

THU009 Subclinical Cushing’s Syndrome In An ACTH-secreting Pituitary Macroadenoma

Abstract Disclosure: N.G. Akabogu: None. D. Kumar: None. N. Sheung: None. A. Akofu: None. A. Uddin: None. S. Dejhansathit: None. F. Marium: None. L.G. Kurukulasuriya: None. Background: Subclinical Cushing’s syndrome (SCS) is characterized by subtle cortisol hypersecretion, which does not result in the typical signs and symptoms of Cushing’s syndrome (CS). While many of the signs and symptoms of CS are common in the general population, there are some that are discriminatory and specific for CS: supraclavicular fat pads, proximal muscle weakness, facial plethora, and violaceous striae. SCS manifests mostly as obesity, type 2 diabetes, and hypertension. Diagnosing SCS is challenging; however, the best screening test to uncover the subtle hypercortisolism is the dexamethasone suppression test (DST). Case presentation: We report a case of SCS in a 62 years old Caucasian postmenopausal patient with a medical history of total thyroidectomy for Graves’ disease, post-surgical hypothyroidism, 7.4cm right pheochromocytoma status post partial right adrenalectomy, incidentally discovered pituitary macroadenoma (during imaging to look for subarachnoid hemorrhage), untreated type 2 diabetes mellitus (A1c 6.6% and stable for 1 year before treatment), hypertension, atrial fibrillation, cerebrovascular accident, and worsening migraines. Patient’s physical exam was mostly unremarkable; she had central obesity and bilateral lower extremity swelling. Pituitary work-up showed evidence of secondary hypogonadism and secondary hypothyroidism with elevated adrenocorticotropic hormone (ACTH) of 130 (AM range: 7.2-63) and cortisol of 12.6, at 11:52AM. Further work-up for hypercortisolism revealed non-suppressed 8AM cortisol (5.83mcg/dL) on the low dose DST and 49% suppression of 8AM cortisol and ACTH on the high dose DST. 24hour urinary cortisol was normal. Patient did not perform the midnight salivary cortisol. Patient subsequently underwent trans-sphenoidal resection of the pituitary macroadenoma. Pathology analysis of the pituitary mass showed weak to moderate immunoreactivity for ACTH. Conclusion: Our patient had abnormal DST but normal 24hour urine cortisol. We may have missed her SCS if we screened her only with a 24hour urine cortisol. This confirms the fact that dexamethasone suppression test should be the first test in the evaluation of subclinical Cushing’s syndrome. Presentation: Thursday, June 15, 2023

Abstract #1413755: Subclinical Cushing’s Syndrome in an ACTH-secreting Pituitary Macroadenoma

Subclinical Cushing’s syndrome (SCS) is characterized by subtle cortisol hypersecretion, which does not result in the typical signs and symptoms of Cushing’s syndrome (CS). While many of the signs and symptoms of CS are common in the general population, there are some that are discriminatory and specific for CS: supraclavicular fat pads, proximal muscle weakness, facial plethora, and violaceous striae. SCS manifests mostly as obesity, type 2 diabetes, and hypertension. Diagnosing SCS is challenging; however, the best screening test to uncover the subtle hypercortisolism is the dexamethasone suppression test (DST). We report a case of SCS in a 62 years old Caucasian postmenopausal patient with a medical history of total thyroidectomy for Graves’ disease, post-surgical hypothyroidism, 7.4cm right pheochromocytoma status post partial right adrenalectomy, incidentally discovered pituitary macroadenoma (during imaging to look for subarachnoid hemorrhage), untreated type 2 diabetes mellitus (A1c 6.6% and stable for 1 year before treatment), hypertension, atrial fibrillation, cerebrovascular accident, and worsening migraines. Patient’s physical exam was mostly unremarkable; she had central obesity and bilateral lower extremity swelling. Pituitary work-up showed evidence of secondary hypogonadism and secondary hypothyroidism with elevated adrenocorticotropic hormone (ACTH) of 130 (AM range: 7.2-63) and cortisol of 12.6, at 11:52AM. Further work-up for hypercortisolism revealed non-suppressed cortisol (5.83mcg/dL) on the low dose DST and 49% suppression of cortisol and ACTH on the high dose DST. 24-hour urinary cortisol was normal. Patient did not perform the midnight salivary cortisol. Patient subsequently underwent trans-sphenoidal resection of the pituitary macroadenoma. Pathology analysis of the pituitary mass showed weak to moderate immunoreactivity for ACTH. Our patient had abnormal DST but normal 24hour urine cortisol. We may have missed her SCS if we screened her only with a 24hour urine cortisol. This confirms the fact that dexamethasone suppression test should be the first test in the evaluation of subclinical Cushing’s syndrome.

