Increased Plasma ACTH Research Articles

Pro-opiomelanocortin and ACTH-cortisol dissociation during pediatric cardiac surgery.

In critically ill adults, high plasma cortisol in face of low ACTH coincides with high pro-opiomelanocortin (POMC) levels. Glucocorticoids further lower ACTH without affecting POMC. We hypothesized that in pediatric cardiac surgery-induced critical illness, plasma POMC is elevated, plasma ACTH transiently rises intraoperatively but becomes suppressed post-operatively, and glucocorticoid administration amplifies this phenotype. From 53 patients (0-36 months), plasma was obtained pre-operatively, intraoperatively and on post-operative day 1 and 2. Plasma was also collected from 24 healthy children. In patients, POMC was supra-normal pre-operatively (p<0.0001) but no longer thereafter (p<0.05). ACTH was never high in patients. While in glucocorticoid-naive patients ACTH became suppressed by post-operative day 1 (p<0.0001), glucocorticoid-treated patients had suppressed ACTH already intraoperatively (p≤0.0001). Pre-operatively high POMC, not accompanied by increased plasma ACTH, suggests a centrally-activated HPA-axis with reduced pituitary processing of POMC into ACTH. Increasing systemic glucocorticoid availability with glucocorticoid treatment accelerated the suppression of plasma ACTH.

Exposure to low-intensity noise exacerbates nonalcoholic fatty liver disease by activating hypothalamus pituitary adrenal axis

Noise exposure induces metabolic disorders, in a latent, chronic and complex way. However, there is no direct evidence elucidating the relationship between low-intensity noise exposure and nonalcoholic fatty liver disease (NAFLD). Male mice (n = 5) on high-fat diet (HFD) were exposed to an average of 75 dB SPL noise for 3 months to reveal the effect of noise exposure on NAFLD, where the potential mechanisms were explored. In vivo (n = 5) and in vitro models challenged with dexamethasone (DEX) were used to verify the role of hypothalamus pituitary adrenal (HPA) axis activation in hepatic lipid metabolism. Typical chronic-restraint stress (CRS, n = 8) was used to explore the role of depression in modifying activity of HPA axis. Finally, animal experiment (n = 8) was repeated to validate the roles of depression and HPA axis activation in NAFLD development. Chronic low-intensity noise exposure exacerbated NAFLD in mice on HFD characterized by hepatocyte steatosis, modified lipid metabolism and inflammation level. Plasma ACTH in H + N group was 1.5-fold higher than that in HFD group. Transcription of glucocorticoid receptor target genes was increased by chronic low-intensity noise exposure in HFD-treated mice. Excessive glucocorticoids mimicking HPA axis activation induced NAFLD in vivo and in vitro. Plasma ACTH increase and lipid storage also occurred in depressive mice stressed by CRS. More interestingly, the same noise exposure simultaneously induced depression in mice, disrupted the HPA axis homeostasis and exacerbated NAFLD in a repeated experiment. Thus, three-month exposure to 75 dB SPL noise was sufficient to exacerbate NAFLD progress in mice, where activation of HPA axis played a critical role. Depression played an intermediate role and contributed to HPA axis activation up-stream of the exacerbation.

Maternal separation and TNBS-induced gut inflammation synergistically alter the sexually differentiated stress response in rats

BackgroundNeonatal maternal separation (MS) has been used to model long-lasting changes in behavior caused by neuroplastic changes associated with exposure to early-life stress. Earlier studies showed that transient gut inflammation can influence the development of irritable bowel syndrome (IBS). A prevailing paradigm of the etiology of IBS is that transient noxious events lead to long-lasting sensitization of the neural pain circuit, despite complete resolution of the initiating event. This study characterizes the changes in behaviors and neuroendocrine parameters after MS and early-phase trinitrobenzene sulfonic acid (TNBS)-induced colitis. We tested the hypothesis that MS and gut inflammation synergistically induce (1) hyperactivity in male rats and anxiety-like behaviors in female rats and (2) activation of the HPA axis in female rats and deactivation of the HPA axis in male rats after colorectal distention (CRD).MethodsMale and female rat pups were separated from their dams for 180 min daily from postnatal day (PND) 2 to PND 14 (MS). Early-phase colitis was induced by colorectal administration with TNBS on PND 8. The elevated plus-maze test was performed at 7 weeks. Tonic CRD was performed at 60 mmHg for 15 min at 8 weeks. Plasma ACTH and serum corticosterone were measured at baseline or after the CRD. Analysis of variance was performed for comparison among controls, TNBS, MS, and MS + TNBS.ResultsIn male rats, the time spent in open arms significantly differed among the groups (p < 0.005). The time spent in open arms in male MS + TNBS rats was significantly higher than that of controls (p < 0.009) or TNBS rats (p < 0.031, post hoc test). Female rats showed no difference in the time spent in open arms among the groups. MS and gut inflammation induced an increase in plasma ACTH in female rats but not in male rats at baseline.ConclusionsThese findings suggest that MS and gut inflammation synergistically induce hyperactive behavior or exaggerated hypothalamic–pituitary–adrenal axis function depending on sex.

