Clinical and molecular characterization of thirty Chinese patients with congenital lipoid adrenal hyperplasia.

Congenital lipoid adrenal hyperplasia (LCAH), as the most severe form of congenital adrenal hyperplasia (CAH), is caused by mutations in the steroidogenic acute regulatory protein (STAR). Affected patients were typically characterized by adrenal insufficiency in the first year of life and present with female external genitalia regardless of karyotype. Non-classic LCAH patients usually present from 2 to 4 years old with glucocorticoid deficiency and mild mineralocorticoid deficiency, even develop naturally masculinized external genitalia at birth when they have 46,XY karyotype. We described thirty patients from unrelated Chinese families, including three non-classic LCAH ones. Four novel mutations were reported, including c.556A > G, c.179-15G > T, c.695delG and c.306 + 3_c.306 + 6delAAGT. The c.772C > T is the most common STAR mutation in Chinese population, suggesting a possibility of founder effect. Enzymatic activity assay combined with clinical characteristics showed a good genotype-phenotype correlation in this study. Residual STAR activity more than 20 % may be correlated with non-classic LCAH phenotype. We support the perspective that onset age may be affected by multiple factors and masculinization should be the main weighting factor for diagnosis of non-classic LCAH. Compared with 46,XX LCAH patients, less 46,XY ones were found in our report. A less comprehensive inspection and an easy diagnosis due to classical phenotype both would reduce the possibility of 46,XY LCAH patients to be referred to specialists or geneticists.

STAR mutations causing non­classical lipoid adrenal hyperplasia manifested as familial glucocorticoid deficiency.

Familial glucocorticoid deficiency (FGD) is a rare autosomal recessive disease characterized by single cortisol deficiency but normal aldosterone and renin levels. Beginning from the discovery of the disease to that of the pathogenic genes over a period of 30 years, the development of gene detection technology has identified a large number of FGD­related genes. Despite the fact that the genetic defect underlying this disease is known for approximately 70% of the patients diagnosed with FGD, there are still several unknown factors causing it. FGD is divided into type 1, type 2 and non­classical type according to the mutant gene. The case described in the present study reported two patients, who were siblings, having skin hyperpigmentation and undergone treatment in adulthood. The gonadal development was normal and the proband had a 10­year­old son. Laboratory tests suggested glucocorticoid deficiency and a mild lack of mineralocorticoid, indicating hyponatremia and hypotension in the proband. In addition, cortisol deficiency was not affected by adrenocorticotropic hormone treatment, while the adrenal glands in the two patients did not show any hyperplasia. Gene analysis revealed two compound heterozygote mutations c.533T>A (p. Leu178Gln) and c.737A>G (p. Asp246Gly) in the steroid hormone acute regulatory protein (STAR) gene in both patients, which may have been obtained from their parents and the proband passed one of the mutations to her son. The present study results revealed that STAR mutations cause non­classic congenital lipoid adrenal hyperplasia in China.

General Adaptation in Critical Illness: Glucocorticoid Receptor-alpha Master Regulator of Homeostatic Corrections.

In critical illness, homeostatic corrections representing the culmination of hundreds of millions of years of evolution, are modulated by the activated glucocorticoid receptor alpha (GRα) and are associated with an enormous bioenergetic and metabolic cost. Appreciation of how homeostatic corrections work and how they evolved provides a conceptual framework to understand the complex pathobiology of critical illness. Emerging literature place the activated GRα at the center of all phases of disease development and resolution, including activation and re-enforcement of innate immunity, downregulation of pro-inflammatory transcription factors, and restoration of anatomy and function. By the time critically ill patients necessitate vital organ support for survival, they have reached near exhaustion or exhaustion of neuroendocrine homeostatic compensation, cell bio-energetic and adaptation functions, and reserves of vital micronutrients. We review how critical illness-related corticosteroid insufficiency, mitochondrial dysfunction/damage, and hypovitaminosis collectively interact to accelerate an anti-homeostatic active process of natural selection. Importantly, the allostatic overload imposed by these homeostatic corrections impacts negatively on both acute and long-term morbidity and mortality. Since the bioenergetic and metabolic reserves to support homeostatic corrections are time-limited, early interventions should be directed at increasing GRα and mitochondria number and function. Present understanding of the activated GC-GRα's role in immunomodulation and disease resolution should be taken into account when re-evaluating how to administer glucocorticoid treatment and co-interventions to improve cellular responsiveness. The activated GRα interdependence with functional mitochondria and three vitamin reserves (B1, C, and D) provides a rationale for co-interventions that include prolonged glucocorticoid treatment in association with rapid correction of hypovitaminosis.

