Adrenal Stimulation Research Articles

Clinical diagnosis and treatment of 21-hydroxylase deficiency nonclassic congenital adrenal hyperplasia complicated by testicular adrenal rest tumors(one-case report)

Objective To assess the clinical diagnosis and treatment of 21-hydroxylase deficiency nonclassic congenital adrenal hyperplasia (NCCAH) complicated by testicular adrenal rest tumors (TART), thus to improve the recognition of the disease. Methods The clinical data of one patient of NCCAH with TART from our department in 2016 were retrospectively studied, and were analyzed combined with related literature, and the diagnosis was established for treatment. Results The patient was a 17 years old boy.At the age of seven began to appear the pubic hair, voice and other secondary sexual performance.More than their big penis development was significantly higher than their peers.At the age of 12 found bilateral testicular gradually enlarged and attendance.Physical examination: bilateral testicular swelling and a sense of nodules, hard texture, epididymis, normal bilateral varicocele.Laboratory exam indications showed increased levels of progesterone(P), adrenocorticotropic hormone(ACTH), 17 hydroxyprogesterone(17α-OHP), aaldosterone(ALD), 17-hydroxyl corticosteroids(17-OHCS), 17-ketone corticosteroids(17-KS). By the ACTH stimulating test, 17α-OHP was increased.Bilateral testes MRI: irregular bilateral testes, signal, see in space.Enhanced scan lesions uniform reinforcement, germ cell tumors to row.Adrenal CT: bilateral adrenal hyperplasia.Testicular biopsy: testicular adrenal genital syndrome . Genetic testing: CYP21A2 heterozygous mutations.The above test results were diagnosed of NCCAH 21-OHD with TART.The patient was orally given 10mg/d prednisone 2 time.3 months after treatment, the 17α-OHP, CO and sex hormones returned to normal.Review the adrenal CT showed significant bilateral adrenal shrink, Pa/testis tubercle was narrow, but not obvious.Semen routine still suggested no sperm, considering the TART medical treatment effect was poor.Hence, further line tumor removed, followed up for 3 months without tumor recurrence at present. Conclusion NCCAH complex and varied clinical manifestations and hidden.Not easy to be noticed by patients and clinicians.For the early childhood in pubic hair growth accelerated leading to premature epiphyseal fusion and make the adult height is short stature consideration should be given to the disease.Further lines of sex hormones, adrenal related endocrine examination, genetic testing and ACTH stimulating test, etc.If concurrent bilateral testicular nodules, should consider to merge TART may.Testicular biopsy can be clear.Treatment can choose according to TART classification of glucocorticoid (a hormone steroid) or surgical treatment, concrete scheme should be individualized. Key words: 21-hydroxylase deficiency; Adrenal cortex diseases; Testicular adrenal rest tumors

Subspecies-specific response to ACTH challenge test in the house mouse (Mus musculus)

Long term changes in hormonal levels of small and rare animal species can be effectively monitored by non-invasive methods such as immunoenzymatic analysis. These methods generally analyze metabolites instead of the hormone itself and thus do not invade the organism. However, they can be influenced by many factors, so before they are used, they need to be validated. For this purpose we used the “ACTH challenge” test based on stimulating the animal’s adrenocortical activity and measuring the consequent increase of the level of its glucocorticoid (“stress”) hormones. Specifically, we measured concentrations of fecal glucocorticoid metabolites of two house mouse subspecies, Mus musculus musculus and M. m. domesticus. Using polyclonal antibody we investigated the mice’s naturally occurring circadian fluctuation and their reaction to the adrenal stimulation. This study confirmed that the selected method is suitable for analysis of fecal corticosterone metabolites in the wild house mouse. More importantly, we revealed a subspecies-specific stress response at the level of corticosterone production: while the significant effect of ACTH was proved in both subspecies, a notable adrenocortical reaction was also elicited by injecting the saline solution in M. m. domesticus. Our results thus highlight the importance of considering potential cryptic variation within the species under study when designing projects on adrenal stress hormone assessments.