Sleep restriction during opioid abstinence affects the hypothalamic-pituitary-adrenal (HPA) axis in male and female rats

Hypothalamic-pituitary-adrenal (HPA) axis dynamics are disrupted by opioids and may be involved in substance abuse; this persists during withdrawal and abstinence and is associated with co-morbid sleep disruption leading to vulnerability to relapse. We hypothesized that chronic sleep restriction (SR) alters the HPA axis diurnal rhythm and the sexually dimorphic response to acute stressor during opioid abstinence. We developed a rat model to evaluate the effect of persistent sleep loss during opioid abstinence on HPA axis dynamics in male and female rats. Plasma ACTH and corticosterone were measured diurnally and in response to acute restraint stress in rats Before (control) compared to During subsequent opioid abstinence without or with SR. Abstinence, regardless of sleep state, led to an increase in plasma ACTH and corticosterone in the morning in males. There was a tendency for higher PM plasma ACTH during abstinence in SR males (p = 0.076). ACTH and corticosterone responses to restraint were reduced in male SR rats whereas there was a failure to achieve the post-restraint nadir in female SR rats. There was no effect of the treatments or interventions on adrenal weight normalized to body weight. SR resulted in a dramatic increase in hypothalamic PVN AVP mRNA and plasma copeptin in male but not female rats. This corresponded to the attenuation of the HPA axis stress response in SR males during opioid abstinence. We have identified a potentially unique, sexually dimorphic role for magnocellular vasopressin in the control of the HPA axis during opioid abstinence and sleep restriction.

A Long-Acting Neutralizing Monoclonal ACTH Antibody Blocks Corticosterone and Adrenal Gene Responses in Neonatal Rats.

The control of steroidogenesis in the neonatal adrenal gland is of great clinical interest. We have previously demonstrated that the postnatal day (PD) 2 rat exhibits a large plasma corticosterone response to hypoxia in the absence of an increase in plasma ACTH measured by RIA, whereas the corticosterone response to exogenous ACTH is intact. By PD8, the corticosterone response to hypoxia is clearly ACTH-dependent. We hypothesized that this apparently ACTH-independent response to hypoxia in the newborn rat is due to an increase in a bioactive, nonimmunoassayable form of ACTH. To evaluate this phenomenon, we pretreated neonatal rats with a novel, specific, neutralizing anti-ACTH antibody (ALD1611) (20 mg/kg or 1 mg/kg IP) on the morning of PD1, PD7, and PD14. Twenty-four hours later, we measured hypoxia- or ACTH-stimulated plasma ACTH and corticosterone. For long-term effects, ALD1611 was given on PD1 and pups were studied on PD8 and PD15. Pretreatment with ALD1611 significantly decreased baseline corticosterone and completely blocked the corticosterone response to hypoxia and exogenous ACTH stimulation at all ages. The effect of 1 mg/kg ALD1611 on PD1 had dissipated by PD15. The decrease in corticosterone in ALD1611-treated pups was associated with decreases in baseline and hypoxia- and ACTH-stimulated adrenal Ldlr, Mrap, and Star mRNA expression at all ages. The adrenal response to hypoxia in the newborn rat is ACTH-dependent, suggesting the release of nonimmunoassayable, biologically active forms of ACTH. ALD1611 is useful as a tool to attenuate stress-induced, ACTH-dependent adrenal steroidogenesis in vivo.