The management of glucocorticoid deficiency: Current and future perspectives.

Glucocorticoid deficiency is the clinical state characterised by inadequate cortisol production. It may occur due to the primary failure of the adrenal cortex or to lack of stimulation of the adrenal cortex by adrenocorticotropic hormone. The aim of treatment of glucocorticoid deficiency is to mimic the normal physiological secretion of cortisol, in order to normalise quality of life and reverse pathological sequelae. However, the diurnal rhythm of cortisol secretion is difficult to reproduce with exogenous glucocorticoid therapy. There is wide inter- and intra-individual variability of in the dynamics of physiological glucocorticoid secretion, and glucocorticoid preparations that are currently available cannot reproduce physiological profiles. In addition, there are no reliable biomarkers to determine the adequacy of treatment. The treatment of acute glucocorticoid deficiency/ adrenal crisis involves prompt recognition and administration of parenteral hydrocortisone, rehydration, and management of electrolyte abnormalities. In the management of chronic glucocorticoid deficiency, the prevention of adrenal crisis must be balanced with avoidance of the long-term adverse effects of over-replacement. This requires close collaboration with the patient, for whom education and empowerment in the management of glucocorticoid deficiency, and the prevention of crises, are crucial.

Acute Statin Administration Reduces Levels of Steroid Hormone Precursors.

Cholesterol-lowering statin drugs are used by approximately 25% of US adults 45 years of age and older and frequency of use is even higher among the elderly. Cholesterol provides the substrate for steroid hormone synthesis and its intracellular concentrations are tightly regulated. Our aim was to evaluate whether statin use acutely changes the circulating levels of cortisol, other glucocorticoid precursor molecules and their metabolites. Fourteen subjects not taking statins were administered a single oral dose (2 mg) of pitavastatin. Blood samples collected at baseline and 24 h post-treatment were analyzed for plasma cholesterol and steroid hormone profile. A parallel study in mice entailed the administration of atorvastatin (10 mg/kg) via orogastric delivery for three consecutive days. Cholesterol and corticosterone levels were quantified at baseline and at 1-day and 1-week post-treatment. Several precursor molecules in the steroidogenic pathway (corticosterone, cortisone, and 11-deoxycortisol) were significantly decreased 24 h after administration of a single dose of pitavastatin in human study subjects. Their circulating cholesterol concentrations were unchanged. In mice, there were no significant differences in serum cholesterol or corticosterone at 1-day or 1-week post-treatment compared to both pre-treatment baseline levels and control group levels. We conclude that acute dysregulation of the production of certain glucocorticoid precursor molecules was observed after a single treatment with a lipophilic statin drug. This may be of clinical relevance for individuals with underlying or subclinical adrenal insufficiency.

GDF15 Is Elevated in Conditions of Glucocorticoid Deficiency and Is Modulated by Glucocorticoid Replacement.