Evaluation of Early Corticosteroid Therapy in Management of Pediatric Septic Shock in Pediatric Intensive Care Patients: A Randomized Clinical Study.

Septic shock is a major healthcare problem. Adrenal insufficiency (AI) in children with septic shock is a recognized complication, yet is controversial regarding its management and effect on mortality. According to the current guidelines, children with risk factors for AI should receive a stress dose of steroids in step 3 of treatment. This study aimed to evaluate and compare early corticosteroid therapy with the traditional use of steroids among pediatric septic shock patients. This prospective randomized interventional clinical study included 3 groups of patients (32 each) and was conducted in Alexandria University pediatric intensive care unit. By protocol, the first group received steroids in step 3 of the treatment according to the current international guidelines (group A), and the second group was managed as group A and was tested for AI by adrenal stimulation test using intramuscular adrenocorticotropic hormone (cosyntropin) (group B). The third group received steroids at the start of fluid therapy (group C). A fourth group (group D) was created by adding patients from groups A and B who needed corticosteroids in the third stage of therapy according to the international protocol in 1 group. All patients were evaluated for basal serum cortisol and plasma adrenocorticotropic hormone concentrations. The data showed a statistically significant shorter shock reversal time among patients receiving corticosteroids at the start of treatment compared with those who received it at the third step of treatment (P = 0.046); however, mortality was not statistically different among the groups. In addition, there was no superinfection in cases receiving early steroid therapy. Early use of corticosteroid in patients with septic shock might shorten the shock reversal time without increase in mortality or superinfection.

3:00 PMAbstract No. 197 - The value of adrenal vein sampling pre-ACTH stimulation, for the diagnosis of surgically remediable hyperaldosteronism

3:00 PMAbstract No. 197 - The value of adrenal vein sampling pre-ACTH stimulation, for the diagnosis of surgically remediable hyperaldosteronism

Indications and future perspectives in the pharmacological treatment of hypercortisolism

The hypercortisolism is a rare endocrine disease characterized by an autonomous steroid secretion or excessive adrenal stimulation by ACTH. the Surgical removal of the lesion directly responsible hypercortisolism represents the treatment of choice. When neurosurgery for pituitary adenoma is contraindicated, radiotherapy is candidate as the second line of therapy. Currently, the recent advances in medical therapy provide a viable alternative to surgery and radiotherapy, when these are not feasible or followed by relapses (present in more than one third of cases) of the underlying disease. Recently, also in Italy, are available pharmacological agents with central activity (pasireotide) specifically indicated for treating Cushing's disease together with peripherally acting drugs (metyrapone and ketoconazole) that are used in a broader spectrum of hypercortisolemic clinical pictures. In addition, drugs active in the inhibition of steroidogenesis provide a valid support to the patient's surgical preparation allowing the reduction or normalization of plasma cortisol levels.

Etiopathogeny of Primary Adrenal Hypercortisolism.

Primary adrenal hypercortisolism is mainly due to cortisol-producing adrenocortical adenomas, bilateral micronodular or macronodular disease, and adrenal carcinomas. Important advances in the pathophysiology of primary adrenal hypercortisolism have been made in the last few years, partly through the use of new molecular biology tools. Most adrenal abnormalities leading to increased cortisol production involve somatic or germinal mutations of genes encoding elements of the cyclic AMP/protein kinase A signaling pathway, as shown in adrenal adenomas in 2014. One peculiar condition is primary macronodular adrenal hyperplasia (PMAH), which has given rise to new pathophysiological concepts such as regulation of cortisol secretion by illegitimate ligands through aberrant expression of G protein-coupled transmembrane receptors in adrenal nodules and stimulation of cortisol production by local adrenocorticotropic hormone production through autocrine/paracrine mechanisms. These findings provide a basis for the development of targeted therapies as an alternative to surgery. The recent identification of germinal mutations of ARMC5 in PMAH raises the possibility that this is much more frequently an inherited disease than previously suspected. It also offers the possibility of earlier diagnosis of PMAH by genetic screening and, hopefully, of earlier intervention to prevent the onset of hypercortisolism and its complications. The pathophysiology of Cushing's syndrome associated with a subset of adrenal adenomas, including subclinical cortisol-secreting incidentalomas and adrenal carcinomas, remains to be determined.