SUN-400 Assay-Specific Spurious ACTH Results Lead to Misdiagnosis, Unnecessary Testing, and Surgical Misadventure: A Case Series

The reliable measurement of plasma ACTH is essential for the accurate diagnosis and differential diagnosis of Cushing’s syndrome (CS). We report 5 women with the misdiagnosis or incorrect differential diagnosis of CS due to spurious results from an ACTH assay (method I). Plasma ACTH (pg/mL), measured by other methods (C and A), provided accurate results. Case 1: 22-year-old (yo): Basal (203) and post oDST (83) ACTH(I) were elevated; however, AM serum cortisol, late-night salivary cortisol (LNSC), and post 1 mg overnight dexamethasone suppression test (oDST) cortisol were all normal. ACTH-dependent CS was suspected. MRI suggested a pituitary microadenoma; IPSS ACTH(I) showed a significant pituitary ACTH gradient. Pituitary surgery found a possible microadenoma (ACTH-negative). 3 months post-op, ACTH(I) was 57; heterophile Abs were negative. Repeat testing with ACTH(C) was 28. Final diagnosis: CS was ruled out; symptoms attributed to Lyme disease.Case 2: 31 yo: ACTH(I) (62), UFC, LNSC, and oDST cortisol were elevated. MRI found a pituitary microadenoma; IPSS found no gradient. Systemic imaging was negative other than a unilateral adrenal neoplasm. Occult ectopic ACTH-dependent CS was suspected. On metyrapone, ACTH(I) was 45; ACTH(C) was 2.4. A benign adrenal adenoma was removed followed by secondary adrenal insufficiency (AI). Final diagnosis: ACTH-independent (adrenal) CS, in remission.Case 3: 58 yo: CT found a 2 cm R adrenal nodule. ACTH(I) (41-143), serum cortisol, UFC, and oDST cortisol were elevated. MRI showed a possible 3 mm pituitary lesion. IPSS by ACTH(I) found no gradient. Occult ectopic ACTH-dependent CS was suspected. ACTH(C) was 3.3; serum cortisol and LNSC were normal. A benign adrenal adenoma was removed followed by secondary AI. Final diagnosis: ACTH-independent (adrenal) CS, in remission.Case 4: 59 yo: ACTH(I) was 367-1031. Referred for IPSS. Ectopic ACTH was suspected. However, ACTH(C) was 7.3; serum cortisol and DHEA were normal. LNSC was elevated. Patient had a history of alcohol abuse. After alcohol was stopped, LNSC normalized. Final diagnosis: alcohol-induced ACTH-dependent hypercortisolism. Case 5: 23 yo referred for IPSS with elevations of UFC, LNSC, and post-oDST cortisol. ACTH(I) was 22. ACTH-dependent CS was suspected. Basal ACTH(C) was 1.0 without an increase after CRH. CT showed a 3 cm R adrenal nodule. Adenoma removed followed by secondary AI. Final diagnosis: ACTH-independent (adrenal) CS, in remission.College of American Pathologists Proficiency Testing sample TMB-05-2016 found a very high ACTH(I)(103) whereas ACTH(C) and ACTH(A) were 2.4. Conclusion: ACTH(I) may provide misleading elevations of ACTH and cause an incorrect diagnosis or etiology of CS. When confronted with incongruously increased plasma ACTH results, clinicians should inquire as to the method used and request reanalysis of the sample using an alternate method.

PREOPERATIVE TREATMENT WITH METYRAPONE IN PATIENTS WITH CUSHING'S SYNDROME DUE TO ADRENAL ADENOMA.

ObjectiveMetyrapone has been approved for the treatment of patients with Cushing’s syndrome (CS), but only few retrospective clinical studies are available. The aim of our study was the prospective assessment of metyrapone as pre-operative treatment.Design and methodsBefore adrenalectomy, seven patients with ACTH-independent CS due to adrenal adenoma were prospectively treated with metyrapone for 3 months in three tertiary academic centers, with endocrine work-up and clinical evaluation at screening and at predefined evaluation time points (Days 14, 31, 48, 65, 82).ResultsIn all patients, UFC levels decreased up to normal range from baseline to Day 82 (609 (188–1476) vs 69 (28–152) nmol/24 h, P < 0.02), with a reduction of serum and salivary cortisol levels, and no significant increase of plasma ACTH and serum DHEAS levels. Clinical improvement was reported on quality of life (+16.7 (+4.2; +52.00) points, P < 0.04) and pressure control (systolic pressure, −25 (−52; −10) mmHg, P < 0.01; diastolic pressure, −16 (−50; +2 mmHg), P < 0.03). No significant change in weight, electrolytes, glycemic and lipid profile was reported. Although in women a significant increase of testosterone and androstenedione was reported, no worsening of clinical hyperandrogenism was observed. All drug-related adverse events (nausea, fatigue, low grade fever, edema of lower limbs and facial rash) were grade 1 or 2 and generally transient.ConclusionsThis prospective pilot study demonstrated that metyrapone is effective in normalizing biochemical and clinical parameters in patients with CS due to adrenal adenoma before surgical intervention, with minimal side effects.