Tumor Shrinkage by Metyrapone in Cushing Disease Exhibiting Glucocorticoid-Induced Positive Feedback.

ContextParadoxical increases in serum cortisol in the dexamethasone suppression test (DST) have been rarely observed in Cushing disease (CD). Its pathophysiology and prevalence remain unclear.Case DescriptionA 62-year-old woman with suspected CD showed paradoxical increases in cortisol after both 1-mg and 8-mg DST (1.95-fold and 2.52-fold, respectively). The initiation of metyrapone paradoxically decreased plasma adrenocorticotropic hormone (ACTH) levels and suppressed cortisol levels. Moreover, the pituitary tumor considerably shrank during metyrapone treatment.Ex Vivo ExperimentsThe resected tumor tissue was enzymatically digested, dispersed, and embedded into Matrigel as 3D cultured cells. ACTH levels in the media were measured. In this tumor culture, ACTH levels increased 1.3-fold after dexamethasone treatment (P < 0.01) while control tumor cultures exhibited no increase in ACTH levels, but rather a 20% to 40% suppression (P < 0.05).Clinical StudyA cross-sectional, retrospective, multicenter study that included 92 patients with CD who underwent both low-dose and high-dose DST from 2014 to 2020 was performed. Eight cases (8.7%) showed an increase in serum cortisol after both low-dose and high-dose DST.ConclusionThis is the first report of a patient with glucocorticoid (GC)-driven positive feedback CD who showed both ACTH suppression and tumor shrinkage by metyrapone. Our cohort study revealed that 8.7% of patients with CD patients possibly possess GC-driven positive-feedback systems, thereby suggesting the presence of a new subtype of CD that is different from the majority of CD cases. The mechanisms exhibiting GC positive feedback in CD and the therapeutic approach for these patients remain to be investigated.

Glucocorticoids and the Brain after Critical Illness.

Treatment for critical illness typically focuses on a patient’s short-term physical recovery; however, recent work has broadened our understanding of the long-term implications of illness and treatment strategies. In particular, survivors of critical illness have significantly elevated risk of developing lasting cognitive impairment and psychiatric disorders. In this review, we examine the role of endogenous and exogenous glucocorticoids in neuropsychiatric outcomes following critical illness. Illness is marked by acute elevation of free cortisol and adrenocorticotropic hormone suppression, which typically normalize after recovery; however, prolonged dysregulation can sometimes occur. High glucocorticoid levels can cause lasting alterations to the plasticity and structural integrity of the hippocampus and prefrontal cortex, and this mechanism may plausibly contribute to impaired memory and cognition in critical illness survivors, though specific evidence is lacking. Glucocorticoids may also exacerbate inflammation-associated neural damage. Conversely, current evidence indicates that glucocorticoids during illness may protect against the development of post-traumatic stress disorder. We propose future directions for research in this field, including determining the role of persistent glucocorticoid elevations after illness in neuropsychiatric outcomes, the role of systemic vs neuroinflammation, and probing unexplored lines of investigation on the role of mineralocorticoid receptors and the gut–brain axis. Progress toward personalized medicine in this area has the potential to produce tangible improvements to the lives patients after a critical illness, including Coronavirus Disease 2019.

The value of serum dehydroepiandrosterone sulfate in differential diagnosis of Cushing's syndrome