CONTEXT: GDF15 is a stress-induced hormone acting in the hindbrain that activates neural circuitry involved in establishing aversive responses and reducing food intake and body weight in animal models. Anorexia, weight loss, nausea and vomiting are common manifestations of glucocorticoid deficiency, and we hypothesized that glucocorticoid deficiency may be associated with elevated levels of GDF15. OBJECTIVE: To determine the impact of primary adrenal insufficiency (PAI) and glucocorticoid replacement on circulating GDF15 levels. METHODS AND RESULTS: We measured circulating concentrations of GDF15 in a cohort of healthy volunteers and Addison's disease patients following steroid withdrawal. Significantly higher GDF15 (mean ± standard deviation [SD]) was observed in the Addison's cohort, 739.1 ± 225.8 pg/mL compared to healthy controls, 497.9 ± 167.7 pg/mL (P = 0.01). The effect of hydrocortisone replacement on GDF15 was assessed in 3 independent PAI cohorts with classical congenital adrenal hyperplasia or Addison's disease; intravenous hydrocortisone replacement reduced GDF15 in all groups. We examined the response of GDF15 to increasing doses of glucocorticoid replacement in healthy volunteers with pharmacologically mediated cortisol deficiency. A dose-dependent difference in GDF15 (mean ± SD) was observed between the groups with values of 491.0 ± 157.7 pg/mL, 427.0 ± 152.1 pg/mL and 360 ± 143.1 pg/mL, in the low, medium and high glucocorticoid replacement groups, respectively, P < .0001. CONCLUSIONS: GDF15 is increased in states of glucocorticoid deficiency and restored by glucocorticoid replacement. Given the site of action of GDF15 in the hindbrain and its effects on appetite, further study is required to determine the effect of GDF15 in mediating the anorexia and nausea that is a common feature of glucocorticoid deficiency.

Partial Reconstitution of the Hypothalamo-Pituitary Axes After Pituitary Stalk Sectioning and Specific Magnetic Resonance Imaging Findings.

BACKGROUND: Pituitary stalk sectioning is only essential in cases of craniopharyngioma originating from the stalk or metastatic tumor to the stalk. Some patients can discontinue postoperative antidiuretic hormone (ADH) supplementation with special conditions. METHODS: Sixty-three patients with craniopharyngiomas who were treated by surgery with pituitary stalk sectioning were included in this study. Great care was taken to preserve the fine arteries running along the lateral walls of the third ventricle. Removal rates, change of endocrinologic status, and magnetic resonance imaging (MRI) findings were investigated. RESULTS: Total removal was achieved in 52 of 54 patients in initial surgery (96.3%), and in 5 of 9 patients in retreatment (55.6%). ADH supplementation was required in all patients from the day of surgery, but was discontinued in 29 of 54 patients among the initial surgery group (53.7%) and in 2 of 9 patients among the retreatment group (22.2%). Preservation of thyroid hormone secretion was observed in 24 of 31 patients who could discontinue ADH (77.4%), but only in 12 of 32 patients who could not discontinue ADH (37.5%). Recovery from diabetes insipidus (DI) was significantly associated with preservation of thyroid function (P < 0.01). Postoperative MRI showed that part of the hypothalamus was enhanced in patients with recovery from DI. CONCLUSIONS: Total removal was achieved in 91% of all cases. Half of the patients could discontinue ADH supplementation, which was associated with preservation of thyroid function. The findings of hypothalamic enhancement on postoperative MRI may be associated with recovery from DI.

ATP-binding cassette transporter G1 deficiency is associated with mild glucocorticoid insufficiency in mice.