CYP11A1 inhibition as a therapeutic approach for the treatment of castration resistant prostate cancer.

340 Background: Castration-resistant prostate cancer (CRPC) is a major cause of cancer mortality worldwide. The mechanisms behind the development of resistance are complex and not fully understood; altered androgen synthesis, androgen receptor (AR) overexpression or gene amplification, and mutations have been indentified. However, tumor growth may still be responsive to therapies that can further suppress de novo intratumoral steroid synthesis upstream of CYP17A1. ODM-208 is an oral, non-steroidal and selective inhibitor of CYP11A1 enzyme that suppresses the synthesis of all steroid hormones and their precursors. Methods: The inhibition of CYP11A1 was measured in vitro by the formation of radiolabelled isocapronic acid in a human adrenal cortex cell line (H295R), and further analysing pregnenolone (Preg) and testosterone (T) formation by ELISA. The tumor growth inhibition of ODM-208 alone or in combination with prednisone (Pred) was studied in VCaP CRPC xenograft where also concentrations of main steroid hormones progesterone (P), corticosterone (CORT) and T in tumors and adrenals were analysed. In addition, plasma ACTH and LH levels were measured at the end of the xenograft study. In dogs an ACTH stimulation test was done. Toxicity studies were conducted in rats and dogs. Results: ODM-208 potently inhibits CYP11A1 and synthesis of Preg and T with nM concentrations in vitro. In the VCaP CRPC xenograft ODM-208 alone and in combination with Pred significantly inhibited tumor growth. Concentrations of T, P and CORT were significantly decreased in the adrenals, indicating strong CYP11A1 inhibition. Also, significantly decreased steroid levels in tumors was observedhe Pred combination increased plasma ACTH levels less than ODM-208 alone, whereas no difference was seen in the LH. In dogs ACTH-stimulated cortisol production was significantly inhibited after single oral dose of ODM-208. In toxicological studies ODM-208 showed expected reversible findings in target tissues, mainly related to the pharmacology. Conclusions: ODM-208 shows promising antitumor activity in preclinical CRPC models with favorable toxicological profile. Thus, ODM-208 might have potential for treating the patients with CRPC.

Effects on Hedonic Feeding, Energy Expenditure and Balance of the Non-opioid Peptide DYN-A2-17

The dynorphin (DYN) peptide family includes opioid and non-opioid peptides, yet the physiological role of the non-opioid DYN peptides remains poorly understood. Recent evidence shows that administering the non-opioid peptide DYN-A2-17 into the paraventricular hypothalamic nucleus (PVN) simultaneously increased short-term intake of standard rodent chow and spontaneous physical activity (SPA). The present studies aimed to expand upon the mechanisms and role of DYN-A2-17 on food intake and energy expenditure. Injection of DYN-A2-17 in PVN increased SPA, energy expenditure and wheel running in the absence of food. Repeated DYN-A2-17 injection in PVN increased short-term chow intake, but this effect habituated over time and failed to alter cumulative food intake, body weight or adiposity. Pre-treatment with a CRF receptor antagonist into PVN blocked the effects of DYN-A2-17 on food intake while injection of DYN-A2-17 in PVN increased plasma ACTH. Finally, as DYN peptides are co-released with orexin peptides, we compared the effects of DYN-A2-17 to orexin-A and the opioid peptide DYN-A1-13 on food choice and intake in PVN when palatable snacks and chow were available. DYN-A1-13 selectively increased intake of palatable snacks. DYN-A2-17 and orexin-A decreased palatable snack intake while orexin-A also increased chow intake. These findings demonstrate that the non-opioid peptide DYN-A2-17 acutely regulates physical activity, energy expenditure and food intake without long-term effects on energy balance. These data also propose different roles of opioid, non-opioid DYN and orexin peptides on food choice and intake when palatable and non-palatable food options are available.