Objective: To evaluate the changes and diagnostic value of serum dehydroepiandrosterone sulfate (DHEAS) in Cushing's syndrome (CS) with different etiologies. Methods: The study retrospectively recruited patients diagnosed as CS in Drum Tower Hospital affiliated to Nanjing University Medical School between January 2012 and June 2019, including 36 patients (8 males, 28 females, with an average age of 44 years) with Cushing disease (CD) and 64 patients (6 males, 58 females, with an average age of 39 years) with adrenal CS (ACS). Meanwhile, 97 patients diagnosed as nonfunctional adrenal adenoma (NFA) were also included as controls. Clinical characteristics, laboratory data, adrenocorticotropic hormone (ACTH), serum DHEAS level and sex-and age-adjusted DHEAS ratio of the three groups were collected. The sensitivity and specificity of DHEAS and its ratio in differential etiology diagnosis of CS were compared using receiver operating characteristic (ROC) curve analysis. Results: Compared to NFA group, ACS patients had lower DHEAS levels [0.39 (0.39, 0.63) μmol/L vs 2.96 (1.92, 4.60) μmol/L, P<0.01] and lower DHEAS ratio [0.58 (0.27, 0.98) vs 3.95 (3.08, 6.83), P<0.01]. DHEAS [6.49 (4.32, 11.63) μmol/L] and DHEAS ratio [9.17 (4.49, 15.41)] in CD patients were significantly higher compared to those in NFA and ACS patients (all P<0.01). There were 53 ACS patients (82.8%) with suppressed ACTH level (<2.2 pmol/L) and 11 patients (17.2%) with normal/high ACTH level (≥2.2 pmol/L). The level of 24 hour urine free cortisol in normal/high ACTH level group was lower than the suppressed ACTH group [(1 299±511) nmol/24 h vs (1 972±876) nmol/24 h, P=0.04]. No significant differences were found in the DHEAS and DHEAS ratio between the two groups. ROC analysis showed that the area under the curve of serum DHEAS and DHEAS ratio in diagnosing ACS from CD was 0.997 and 0.990, respectively. The optimal cut-off values for DHEAS and its ratio were 2.06 μmol/L and 2.10, respectively. The diagnostic sensitivity and specificity of DHEAS were 97.5% and 100%, and those of DHEAS ratio were 95.0% and 100%, respectively. Conclusion: There are significant differences in serum DHEAS level and DHEAS ratio between ACS and CD patients, which might be used as indicators for the identification of the two main CS etiologies, especially in the identification of ACS patients without plasma ACTH suppression from CD patients.

Hypothalamic-Pituitary-Adrenal Axis Recovery Following the 1-mg Overnight Dexamethasone Suppression Test in Healthy Volunteers.

BackgroundThe recovery of hypothalamic-pituitary-adrenal (HPA) axis suppression following pharmacological doses of various steroids has been studied previously. However, no study has been conducted using the more commonly used 1-mg dexamethasone in the overnight dexamethasone suppression test (ODST). Hence, we aimed at evaluating HPA axis recovery after the 1-mg ODST.ObjectivesThis study aimed at investigating the pattern and time of recovery of the HPA axis following the 1-mg ODST in healthy subjects.MethodsTen healthy volunteers aged 18 - 40 years, BMI < 30 kg/m2, with neither exposure to steroids nor interfering drugs were included. The 1-mg ODST was performed, and the adrenocorticotropic hormone (ACTH) and cortisol samples were withdrawn at regular intervals. The serum cortisol of < 1.8 µg/dL was considered as HPA axis suppression, whereas the cortisol value equal to or more than baseline was deemed as recovery.ResultsCortisol and ACTH levels were suppressed in all subjects 9 hours following the 1-mg ODST. Although ACTH showed an early increase after 8 hours, the upsurge was noticed following 24 hours (mean ± SD, 34.42 ± 18 pg/mL). Later, cortisol accompanied ACTH, and both reached their baseline after 72 hours (mean ± SD, ACTH, 37.48 ± 12.44 pg/mL; cortisol, 8.45 ± 3.32 μg/dL). A small dip in ACTH and cortisol (mean ACTH, 23.84 pg/mL; mean cortisol, 2.3 μg/dL) was observed after 24 - 36 hours indicating the return of the diurnal rhythm before complete recovery.ConclusionsThe complete recovery of the HPA axis occurs only 72 hours following the 1-mg ODST. ACTH begins to recover as early as 8 hours after the maximal suppression and diurnal rhythm of ACTH and cortisol resume 24 to 36 hours later.

Circulating interleukin-6 as a biomarker in a randomized controlled trial of modified-release prednisone vs immediate-release prednisolone, in newly diagnosed patients with giant cell arteritis.