Adrenal Function Testing Following Hormone Therapy for Infantile Spasms: Case Series and Review of Literature.

Prednisolone and adrenocorticotropic hormone (ACTH) are “hormone” therapies for infantile spasms. There is limited data on the occurrence of decreased adrenal reserve or signs of clinical adrenal insufficiency after hormone therapy. This is a retrospective medical record review of patients referred to our Infantile Spasms Program. Our standardized infantile spasms management guideline began in September 2012 and initially included a post-hormone laboratory assessment of adrenal function. Medical records were assessed for hormone treatments, adrenal function testing, and signs of adrenal insufficiency. Forty-two patients who received one or both hormone therapies met inclusion criteria. A post-hormone laboratory assessment of adrenal function was done in 14 patients. Of these 14 patients, 2 had an abnormal laboratory assessment of adrenal function, both by adrenal stimulation testing – one after ACTH and one after prednisolone. One patient received hydrocortisone replacement and the other received stress dose hydrocortisone as needed; neither patient developed signs of adrenal insufficiency. Another patient treated with both types of hormone therapy in tandem, who did not have a post-hormone laboratory assessment, developed signs of mild adrenal insufficiency and required replacement hydrocortisone. Our study suggests that adrenal suppression can occur after modern hormone therapy regimens. We found two patients with abnormal adrenal function testing after hormone therapy and another patient with signs adrenal insufficiency. Given the seriousness of adrenal crisis, caregiver education on the signs of adrenal insufficiency is critical. Greater vigilance may be indicated in patients receiving both types of hormone therapy in tandem. Although a routine post-hormone laboratory assessment of adrenal function may not be feasible in all patients, replacement or stress dose hydrocortisone is necessary for all patients with suspected adrenal insufficiency.

Ontogeny of the corticotrophin-releasing hormone system in slow- and fast-growing chicks (Gallus gallus)

Selective breeding has caused striking phenotypic differences among chickens. For example, the broiler, a fast-growing phenotype, is a relatively heavy bird selected for meat production while the layer, a slower-growing, lighter bird, was developed for egg production. Broilers are prone to early obesity and show physiological and behavioural differences in response to stressors compared with layers. However, the genetic causes of the differences in the responses to stressors between them have not been determined. The purpose of the present study was to compare the ontogeny of the corticotropin-releasing hormone (CRH) system between broilers and layers, because the CRH system plays a major role in regulating stress. We found that fast-growing broilers showed significantly lower levels of diencephalic CRH mRNA expression at post-hatch days 8 and 15 and pituitary CRH receptor 1 mRNA expression from the embryonic to post-hatch stage than slower-growing layers. However, a significantly higher level of CRH-binding protein (CRH-BP), which inactivates CRH and prevents pituitary–adrenal stimulation, was found in broilers compared with layers. Indeed, broilers showed significantly lower levels of plasma corticosterone (CORT) than layers. Subjecting birds to isolation stress did not alter the CORT level of broilers, but increased that of layers. Collectively, the stress-coping actions of the CRH system via the hypothalamic–pituitary–adrenal (HPA) axis might be less responsive in broilers than in layers due to differential gene expression. Together, the present results provide evidence that genetic selection has altered gene expression in the CRH system of the fast-growing broiler, causing blunted HPA axis activity in response to stressors.

Application of low8intensity laser for adrenal stimulation in males with chronic obstructive pulmonary disease and hormonal disorders

The aim of this study was to investigate a role of adrenal function stimulation in patients with stage 3 chronic obstructive pulmonary disease (COPD). Methods . Blood levels of cortisol, aldosterone and testosterone were measured in 82 males with severe COPD and in 25 healthy subjects. The study involved three patient groups: 41 patients with stage 3 COPD who received lowintensity infrared laser radiation with a frequency of 80 Hz applied on the adrenal gland area additionally to the standard therapy; 26 patients with stage 3 COPD who received standard therapy only and 15 patients with COPD who received standard therapy and a placebo exposure using a switched off laser device. Results . A significant reduction in blood cortisol, aldosterone and testosterone levels in patients with stage 3 COPD was found. A role of adrenal function stimulation was confirmed in patients with stage 3 COPD. Conclusion. Severity of adrenal hormonal disorders correlates directly to severity of COPD. Treatment of male patients with stage 3 COPD should include adrenal hormone correction using both medication and nonmedication on individual basis. The lowintensity laser radiation of adrenal area could significantly increase blood cortisol level and improve quality of life of the patients.