Chronic social isolation in adaptation of HPA axis to heterotypic stress.

Social crowding and isolation are recognized as major stressors and risk factors for development of psychiatric disorders. Chronic isolation stress (IS) and crowding stress (CS) activate neuroendocrine and neurochemical mechanisms, that activate the hypothalamic-pituitary-adrenal (HPA) axis. Changes of the plasma level of interleukin-1β (IL-1β), ACTH and corticosterone (CORT) after chronic psychosocial IS and CS were investigated. Control rats were kept 5 per cage and not stressed. Stressed groups were subjected to either CS for 3, 7, 14days+restraint stress (RS) or IS for (11days) before this treatment was applied. Crowded rats were remained (24 in one cage) and RS rats were restrained for 10min. Total CORT, ACTH and IL-1β levels were measured using commercially available kits. Social CS for 3days significantly increased plasma IL-1β level. Social IS increased plasma IL-1β level after longer period of subsequent CS 7 and 14days, than ACTH and CORT, after 3 and 7days. Prior IS significantly increased plasma IL-1β level induced by subsequent combined CS for 3days+acute RS, but significantly or totally inhibited the acute stress-induced increase of plasma IL-1β level after 7 and 14days of combined stress. IS, by contrast, strongly inhibited the increase of plasma ACTH and CORT level induced by combined CS+acute RS. Chronic IS augments the changes of IL-1β level induced by a longer crowding period than ACTH and CORT. Modulatory action of IL-1β and pituitary-adrenocortical hormones adaptation to chronic social stress is asynchronous.

The non-peptide CRH1-antagonist CP-154,526 elicits a paradoxical route-dependent activation of the HPA axis

The corticotropin-releasing hormone (CRH) plays an important role in mediating physiological response to stress and is thought to be involved in the development of various psychiatric disorders. In this paper, we compare the differences between the effect of intraperitoneal (i.p.) and intraarterial (i.a.) administration of the non-peptide CRH1 antagonist CP-154,526 (CP) (10 and 20mg/kg) on plasma adrenocorticotropic hormone levels (ACTH), heart rate, MAP, and c-Fos expression in the paraventricular nucleus of the hypothalamus. Intraperitoneal, but not i.a., injection of CP resulted in an increase in plasma ACTH (from 105±13 to 278±51pg/ml after 20mg/kg). This effect was accompanied by a dramatic increase in c-Fos expression in cells immunoreactive for CRH in the paraventricular nucleus of the hypothalamus. When the drug was administered i.p., CP-induced activation of the HPA appears to mask the inhibitory effect of CP on stress-induced ACTH secretion, an effect which was readily apparent when the drug was given i.a. Intraperitoneal administration of CP also increased the baseline MAP which may account for previous reports that treatment with this drug attenuated the increases associated with stress. CP given by either route had no effect on baseline heart rate or stress-induced tachycardia. Thus, in all studies in which CP 154,526 is given, the route of delivery must be given careful consideration.

Bicuculline, a GABAA-receptor antagonist, blocked HPA axis activation induced by ghrelin under an acute stress

Ghrelin is a peptide of 28 amino acids with a homology between species, which acts on the central nervous system to regulate different actions, including the control of growth hormone secretion and metabolic regulation. It has been suggested that central ghrelin is a mediator of behavior linked to stress responses and induces anxiety in rodents and birds. Previously, we observed that the anxiogenic-like behavior induced by ghrelin injected into the intermediate medial mesopallium (IMM) of the forebrain was blocked by bicuculline (a GABAA receptor competitive antagonist) but not by diazepam (a GABAA receptor allosteric agonist) in neonatal meat-type chicks (Cobb). Numerous studies have indicated that hypothalamic–pituitary–adrenal (HPA) axis activation mediates the response to stress in mammals and birds. However, it is still unclear whether this effect of ghrelin is associated with HPA activation. Therefore, we investigated whether anxiety behavior induced by intra-IMM ghrelin and mediated through GABAA receptors could be associated with HPA axis activation in the neonatal chick. In the present study, in an Open Field test, intraperitoneal bicuculline methiodide blocked anxiogenic-like behavior as well as the increase in plasma ACTH and corticosterone levels induced by ghrelin (30pmol) in neonatal chicks. Moreover, we showed for the first time that a competitive antagonist of GABAA receptor suppressed the HPA axis activation induced by an anxiogenic dose of ghrelin. These results show that the anxiogenic ghrelin action involves the activation of the HPA axis, with a complex functional interaction with the GABAA receptor.