To measure serial interleukin (IL)-6 levels in newly diagnosed patients with giant cell arteritis (GCA), treated in a randomized controlled trial of modified-release prednisone (MR) vs immediate-release prednisolone (IR) used in a tapering regimen conforming to British Society for Rheumatology GCA guidelines. Patients (n=12) were randomized into 2 treatment arms (7 MR, 5 IR) and followed over 26weeks. We measured IL-6 with additional markers. A significantly higher overall mean IL-6 level (P<.05) was seen in IR (mean=12.15, standard error [SE]=1.90) compared with MR (mean=4.39, SE=1.84). Mean collagen type 1 cross-linked C-telopeptide (CTX) concentration was significantly higher (P < .05) in both groups at week 4 (mean=0.29, SE=0.04) compared with week 26 (mean=0.13, SE=0.02). MR patients had adrenocorticotropic hormone (ACTH) suppression compared with IR (P<.05) throughout without differences in cortisol levels (P=.34). No significant differences were seen between arms in other markers. Our study suggests that elevated levels of IL-6 in new GCA are better suppressed by MR prednisone compared with IR prednisolone. CTX was significantly reduced in both treatment arms indicating early metabolic effect of glucocorticoids on bone. ACTH suppression with MR prednisone may reflect a greater impact on the hypothalamic-pituitary-adrenal axis although cortisol was not affected. MR prednisone warrants further investigation in GCA.

Value of fluorine-18-fluorodeoxyglucose PET/CT in localizing the primary lesion in adrenocorticotropic hormone-dependent Cushing syndrome.

This study aimed to present a proper understanding of the fluorine-18-fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) value in localizing the primary lesion in adrenocorticotropic hormone (ACTH)-dependent Cushing syndrome in a relatively large case cohort. This retrospective study included 47 patients with ACTH-dependent Cushing syndrome, who underwent an F-FDG PET/CT examination in our hospital from November 2010 to January 2018. The serum cortisol, 24 h urine cortisol, serum ACTH, and high-dose dexamethasone suppression test were measured in all the patients. Bilateral inferior petrosal sinus sampling was performed in 28/47 patients. Pituitary magnetic resonance imaging and whole-body F-FDG PET/CT were performed in all patients. Serum ACTH at 8 a.m. higher than 161.8 pg/ml as the cut-off value showed the best diagnostic accuracy (73.9%) for the successful localization of the primary lesions. In Cushing disease patients, the pituitary maximum standardized uptake value F-FDG PET/CT (n=11) did not show significant differences compared with that in ectopic ACTH syndrome (EAS) patients (n=20). In terms of EAS, the descending order of maximum standardized uptake value was 13.2±8.3 (4.8-26.4) in pancreatic neuroendocrine tumors (n=4), 7.1±2.4 (3.5-10.1) in mediastinal carcinoid (n=11), and 2.0±0.1 (1.9-2.2) in bronchial carcinoid (n=4). This study first reported the F-FDG PET/CT images of ACTH-secreting olfactory neuroblastoma. Serum ACTH level determines the success rate of localization of the primary ACTH-secreting tumor in ACTH-dependent syndrome. F-FDG PET/CT plays a role in localizing the site for EAS, although it plays a limited role in Cushing disease.

An early post-operative ACTH suppression test can safely predict short- and long-term remission after surgery of Cushing\u2019s disease

PurposeThe present study evaluates the usefulness of an ACTH suppression test shortly after surgery, and to determine optimal cut-off values of included laboratory analyses, in predicting short- and long-term remission after surgery of Cushing’s disease.MethodsA 48 h suppression test with betamethasone 2 mg/day applied after 45 transphenoidal adenomectomies in 28 patients was evaluated. Receiver operating characteristic (ROC)-curves were created for the included assays: plasma cortisol, plasma adrenocorticotropic hormone (ACTH) and urinary free cortisol (UFC). Plasma levels of cortisol and ACTH were measured both at 24 and 48 h. Youden’s index was used to determine cut-off with the highest sensitivity and specificity in predicting short- (3 months) and long-term (5 years or longer) remission. The area under curve (AUC) illustrated the clinical accuracy of the different assays.ResultsPlasma cortisol after 24 h with betamethasone was most accurate in predicting both short- and long-term remission. 3 months remission with cut-off 107 nmol/L: sensitivity 0.85, specificity 0.94, positive predictive value (PPV) 0.96 and AUC 0.92 (95% CI 0.85–1). 5 years remission with cut-off 49 nmol/L: sensitivity: 0.94, specificity 0.93, PPV 0.88, AUC 0.98 (95% CI 0.95–1). Analyses of ACTH or UFC did not improve diagnostic accuracy.ConclusionsA 48 h, 2 mg/day betamethasone suppression test after transphenoidal surgery of Cushing’s disease could predict short- and long-term remission with a high accuracy. Suppression of plasma cortisol after 24 h with betamethasone to values excluding Cushings disease in the diagnostic setting yielded the highest accuracy in predicting long-term remission.