Dosagem de metabólitos de glucocorticoides e progesterona em fezes de papagaio-verdadeiro (Amazona aestiva)

Os objetivos do presente trabalho foram avaliar as concentrações fecais de metabólitos de glicocorticoides, mensurados por enzimaimunoensaio, empregando-se anticorpos contra cortisol, e por radioimunoensaio, empregando-se anticorpo contra corticosterona, e dos metabólitos da progesterona, mensurados por raioimunoensaio empregando-se anticorpo contra progesterona, em papagaios-verdadeiros (Amazona aestiva) após desafio com ACTH. A estimulação da adrenal com 25 UI/animal de ACTH resultou na elevação das concentrações de metabólitos de glicocorticoides, mas não modificou a dos metabólitos da progesterona fecal em papagaio-verdadeiro. Embora não tenha sido observada a sincronização dos picos de excreção fecal dos metabólitos de glicocorticoides mensurados por enzimaimunoensaio e radioimunoensaio, houve dois picos de excreção, um entre 2 e 4 horas e outro entre 8 e 10 horas. Apesar dos picos, não foram detectados efeitos de Grupos (Tratamento x Controle), momento (horas de coleta) ou sexo (macho x fêmea) nos resultados observados nas concentrações fecais de metabólitos de glicocorticoides e de progesterona, com os métodos empregados.

Hypotension following Patent Ductus Arteriosus Ligation: The Role of Adrenal Hormones

To test the hypothesis that an impaired adrenal response to stress might play a role in the hypotension that follows patent ductus arteriosus (PDA) ligation. We performed a multicenter study of infants born at <32weeks' gestation who were about to undergo PDA ligation. Serum adrenal steroids were measured 3 times: before and after a cosyntropin (1.0μg/kg) stimulation test (performed before the ligation), and at 10-12hours after the ligation. A standardized approach for diagnosis and treatment of postoperative hypotension was followed at each site. A modified inotrope score (1×dopamine [μg/kg/min]+1×dobutamine) was used to monitor the catecholamine support an infant received. Infants were considered to have catecholamine-resistant hypotension if their greatest inotrope score was >15. Of 95 infants enrolled, 43 (45%) developed hypotension and 14 (15%) developed catecholamine-resistant hypotension. Low postoperative cortisol levels were not associated with the overall incidence of hypotension after ligation. However, low cortisol levels were associated with the refractoriness of the hypotension to catecholamine treatment. In a multivariate analysis: the OR for developing catecholamine-resistant hypotension was OR 36.6, 95% CI 2.8-476, P=.006. Low cortisol levels (in infants with catecholamine-resistant hypotension) were not attributable to adrenal immaturity or impairment; their cortisol precursor concentrations were either low or unchanged, and their response to cosyntropin was similar to infants without catecholamine-resistant hypotension. Infants with low cortisol concentrations after PDA ligation are likely to develop postoperative catecholamine-resistant hypotension. We speculate that decreased adrenal stimulation, rather than an impaired adrenal response to stimulation, may account for the decreased production.