Ketamine modulates fetal hemodynamic and endocrine responses to umbilical cord occlusion.

Umbilical cord occlusion (UCO) is a hypoxic insult that has been used to model birth asphyxia and umbilical cord compression in utero. UCO triggers vigorous neural and endocrine responses that include increased plasma ACTH and cortisol concentrations, increased blood pressure (BP), and decreased heart rate (HR). We have previously reported that ketamine, a noncompetitive N‐methyl‐D‐aspartate receptor antagonist, can modify the fetal hemodynamic and ACTH responses to ventilatory hypoxia and cerebral ischemia‐reperfusion. We performed the present experiments to test the hypothesis that ketamine has similar effects on the neuroendocrine and cardiovascular responses to UCO. Fetal sheep were chronically catheterized at gestational day 125. Ketamine (3 mg/kg) was administered intravenously to the fetus 10 min prior to the insult. UCO was induced for 30 min by reducing the umbilical vein blood flow until fetal PaO2 levels were reduced from 17 ± 1 to 11 ± 1 mm Hg. UCO produced an initial increase on fetal BP in both control and ketamine groups (P = 0.018 time), followed by a decrease in the control group, but values remained higher with ketamine. HR decreased after UCO (P = 0.041 stimulus*time) in both groups, but the reduction was greater initially in control compared to ketamine groups. Fetal Pa CO 2 levels increased after UCO (P < 0.01 stimulus*time), but values were higher in the control versus ketamine groups. UCO significantly decreased fetal pH values (P < 0.01 stimulus*time) with a greater effect on the control versus ketamine group. Ketamine delayed the cortisol responses to UCO (P < 0.001 stimulus*time), and UCO produced a robust increase in ACTH levels from 19 ± 2 to 280 ± 27 pg/mL (P < 0.001 stimulus*time), but there were no differences in ACTH levels between UCO groups. We conclude that ketamine augmented the cardiovascular response to UCO, but did not alter the ACTH response to UCO.

CRF-R1 activation in the anterior-dorsal BNST induces maternal neglect in lactating rats via an HPA axis-independent central mechanism

Adequate maternal behavior in rats requires minimal corticotropin-releasing factor receptor (CRF-R) activation in the medial-posterior bed nucleus of the stria terminalis (mpBNST). Based on the architectural heterogeneity of the BNST and its distinct inter-neural connectivity, we tested whether CRF-R manipulation in another functional part, the anterior-dorsal BNST (adBNST), differentially modulates maternal behavior.We demonstrate that in the adBNST, activation of CRF-R1 reduced arched back nursing (ABN) and nursing, whereas activation of CRF-R2 resulted in an initial reduction in nursing but significantly increased the incidence of ABN 5h after the treatment. Following stressor exposure, which is detrimental to maternal care, ABN tended to be protected by CRF-R1 blockade. Maternal motivation, maternal aggression, and anxiety were unaffected by any manipulation. Furthermore, under basal and stress conditions, activation of adBNST CRF-R1 increased plasma ACTH and corticosterone concentrations, whereas stimulation of adBNST CRF-R2 increased basal plasma ACTH and corticosterone concentrations, but blocked the stress-induced increase in plasma corticosterone secretion. Moreover, both the CRF-R1 and -R2 antagonists prevented the stress-induced increase in plasma corticosterone secretion. Importantly, elevated levels of circulating corticosterone induced by intra-adBNST administration of CRF-R1 or -R2 agonist did not impact maternal care. Finally, Crf mRNA expression in the adBNST was increased during lactation; however, Crfr1 mRNA expression was similar between lactating and virgin rats.In conclusion, maternal care is impaired by adBNST CRF-R1 activation, and this appears to be the result of a central action, rather than an effect of elevated circulating levels of CORT. These data provide new insights into potential causes of disturbed maternal behavior postpartum.