New Insights in Cushing Disease Treatment With Focus on a Derivative of Vitamin A.

Cushing’s disease (CD) is an endocrine disorder originated by a corticotroph tumor. It is linked with high mortality and morbidity due to chronic hypercortisolism. Treatment goals are to control cortisol excess and achieve long-term remission, therefore, reducing both complications and patient’s mortality. First-line of treatment for CD is pituitary’s surgery. However, 30% of patients who undergo surgery experience recurrence in long-term follow-up. Persistent or recurrent CD demands second-line treatments, such as pituitary radiotherapy, adrenal surgery, and/or pharmacological therapy. The latter plays a key role in cortisol excess control. Its targets are inhibition of adrenocorticotropic hormone (ACTH) production, inhibition of adrenal steroidogenesis, or antagonism of cortisol action at its peripheral receptor. Retinoic acid (RA) is a metabolic product of vitamin A (retinol) and has been studied for its antiproliferative effects on corticotroph tumor cells. It has been shown that this drug regulates the expression of pro-opiomelanocortin (POMC), ACTH secretion, and tumor growth in corticotroph tumor mouse cell lines and in the nude mice experimental model, via inhibition of POMC transcription. It has been shown to result in tumor reduction, normalization of cortisol levels and clinical improvement in dogs treated with RA for 6 months. The orphan nuclear receptor COUP-TFI is expressed in normal corticotroph cells, but not in corticotroph tumoral cells, and inhibits RA pathways. A first clinical human study demonstrated clinical and biochemical effectiveness in 5/7 patients treated with RA for a period of up to 12 months. In a recent second clinical trial, 25% of 16 patients achieved eucortisolemia, and all achieved a cortisol reduction after 6- to 12-month treatment. The goal of this review is to discuss in the context of the available and future pharmacological treatments of CD, RA mechanisms of action on corticotroph tumor cells, and future perspectives, focusing on potential clinical implementation.

Social setting, social rank and HPA axis response in cynomolgus monkeys.

Hypothalamic-pituitary-adrenal (HPA) axis activity under different social settings in non-human primates is understudied. The aim of this study is to evaluate the response of pituitary-adrenal hormones (adrenocorticotropic hormone (ACTH) and cortisol) to pharmacological challenges of the HPA axis in male cynomolgus macaques under different social settings. Male cynomolgus macaques (Macaca fascicularis, n=11) were individually (A) and socially housed (B) in alternation, over consecutive months, in an ABA design. During each experimental phase, plasma ACTH and cortisol were measured in response to low- and mild-intensity psychological stressors and following administration of saline, naloxone, ovine-corticotropin-releasing factor (oCRF), and dexamethasone. These data demonstrate that cortisol measured under low stress conditions is sensitive to social rank (dominance hierarchy) and distinguishes dominant from non-dominant animals during both individual and social settings. Administration of naloxone resulted in elevated circulating ACTH and cortisol, while oCRF only increased circulating cortisol. During social housing, the cortisol response to naloxone and oCRF was increased, whereas dexamethasone suppression of ACTH and cortisol remained consistent across all social settings. Circulating ACTH and cortisol are differentially sensitive to changes in social settings in non-human primates. Cortisol response increased during social housing and could be stimulated by both naloxone and oCRF, whereas ACTH response was generally not influenced by social setting or oCRF but was increased by naloxone. These data show differential adrenal and pituitary response to changes in social settings and a small, but consistent, effect of social dominance.

Maternal flaxseed diet during lactation changes adrenal function in adult male rat offspring.