Nonylphenol effects on the HPA axis of the bioindicator vertebrate, Podarcis sicula lizard

Nonylphenol (NP) is an endocrine disruptor widely distributed in the environment. It accumulates in the lipids of living organisms and enters the human food chain. The main source of human exposure is expected to be food, drinking water and foodstuff contaminated through leaching from packaging or pesticide formulation applications. NP acts as an estrogenic compound and it is able to mimic the action of estradiol 17β (E2) by binding to the estrogen receptor (ER). The aim of the present study was to investigate the NP effects on the hypothalamic–pituitary–adrenal gland (HPA) axis of the bioindicator Podarcis sicula lizard. A time-dependent stimulation of the HPA axis and variations of both catecholamine plasma levels were showed. Moreover, NP effects on adrenal gland morphology were evaluated by light and transmission electron microscopy. Clear morphological signs of adrenal gland stimulation such as an increase of steroidogenic cord diameter and vascularization, a strong escalation of adrenaline cell number and a decrease of noradrenaline cells were observed. The notably elevated levels of adrenal hormones suggested a permanent turning on of hypothalamic corticotropin releasing factor (CRF) secretion together with a lack of the negative feedback of HPA axis, perturbing systemic responses of the organism. Our data may help to predict the biological alterations induced by NP and to extend its impact upon adrenal function.

Abstract C133: Adrenal stimulation of CRPC growth in an in vitro co-culture model.

Abstract Introduction: In the majority of castration resistant prostate cancers (CRPC), the AR is still active despite low serum testosterone levels. Among other mechanisms of AR-activation, intratumoral androgen synthesis, either via conversion of adrenal androgens or de novo synthesis from cholesterol, is a mechanism of castration resistance. In a previous study, we found that clinical CRPC samples only expressed markers for conversion of adrenal androgens and not for de novo synthesis. In this study, we compared growth stimulation of hormone-naïve prostate cancer (PC) and CRPC cell lines by adrenal androgens (conversion) or androgen precursors (de novo synthesis) and subsequently tested a novel co-culture model to mimic adrenal stimulation of (CR)PC. Materials and methods: VCaP and DuCaP CRPC lines were generated by long-term culturing in steroid stripped medium (DCC) with or without the anti-androgens bicalutamide or flutamide. To test cell growth stimulation, VCaP and DuCaP cells and their CRPC sublines were cultured in the presence of androgen precursors (pregnenolone and progesterone) or adrenal androgens (DHEA and androstenedione) at levels found in men. Cells were treated with either vehicle, the CYP17A1-inhibitor Abiraterone (0.1 μM) or the anti-androgen MDV3100 (1 μM). Cell proliferation was assessed by MTT-assay on day 9 with each experiment performed in triplicate. In the co-culture model, VCaP cells were cultured with human adrenal (H295R) cells in separate compartments between which only medium could diffuse freely, and treated with vehicle, Abiraterone (1 μM) or DHT (0.1 nM). Results: In VCaP and DuCaP and their CRPC derivatives, androgen precursors pregnenolone and progesterone did not induce additional cell growth compared to cell growth in DCC. In contrast, physiological levels of adrenal androgens stimulated cell growth, comparable to optimal stimulus by DHT. Adrenal androgen concentrations found in serum of H295R-bearing mice induced a similar growth-response. Treatment with Abiraterone could not block adrenal androgen induced growth, while MDV3100 blocked steroid-induced growth in all conditions. Co-culturing of VCaP cells with H295R cells induced optimal cell growth, which could be inhibited by treatment with Abiraterone. Conclusion: In VCaP and DuCaP cells and the CRPC sublines, the substrate for conversion of adrenal androgens induced growth, while precursors of de novo androgen synthesis did not. These data support our observations that growth of (CR)PC seems to rely more on conversion than on de novo androgen synthesis. Co-culturing PC cells with human adrenal cells using a 2-compartment system is a relevant model to test CRPC stimulation in vitro. We are currently generating an in vivo model by inoculating PC and H295R cells simultaneously in nude mice more accurately reflect human CRPC. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):C133. Citation Format: Jan Matthijs Moll, Wilma Teubel, Ian Hickson, Ralph Graeser, Guido Jenster, Wytske van Weerden. Adrenal stimulation of CRPC growth in an in vitro co-culture model. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr C133.