Vitamin D3 May Ameliorate the Ketoconazole Induced Adrenal Injury: Histological and Immunohistochemical Studies on Albino Rats.

Ketoconazole (KZ) is used widely for treating the superficial, systemic fungal activities and hyperandrogenemic states. Its uses are limited by its deleterious effect on histological structure and function of the adrenal cortex. This study investigates whether vitamin D3 supplement can ameliorate the morphological changes induced by KZ.Thirty four adult male albino rats were randomized into control group (Group I) which was subdivided into: control 1 (n=7) and control 2 (n=7): In control 1, rats were intraperitoneal (I.P) injected once with 1 ml of polyethylene glycol-400 for 15 consecutive days and control 2 rats were injected I.P with (1 μg/kg) of vitamin D3 for the same period. Group II (n=10): rats were I.P injected with KZ (10 mg/100 g of body weight) once daily for 15 days; Group III (n=10): rats were I.P concomitantly injected with KZ and vitamin D3 similar doses to animals in groups II and control 2 respectively. Blood samples were collected to determine plasma ACTH, corticosterone and aldosterone levels. The right adrenal specimens sections were stained with Haematoxylin & Eosin and Masson Trichrome for histological studies and treated with Bax, Ubiquitin and vitamin D receptors for immunohistochemical studies.KZ induced adrenal cortical morphological changes in forms of disturbed adrenocorticocyte cytological architecture, nuclear changes, and intracellular lipid accumulation. KZ also increased adrenal Bax and Ub but decreased the vitamin D receptors immunopositive staining expression, in addition to increased plasma ACTH as well as decreased corticosterone and aldosterone levels. These changes were ameliorated by supplementing with vitamin D3.

Antisense versus proopiomelanocortin mRNA reduces vascular risk in a murine model of type-2 diabetes following stress exposure in early post-natal life

Mechanisms of vascular complications in type-2 diabetes patients and animal models are matter of debate. We previously demonstrated that a double-stress model applied to male mice during nursing period produces enduring hyperfunction of endogenous opioid and adrenocorticotropin (ACTH)-corticosteroid systems, accompanied by type-2 diabetes-like alterations in adult animals. Administration of the opioid receptor antagonist naloxone, or of an antisense oligodeoxynucleotide versus proopiomelanocortin mRNA, capable to block the pro-opiomelanocortin-derived peptides β-endorphin and ACTH, selectively prevent these alterations. Here, we investigated alterations produced by our stress model on aorta endothelium-dependent relaxation and contractile responses. Mice, stressed during nursing period, showed in the adulthood hormonal and metabolic type-2 diabetes-like alterations, including hyperglycemia, increased body weight and increased plasma ACTH and corticosterone levels. Ex vivo isolated aorta rings, gathered from stressed mice, were less sensitive to noradrenaline-induced contractions versus controls. This effect was blocked by nitric-oxide synthase-inhibitor l-NG-nitroarginine added to bath organ solution. Aorta rings relaxation caused by acetylcholine was enhanced in stressed mice versus controls, but following treatment with the nitric-oxide donor sodium nitroprusside, concentration-relaxation curves in aorta from stressed groups were similar to controls. Therefore, vascular response alterations to physiologic-pharmacologic stimuli were apparently due to nitric-oxide hyperfunction-dependent mechanisms. Aorta functional alterations, and plasma stress hormones enhancement, were prevented in mice stressed and treated with antisense oligodeoxinucleotide, addressed to reduce ACTH- and corticosteroid-mediated hyperfunction. This study demonstrates the key role of ACTH-corticosteroid axis hyperfunction for the triggering of vascular conditions in male adult rodents following postnatal stress in a type-2 diabetes model.