Flaxseed (Linum usitatissimum L.) has been a focus of interest in the field of functional foods because of its potential health benefits. However, we hypothesised that maternal flaxseed intake during lactation could induce several metabolic dysfunctions in adult offspring. In the present study, we aimed to characterise the adrenal function of adult offspring whose dams were supplemented with whole flaxseed during lactation. At birth, lactating Wistar rats were divided into two groups: rats from dams fed the flaxseed diet (FLAX) with 25% of flaxseed and controls dams. Pups received standard diet after weaning and male offspring were killed at age 180 days old to collect blood and tissues. We evaluated body weight and food intake during development, corticosteronaemia, adrenal catecholamine content, hepatic cholesterol, TAG and glycogen contents, and the protein expression of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), 11-β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) and adrenaline β2 receptor at postnatal day 180 (PN180). After weaning, pups from the FLAX group had a higher body weight (+10 %) and food intake (+10%). At PN180, the FLAX offspring exhibited higher serum corticosterone (+48%) and lower adrenal catecholamine ( - 23%) contents, lower glycogen ( - 30%), higher cholesterol (4-fold increase) and TAG (3-fold-increase) contents in the liver, and higher 11β-HSD1 (+62%) protein expression. Although the protein expression of hypothalamic CRH was unaffected, the FLAX offspring had lower protein expression of pituitary ACTH ( - 34%). Therefore, induction of hypercorticosteronaemia by dietary flaxseed during lactation may be due to an increased hepatic activation of 11β-HSD1 and suppression of ACTH. The changes in the liver fat content of the FLAX group are suggestive of steatosis, in which hypercorticosteronaemia may play an important role. Thus, it is recommended that lactating women restrict the intake of flaxseed during lactation.

Genetic load is associated with hypothalamic–pituitary–adrenal axis dysregulation in macaques

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis pathway is associated with several neuropsychiatric disorders, including post-traumatic stress disorder (PTSD), major depressive disorder (MDD), schizophrenia and alcohol abuse. Studies have demonstrated an association between HPA axis dysfunction and gene variants within the cortisol, serotonin and opioid signaling pathways. We characterized polymorphisms in genes linked to these three neurotransmitter pathways and tested their potential interactions with HPA axis activity, as measured by dexamethasone (DEX) suppression response. We determined the percent DEX suppression of adrenocorticotropic hormone (ACTH) and cortisol in 62 unrelated, male rhesus macaques. While DEX suppression of cortisol was robust amongst 87% of the subjects, ACTH suppression levels were broadly distributed from -21% to 66%. Thirty-seven monkeys from the high and low ends of the ACTH suppression distribution (18 'high' and 19 'low' animals) were genotyped at selected polymorphisms in five unlinked genes (rhCRH, rhTPH2, rhMAOA, rhSLC6A4 and rhOPRM). Associations were identified between three variants (rhCRH-2610C>T, rhTPH2 2051A>C and rh5-HTTLPR) and level of DEX suppression of ACTH. In addition, a significant additive effect of the 'risk' genotypes from these three loci was detected, with an increasing number of 'risk' genotypes associated with a blunted ACTH response (P = 0.0009). These findings suggest that assessment of multiple risk alleles in serotonin and cortisol signaling pathway genes may better predict risk for HPA axis dysregulation and associated psychiatric disorders than the evaluation of single gene variants alone.

The impact of water-floating and high-intensity exercise on rat’s HPA axis and interleukins concentrations

Our studies explore the changes of blood corticosterone (CORT), adrenocorticotropic hormone (ACTH), interleukin (IL)-1β, IL-2, IL-6 concentrations and the pituitary ACTH expression in rats after water floating in the presence or absence of following high-intensity exercise. The rats were randomly assigned into three groups. Group A served as control; Group B received 180 minutes water floating and psychological (fear) stimulation; Group C received the same treatment as Group B in addition and 120-minutes non-stop running. Compared to Group A, Group B showed a significant increase of IL-2 (19.91 ± 2.52 vs. 13.09 ± 3.13 ng/ml, P < 0.05), and IL-6 (0.18 ± 0.08 vs. 0.12 ± 0.05 ng/ml, P < 0.05); Group C demonstrated a significant increase of CORT (977.22 ± 207.36 ng/ml vs. 434.58 ± 110.45 ng/ml, P <0.01) and IL-1β (0.21 ± 0.04 vs. 0.16 ± 0.06 ng/ml, P < 0.05), IL-2 (20.29 ± 4.23 vs. 13.09 ± 3.13 ng/ml, P < 0.05), and IL-6 (0.19 ± 0.03 vs. 0.12 ± 0.05 ng/ml, P < 0.05) levels, and a significant decrease of ACTH (16.95 ± 5.46 vs. 22.96 ± 7.32 pg/ml, P = 0.03). Immunohistochemical staining showed the decreased number of pituitary ACTH-positive cells in both Groups B and C (P < 0.05) as compared to Group A. These results have lead us to believe that acute psychological stress can activate the pituitary-adrenal axis and lead to elevation of serum IL-2, IL-6 concentrations. Combined with high-intensity exercise, it can result in the increase of serum CORT, IL-1β, IL-2, IL-6 levels, and the suppression of ACTH.