OBJECTIVE: Since cholesterol is the sole precursor for glucocorticoid synthesis, it is hypothesized that genetic defects in proteins that impact the cellular cholesterol pool may underlie glucocorticoid insufficiency in humans. In the current study, we specifically focused on the cholesterol efflux mediator ATP-binding cassette transporter G1 (ABCG1) as gene candidate. METHODS: The adrenal transcriptional response to fasting stress was measured in wild-type mice to identify putative novel gene candidates. Subsequently, the adrenal glucocorticoid function was compared between ABCG1 knockout mice and wild-type controls. RESULTS: Overnight food deprivation induced a change in relative mRNA expression levels of cholesterol metabolism-related proteins previously linked to steroidogenesis, i.e. scavenger receptor class B type I (+149%; P < 0.001), LDL receptor (-70%; P < 0.001) and apolipoprotein E (-41%; P < 0.01). Strikingly, ABCG1 transcript levels were also markedly decreased (-61%; P < 0.05). In contrast to our hypothesis that decreasing cholesterol efflux would increase the adrenal cholesterol pool and enhance glucocorticoid output, ABCG1 knockout mice as compared to wild-type mice exhibited a reduced ability to secrete corticosterone in response to an ACTH challenge (two-way ANOVA: P < 0.001 for genotype) or fasting stress. As a result, glucocorticoid target gene expression levels in liver and hypothalamus were reduced and blood lymphocyte concentrations and spleen weights increased in ABCG1 knockout mice under fasting stress conditions. This was paralleled by a 48% reduction in adrenal cholesteryl ester stores and stimulation of adrenal NPC intracellular cholesterol transporter 2 (+37%; P < 0.05) and apolipoprotein E (+59%; P < 0.01) mRNA expression. CONCLUSION: ABCG1 deficiency is associated with mild glucocorticoid insufficiency in mice.

Hyponatremia and Glucocorticoid Deficiency.

Hyponatremia is the commonest electrolyte deficiency in clinical practice. Of the many causes of hyponatremia, syndrome of inappropriate antidiuresis (SIAD) is the commonest. Glucocorticoid deficiency, due to central/secondary adrenal insufficiency, is the key differential diagnosis for SIAD, as it presents with a similar biochemical picture of euvolemic hyponatremia and inappropriate urinary concentration. The underlying mechanisms for the development of hyponatremia in glucocorticoid deficiency are: (1) impaired renal water handling in the absence of circulating cortisol and (2) increased plasma concentrations of arginine vasopressin (AVP), despite hypo-osmolality. The original diagnostic criteria for SIAD emphasized that normal adrenal reserve was essential for its diagnosis, in recognition of the similar biochemical presentation of SIAD and glucocorticoid deficiency. This has been emphasized in all of the recently published clinical guidelines. However, data from the literature suggest that clinicians ignore the measurement of plasma cortisol concentration in both clinical practice and research protocols. The reported prevalence of glucocorticoid deficiency in patients presenting with euvolemic hyponatremia may, therefore, be underestimated and patients with a dangerous, but treatable cause of hyponatremia are inevitably missed. In this chapter, we will review the physiopathology of hyponatremia in the setting of glucocorticoid deficiency. We will discuss the differential diagnosis of euvolemic hyponatremia and review the prevalence of glucocorticoid deficiency in patients with hyponatremia.

A novel de novo frameshift mutation in NR0B1 and low prenatal estriol in adrenal hypoplasia congenita.

Mutations in the gene NR0B1 have been associated with several clinical phenotypes of X-linked adrenal hypoplasia congenita (AHC). The degree and onset of adrenal insufficiency and involvement of hypogonadotropic hypogonadism is variable and may not be concordant with the identified mutation. We review a patient with AHC in which prenatal estriol levels were low, presenting with early-onset mineralocorticoid deficiency in the newborn period followed by glucocorticoid deficiency 2 years later. The reported child is hemizygous for a novel mutation that is deemed de novo in the ligand-binding site of the protein (DAX1) expressed by NR0B1. The identified frameshift mutation results in a T407N/fs protein change. Low prenatal estriol levels may represent a sensitive marker of potentially fatal disorders associated with adrenal insufficiency and should be utilized more frequently. Additionally, accurate reporting of mutations in NR0B1 and the associated phenotype are important to eventually establish a genotype-phenotype correlation that may help anticipate guidance in AHC.

News about the genetics of congenital primary adrenal insufficiency.

Primary adrenal insufficiency (PAI) is characterized by impaired production of steroid hormones due to an adrenal cortex defect. This condition incurs a risk of acute insufficiency which may be life-threatening. Today, 80% of pediatric forms of PAI have a genetic origin but 5% have no clear genetic support. Recently discovered mutations in genes relating to oxidative stress have opened the way to research on genes unrelated to the adrenal gland. Identification of causal mutations in a gene responsible for PAI allows genetic counseling, guidance of follow-up and prevention of complications. This is particularly true for stress oxidative anomalies, as extra-adrenal manifestations may occur due to the sensitivity to oxidative stress of other organs such as the heart, thyroid, liver, kidney and pancreas.