New insights into steroidogenesis in normo- and hyperandrogenic polycystic ovary syndrome patients

This study sought to examine corticosteroidogenic enzyme activities in normo- and hyperandrogenic polycystic ovary syndrome (PCOS) patients. This cohort study included 81 patients with biochemical hyperandrogenism and 41 patients with normal androgen levels. Enzyme activities were assessed according to the serum steroid product/precursor ratios at baseline and after adrenal stimulation. At baseline, in the delta 4 (Δ4) pathway, hyperandrogenic patients showed greater 17-hydroxylase and 17,20 lyase activities in converting progesterone (P4) into 17-hydroxyprogesterone (17-OHP4) and 17-hydroxypregnenolone (17-OHPE) into androstenedione (A) (p = 0.0005 and p = 0.047, respectively) compared to normoandrogenic patients. In the delta 5 (Δ5) pathway, the 17-hydroxylase and 17,20 lyase enzymes showed similar activities in both groups. Hyperandrogenic patients presented lower 21-hydroxylase, lower 11β-hydroxylase (p = 0.0001), and statistically significant increases in 3β-hydroxysteroid dehydrogenase II (3β-HSDII) activities (p < 0.0001). Following tetracosactrin stimulation, only the 17,20 lyase activity remained up-regulated in the Δ4 pathway (p < 0.0001). Hyperandrogenic patients had higher 17,20 lyase activity, both at baseline and after adrenal stimulation. Greater conversion of dehydroepiandrosterone (DHEA) into A with normal conversion of 17-OHPE to 17-OHP4 in hyperandrogenic PCOS patients indicated different levels of 3β-HSDII activity in adrenal cells, and hyperandrogenic patients had lower 11β-hydroxylase and 21-hydroxylase activities.

Validation of a low-dose adrenocorticotropic hormone stimulation test in healthy neonatal foals

To determine the lowest ACTH dose that would induce a significant increase in serum cortisol concentration and identify the time to peak cortisol concentration in healthy neonatal foals. Prospective randomized crossover study. 11 healthy neonatal foals. Saline (0.9% NaCl) solution or 1 of 4 doses (0.02, 0.1, 0.25, and 0.5 μg/kg [0.009, 0.045, 0.114, and 0.227 μg/lb]) of cosyntropin (synthetic ACTH) was administered IV. Serum cortisol concentrations were measured before and 10, 20, 30, 60, 90, 120, 180, and 240 minutes after administration of cosyntropin or saline solution; CBCs were performed before and 30, 60, 120, and 240 minutes after administration. Serum cortisol concentration was significantly increased, compared with baseline, by 10 minutes after cosyntropin administration at doses of 0.1, 0.25, and 0.5 μg/kg. Serum cortisol concentration peaked 20 minutes after administration of cosyntropin at doses of 0.02, 0.1, and 0.25 μg/kg, with peak concentrations 1.7, 2.0, and 1.9 times the baseline concentration, respectively. Serum cortisol concentration peaked 30 minutes after cosyntropin administration at a dose of 0.5 μg/kg, with peak concentration 2.2 times the baseline concentration. No significant differences were detected among peak serum cortisol concentrations obtained with cosyntropin administration at doses of 0.25 and 0.5 μg/kg. Cosyntropin administration significantly affected the lymphocyte count and the neutrophil-to-lymphocyte ratio. Results suggested that in healthy neonatal foals, the lowest dose of cosyntropin to result in significant adrenal gland stimulation was 0.25 μg/kg, with peak cortisol concentration 20 minutes after cosyntropin administration.

Letter to the Editor Adrenal function and MC1R gene analysis in a prepubertal girl with generalized hyperpigmentation:

Letter to the Editor Adrenal function and MC1R gene analysis in a prepubertal girl with generalized hyperpigmentation:

Negative Regulation of Eosinophil Production by Toll-Like Receptors

Abstract 1237Eosinophilia is a common clinical problem associated with numerous disorders such as atopic diseases, parasitic infections, hypereosinophilic syndrome (HES), and cancer. A marked decrease in circulating eosinophils, or eosinopenia, has long been associated with acute bacterial infections. Eosinopenia has been shown to be a sensitive and reliable marker for distinguishing between non-infectious and infection-associated sepsis in the intensive care unit setting. Eosinopenia with acute infection had been assumed to be secondary to the release of adrenal glucocorticoids in response to the stress of infection. However, animal studies performed in the 1970s demonstrated that inhibition of parasite-associated eosinophilia with acute bacterial infection was independent of adrenal stimulation; the investigator speculated that it was due to a direct effect on the eosinophil precursor. To date, the mechanism of infection-associated eosinopenia, and its potential for suppressing IL-5-mediated eosinophilia, has not been investigated.To study eosinophil development, we established an ex vivo liquid culture system in which we can follow the differentiation of murine eosinophil lineage-committed progenitors (EoPs) to mature functional effector eosinophils that express known eosinophil surface markers and granule proteins and respond to eosinophil-active chemoattractants. We demonstrate that murine eosinophil precursors express mRNA for six TLRs. Ligands for TLR2 heterodimers, TLR4 and TLR7, but not TLR3, inhibited eosinophil ex vivo growth by attenuating EoP proliferation in response to IL-5 stimulation. Exposure to heat-killed E. coli also resulted in diminished EoP proliferation. The developing eosinophils further responded to TLR activation with production of a subset of inflammatory cytokines, including IL-6, IL-10, TNF-alpha and CXCL10. Co-culturing of untreated EoPs with LPS-exposed EoPs resulted in reduced IL-5-mediated proliferation of the untreated EoPs, suggesting that EoPs secrete mediators in response to TLR activation that regulate their proliferation in an autocrine/paracrine manner. Neutralization of IFN-beta, but not IFN-alpha or IFN-gamma, partially protected developing eosinophils from the inhibitory effects of LPS. In vivo studies revealed that endotoxemia and bacteremia reduced numbers of EoPs in the bone marrow of wild-type mice. Further, LPS dose-dependently reduced hypereosinophilia in IL-5 transgenic mice, highlighting the potential therapeutic value of this approach even in an extreme IL-5-driven clinical state. Suppression of eosinophil production by TLR4 ligands is conserved between mice and humans as yield of eosinophils from human EoPs was reduced following LPS exposure. Taken together, these findings identify a mechanistic explanation for eosinopenia following bacterial infections and identify a novel therapeutic strategy for inhibiting eosinophil production and peripheral eosinophilia in eosinophil-associated diseases. Disclosures:No relevant conflicts of interest to declare.

Validation of a low-dose ACTH stimulation test in healthy adult horses

To determine the lowest ACTH dose that would induce a maximum increase in serum cortisol concentration in healthy adult horses and identify the time to peak cortisol concentration. Evaluation study. 8 healthy adult horses. Saline (0.9% NaCl) solution or 1 of 4 doses (0.02, 0.1, 0.25, and 0.5 μg/kg [0.009, 0.045, 0.114, and 0.227 μg/lb]) of cosyntropin (synthetic ACTH) were administered IV (5 treatments/horse). Serum cortisol concentrations were measured before and 30, 60, 90, 120, 180, and 240 minutes after injection of cosyntropin or saline solution; CBCs were performed before and 30, 60, 120, and 240 minutes after injection. For all 4 doses, serum cortisol concentration was significantly increased, compared with the baseline value, by 30 minutes after administration of cosyntropin; no significant differences were detected among maximum serum cortisol concentrations obtained in response to administration of doses of 0.1, 0.25, and 0.5 μg/kg. Serum cortisol concentration peaked 30 minutes after administration of cosyntropin at a dose of 0.02 or 0.1 μg/kg, with peak concentrations 1.5 and 1.9 times, respectively, the baseline concentration. Serum cortisol concentration peaked 90 minutes after administration of cosyntropin at a dose of 0.25 or 0.5 μg/kg, with peak concentrations 2.0 and 2.3 times, respectively, the baseline concentration. Cosyntropin administration significantly affected WBC, neutrophil, and eosinophil counts and the neutrophil-to-lymphocyte ratio. Results suggested that in healthy horses, administration of cosyntropin at a dose of 0.1 μg/kg resulted in maximum adrenal stimulation, with peak cortisol concentration 30 minutes after cosyntropin administration.