Cortisol-Induced Increases of Plasma Oxytocin Levels Predict Decreased Immediate Free Recall of Unpleasant Words

Cortisol and oxytocin have been shown to interact in both the regulation of stress responses and in memory function. In the present study we administered cortisol to 35 healthy female subjects in a within-subject double-blind placebo-controlled design, while measuring oxytocin levels, adrenocorticotropic hormone (ACTH) levels, and free recall of pleasant and of unpleasant words. We found that cortisol administration suppressed ACTH levels and (1) induced a decrease in oxytocin associated with ACTH suppression and (2) an increase in oxytocin that was independent from ACTH suppression. This cortisol-induced increase in plasma oxytocin was associated with a selective decrease in immediate free recall of unpleasant words from primacy positions. The present results add to evidence that cortisol-induced increases in oxytocin could mediate some of the effects of stress and cortisol on memory, and possibly play a role in the regulation of the hypothalamo-pituitary–adrenal stress response. This mechanism could significantly impact affective and social behaviors, in particular during times of stress.

Medical suppression of hypercortisolemia in Cushing’s syndrome with particular consideration of etomidate

Cushing's syndrome is associated with excessive cortisol secretion by the adrenal gland or ectopic tumours and may result in diabetes, hypertension, and life-threatening infections with high mortality rates especially in the case of surgical resection. Although surgical resection is the treatment of choice, patients may benefit from preceding medical therapy. This may especially be useful as an adjunctive approach in emergency settings, if patients cannot undergo surgery, if surgery or radiotherapy fails, or if the tumour recurs. Medical therapy can be categorized in three different groups-inhibition of steroidogenesis, suppression of adrenocorticotropic hormone, and antagonism of the glucocorticoid receptor. However, the majority of common drugs are not available for parenteral administration, which may evoke a management problem in emergency settings or in patients unable to tolerate oral medication. The carboxylated imidazole etomidate is a well known parenteral induction agent for general anaesthesia. Besides its hypnotic properties, etomidate also has α-adrenergic characteristics and inhibits the enzyme 11-deoxycortisol ß-hydroxylase, which catalyzes the final step of the conversion of cholesterol to cortisol. Adverse outcomes have been reported when used for sedation in septic or trauma patients probably by its interference with steroid homeostasis. However, its capability of inhibition of the 11-deoxycortisol ß-hydroxylase leads to suppression of cortisol secretion which has been demonstrated to be a useful tool in severe and complicated hypercortisolemia. Within this article, we review the data concerning different pharmacological approaches with particular consideration of etomidate in order to suppress steroidogenesis in patients with Cushing's syndrome.

Heightening of the stress response during the first weeks after a mild traumatic brain injury

The effects of a mild traumatic brain injury range from white matter disruption to affective disorders. We set out to determine the response to restraint-induced stress after a mild fluid-percussion injury (FPI), an experimental model for brain injury. Hypothalamic-pituitary-adrenal (HPA) axis regulation of corticosterone (CORT) and adrenocorticotropic hormone (ACTH) was determined during the first post-injury weeks, which corresponds to the same time period when rehabilitative exercise has been shown to be ineffective after a mild FPI. Adult male rats underwent either an FPI or sham injury. Additional rats were only exposed to anesthesia. HPA regulation was evaluated by measuring the effects of dexamethasone (DEX) treatment on CORT and ACTH. Tail vein blood was collected following 30-min restraint stress, at post-injury days (PID) 1, 7 and 14, prior to (0 min) and at 30, 60, 90 and 120 min after stress onset. Results from these studies indicate that the stress response was significantly more pronounced after FPI in that CORT and ACTH restraint-induced increases were more pronounced and longer lasting compared to controls. DEX suppression of CORT and ACTH was observed in all groups, suggesting that stress hyper-responsiveness after mild FPI is not attributable to reduced sensitivity of CORT feedback regulation. The increased sensitivity to stressful events in the first two post-injury weeks after a mild FPI may have a negative impact on early rehabilitative therapies.