Neuropeptide Y1 receptor is a key element in stress response to food deprivation (1126.7)

The hypothalamic‐pituitary adrenal (HPA) axis functions as a default pathway for the maintenance of energy homeostasis. Food restriction or deprivation leads to prolonged HPA axis activation but the exact mechanism of this continuous HPA activation is not yet well understood. Our experiments were designed to determine whether neuropeptide Y (NPY) Y1 receptors participate in the stress response to food deprivation since NPY expression is elevated during periods of fasting. Food deprivation of male rats for 24 hours caused weight loss, adrenal gland hypertrophy and increased plasma ACTH and corticosterone concentrations. Food deprivation increased NPY mRNA expression in arcuate and brainstem C2/A2 nuclei areas that are known to project to the hypothalamic paraventricular nucleus (PVN). While the total area of CRH mRNA positive cells in the PVN decreased during food deprivation, the CRH mRNA signal intensity increased in the remaining active cells. Food deprivation also increased pCREB‐ir expression in PVN, an indication for neuronal activation. A majority of pCREB‐positive cells were CRH/Y1‐ir neurons. Infusion into the PVN of 1 nmol BIBP3226, a specific Y1 receptor antagonist, eliminated the elevated corticosterone blood levels in food‐deprived animals. Our observations support the notion that hypothalamic NPY Y1 receptors expressed by CRH neurons are pivotal for triggering a strong stress response during periods of food deprivation.Grant Funding Source: Supported by NIMH 62621

Relaxin-3 stimulates the neuro-endocrine stress axis via corticotrophin-releasing hormone

Relaxin-3 is a member of the insulin superfamily. It is expressed in the nucleus incertus of the brainstem, which has projections to the hypothalamus. Relaxin-3 binds with high affinity to RXFP1 and RXFP3. RXFP3 is expressed within the hypothalamic paraventricular nucleus (PVN), an area central to the stress response. The physiological function of relaxin-3 is unknown but previous work suggests a role in appetite control, stimulation of the hypothalamic-pituitary-gonadal axis and stress. Central administration of relaxin-3 induces c-fos expression in the PVN and increases plasma ACTH levels in rats. The aim of this study was to investigate the effect of central administration of human relaxin-3 (H3) on the hypothalamic-pituitary-adrenal (HPA) axis in male rodents in vivo and in vitro. Intracerebroventricular (i.c.v) administration of H3 (5 nmol) significantly increased plasma corticosterone at 30 min following injection compared with vehicle. Intra-PVN administration of H3 (1.8-1620 pmol) significantly increased plasma ACTH at 1620 pmol H3 and corticosterone at 180-1620 pmol H3 at 30 min following injection compared with vehicle. The stress hormone prolactin was also significantly raised at 15 min post-injection compared with vehicle. Treatment of hypothalamic explants with H3 (10-1000 nM) stimulated the release of corticotrophin-releasing hormone (CRH) and arginine vasopressin (AVP), but H3 had no effect on the release of ACTH from in vitro pituitary fragments. These results suggest that relaxin-3 may regulate the HPA axis, via hypothalamic CRH and AVP neurons. Relaxin-3 may act as a central signal linking nutritional status, reproductive function and stress.

Recurrent Pituitary Macroadenoma with Increased Plasma ACTH Precursors that Cross-React in a Commonly Used ACTH Immunoassay

adrenocorticotropic hormone

Regulation of Hypothalamic-Pituitary-Adrenal Axis by Circulating Free Fatty Acids in Male Wistar Rats: Role of Individual Free Fatty Acids

We previously showed that a fall in the plasma free fatty acid (FFA) level increases plasma corticosterone levels in rats by activating the hypothalamic-pituitary-adrenal axis. In the present study, we tested whether this regulation is mediated by specific or all species of FFAs. Nicotinic acid (NA) (30 μmol/h) was infused in rats to decrease plasma FFAs and increase plasma ACTH and corticosterone. The NA infusion was combined with an infusion of lipids with different FFA compositions to selectively prevent falls in individual FFA levels; coconut, olive, and safflower oils (n = 7 for each), which are predominantly (>70%) composed of saturated, monounsaturated (oleic acid), and polyunsaturated (linoleic acid) FFAs, respectively, were used. At an infusion rate (0.1 g/h) that only partially prevented a fall in the total FFA level, coconut oil, but not olive or safflower oil, completely prevented NA-induced increases in plasma ACTH or corticosterone, suggesting that these responses are mainly mediated by saturated FFAs. In addition, quantification of individual FFA species in the blood using FFA-specific fluorescent probes revealed that plasma corticosterone and ACTH correlated significantly with plasma palmitate but not with other FFAs, such as oleate, linoleate, or arachidonate. Taken together, our data suggest that the regulation of the hypothalamic-pituitary-adrenal axis by FFAs is mainly mediated by the saturated fatty acid palmitate, but not by unsaturated fatty acids, such as oleate and linoleate.