Preparing for hibernation in ground squirrels: adrenal androgen production in summer linked to environmental severity in winter

Summary1. At high latitudes, evolutionary adaptations focus on those that maximize survival, with hibernation being a major one used by many smaller mammals. Typically, mammalian hibernators overwinter in sites that are ≈0°C. However, in arctic regions, such sites do not exist, necessitating hibernation at sites well below 0°C. Lipid, the normal fuel of most hibernators, may not provide sufficient glucose needed by certain tissues to permit survival, with muscle breakdown being required. Critical to enhancing muscle stores are high concentrations of anabolic androgens prior to hibernation when the gonads are inactive.2. We compare and contrast androgen levels in arctic ground squirrels (AGS) (Urocitellus parryii Richardson) from the Yukon and Columbian ground squirrel (CGS) (U. columbianus Ord) from southern Alberta.3. In males, changes in testes mass over the active season were similar between AGS and CGS. In contrast, during the breeding and the nonbreeding, pre‐hibernation periods, androgen levels in AGS were 6–10 and 20–25 times, respectively, those of CGS. From the breeding to the pre‐hibernation periods, androgen levels declined 41% in AGS, but 86% in CGS. In females, androgen levels in AGS were high throughout the active season and, prior to hibernation, were 24 times those in CGS.4. In pre‐hibernating AGS, we determined the source of these high androgen levels from two studies. First, using a hormonal challenge protocol to probe the hypothalamic‐pituitary‐adrenal axis, we found that androgen levels in both females and males decreased ≥10% in response to suppression by dexamethasone (an artificial glucocorticoid that inhibits ACTH release) and increased ≥18% in response to direct adrenal stimulation by adrenocorticorticotropic homone (ACTH). Second, by sequential hormonal injections in males of gonadotropin‐releasing hormone (GnRH) and of ACTH coupled with gonadectomy (GDX), followed by adrenalectomy (ADX), we found that GnRH had no effect, whereas ACTH stimulated androgen levels by &gt;40%, both before and after GDX. After ADX, levels fell by 80%. Thus, the adrenals, not the gonads, are the source of these androgens.5. We hypothesize that pre‐hibernating AGS have evolved a solution seen in no other known mammal: exploiting the benefits of high adrenal androgen levels prior to hibernation to build muscle that is then catabolized overwinter. The unknown is how AGS have mitigated the costs of these high androgen levels.

Maternal dexamethasone treatment in late gestation induces precocious fetal maturation and delivery in healthy Thoroughbred mares

The foal requires an active hypothalamo-pituitary-adrenal (HPA) axis for organ maturation and post natal survival. Prenatal administration of synthetic glucocorticoids may provide an effective method for inducing fetal maturation safely in the mare. To determine whether dexamethasone administered to late pregnant mares: 1) will induce fetal maturation and precocious delivery; 2) is safe to use and 3) to identify endocrine responses in the mare and foal. Pregnant Thoroughbred mares received either 100 mg dexamethasone i.m. (treated n = 5) or 50 ml saline i.m. (control n = 5) at 315, 316 and 317 days of gestation. Plasma progestagens, cortisol and prostaglandin F(2α) metabolite (PGFM) concentrations were measured before and after treatment. The foals were weighed, the crown-rump length (CRL) measured and an adrenal stimulation test performed on Day 1. Dexamethasone significantly (P<0.01) reduced gestation length in treated mares without apparent adverse effects. Plasma progestagens increased (P<0.05), and cortisol and PGFM (P<0.05) decreased, following dexamethasone treatment compared with control mares. Foals were clinically mature but those from dexamethasone treated mares had reduced (P<0.05) CRL, but not bodyweights, compared with controls. Their cortisol concentrations increased following exogenous adrenocorticotrophic hormone stimulation but 2 foals from dexamethasone treated mares showed evidence of adrenal suppression. Dexamethasone stimulates precocious fetal maturation and delivery in healthy late pregnant mares. However, fetal HPA activity may be suppressed. Dexamethasone treatment could be used to improve foal viability in mares at risk of preterm delivery. The endocrine effects of such a therapy must be evaluated before clinical intervention with glucocorticoids can be recommended.