Rapid alteration of stress-induced hypothalamic–pituitary–adrenal hormone secretion in the rat: A comparison of glucocorticoids and cannabinoids

The hypothalamic–pituitary–adrenal (HPA) axis self-regulates through a glucocorticoid negative feedback mechanism that is stereotypically slow and long lasting. Rapid (seconds to minutes) glucocorticoid feedback, however, inhibits stress-induced adrenocorticotropic hormone (ACTH) secretion too quickly to result from classic transcriptional effects of the occupied glucocorticoid receptor. Cannabinoids may act as rapid intermediary messengers between glucocorticoids and HPA activation via retroactive inhibition of afferent glutamate stimulation of the corticotropin-releasing factor neurons in the paraventricular nucleus. We demonstrated fast feedback effects of GR stimulation and blockade and observed the effect of cannabinoid receptor (CB1) antagonist AM251 on HPA axis reactivity in vivo. Rats were injected intraperitoneally with varying doses of the specific GR agonist RU28362, the GR antagonist RU486, or AM251 2 min before restraint. Blood was collected at predetermined times and corticosterone and ACTH concentrations were measured. RU28362 blunted stress-induced ACTH secretion while RU486 and AM251 significantly increased stress-induced ACTH release 15 min after restraint onset. Next, we injected AM251 58 min before RU28362, 2 min before restraint, to determine if inhibition of ACTH by RU28362 was contingent on CB1 activation. Unexpectedly, CB1 blockade failed to prevent glucocorticoid negative feedback and instead enhanced it. These studies not only establish an in vivo fast feedback model but show that rapid glucococorticoid negative feedback is similarly altered by GR and CB1 blockade. Although the hormonal consequences of acute AM251 treatment were strikingly similar to those of RU486 treatment, we are unable to draw conclusions about the serial nature of the interaction between GR activation and CB release from these results.

The Dexamethasone Suppression Test and Long-Term Contraceptive Treatment: Measurement of ACTH or Salivary Cortisol Does Not Improve the Reliability of the Test

Under the influence of high estrogen levels, the suppression of total serum cortisol in the dexamethasone test has often been found to be incomplete. Its measurement for the purpose of excluding Cushing's disease or adrenal tumors in women taking oral contraceptives is, therefore, considered unreliable. This study was designed to compare the reliability of measurements of total cortisol, unbound cortisol and ACTH suppression during chronic hyperestrogenaemia. An overnight suppression test with 2 mg of dexamethasone was performed in 19 women receiving long-term contraceptive treatment (group A) and in 12 controls (group C). Baseline and post-dexamethasone morning levels of ACTH, total serum cortisol and unbound salivary cortisol were determined by RIA. In addition, unbound serum cortisol was measured by equilibrium dialysis. Mean baseline levels of all four parameters were significantly higher in group A. This result points towards the possibility of a direct stimulatory effect of estrogens upon the corticotroph axis which is independent from CBG-mediated increase of total cortisol. Post-dexamethasone values of total and unbound cortisol showed no statistically significant differences, while ACTH suppression in group A was even slightly better than in group C. From these data it is concluded that there is no need for post-dexa routine measurement of ACTH or unbound cortisol under contraceptive treatment since neither one of these parameters provides any additional information in comparison to total cortisol.

Circadian cortisol secretion and circadian adrenal responses to ACTH are maintained in dexamethasone suppressed capuchin monkeys (Cebus apella)

We tested the hypothesis that the capuchin monkey adrenal (Cebus apella) gland has oscillatory properties that are independent of adrenocorticotropic hormone (ACTH) by exploring under ACTH suppression by dexamethasone: (i) maintenance of a circadian rhythm of plasma cortisol and (ii) clock time dependency of plasma cortisol response to exogenous ACTH. The capuchin monkey had a clear ACTH and plasma cortisol rhythm. Dexamethasone treatment resulted in low non-rhythmic ACTH levels and decreased cortisol to 1/10 of control values; nevertheless, the circadian rhythm of plasma cortisol persisted. We found that cortisol response to exogenous ACTH was clock time-dependent. The maximal response to ACTH occurred at the acrophase of the cortisol rhythm (0800 h). These results suggest that the capuchin monkey adrenal cortex may possess intrinsic oscillatory properties that participate in the circadian rhythm of adrenal cortisol secretion and in the circadian cortisol response to ACTH.