Triple-A syndrome: a wide spectrum of adrenal dysfunction.

OBJECTIVE: Triple-A or Allgrove syndrome is an autosomal recessive disorder due to mutations in the AAAS gene, which encodes a nucleoporin named ALADIN. It is characterized by a classical clinical triad: alacrima, achalasia and adrenal insufficiency, the canonic symptoms that are associated with progressive peripheral neuropathy. Only a few cohorts have been reported. The objective of the present study was to characterize the various spectra of adrenal function in Triple-A patients. METHODS: A retrospective clinical and biological monitoring of 14 patients (10 families) was done in a single multidisciplinary French center. All had AAAS gene sequenced and adrenal function evaluation. RESULTS: Nine different AAAS mutations were found, including one new mutation: c.755G>C, p.(Trp252Ser). Regarding adrenal function, defects of the zona fasciculata and reticularis were demonstrated by increased basal ACTH levels and low DHEAS levels in all cases regardless of the degree of glucocorticoid deficiency. In contrast, mineralocorticoid function was always conserved: i.e., normal plasma renin level associated with normal aldosterone level. The main prognostic feature was exacerbation of neuropathy and cognitive disorders. CONCLUSIONS: These data suggest that, in Triple-A patients, adrenal function can be deficient, insufficient or compensated. In our cohort after the first decade of life, there does not appear to be any degradation of adrenal function over time. However, patients with compensated adrenal function should be informed and educated to manage a glucocorticoid replacement therapy in case of stressful conditions, with no need for systematic long-term treatment.

Group 1. Epidemiology of primary and secondary adrenal insufficiency: Prevalence and incidence, acute adrenal insufficiency, long-term morbidity and mortality.

The prevalence of primary adrenal insufficiency is estimated at between 82-144/million, with auto-immunity being the most common cause in adults and genetic causes, especially enzyme defects, being the most common cause in children. The prevalence of secondary adrenal deficiency is estimated to be between 150-280/million. The most frequent occurrence is believed to be corticosteroid-induced insufficiency, despite the incidence of clinically relevant deficiency after cessation of glucocorticoid treatment being widely debated. Data on mortality in adrenal insufficiency are contradictory, with studies from Sweden suggesting a two-fold increase in comparison to the general population, but this is not consistently reported in all studies. However, increased mortality has been consistently reported in young patients, associated with infection and/or acute adrenal insufficiency. Acute adrenal deficiency (adrenal crisis) occurs in primary as well as secondary adrenal insufficiency. Its incidence, mostly determined in retrospective studies, is estimated in Europe at 6-8/100 patients/year. A prospective study reported 0.5 deaths/100 patient-years from adrenal crisis. Long-term morbidity of adrenal insufficiency is not well-established, the increased cardiovascular risk or bone demineralization which are not consistently reported may also be due to a supraphysiological glucocorticoid replacement therapy. However, alteration in quality of life, both in physical and mental health components, has been demonstrated by several studies in both primary and secondary adrenal insufficiency.

The unresolved riddle of glucocorticoid withdrawal.

Glucocorticoid (GC) therapy is the most common cause of adrenal insufficiency (AI). The real prevalence of AI after GC is unknown but it could involve more than 30% of patients. Some gene variation has been associated with the variability of hypothalamic-pituitary-adrenal (HPA) axis and this issue could contribute to the individual variation of adrenal function after GC treatment. Symptoms and signs of AI are nonspecific and frequently the diagnosis is delayed. Dosage, duration of treatment, administration route and serum cortisol value are not completely useful to predict AI. Clinical estimation of HPA suppression is difficult and biochemical testing is needed to confirm the diagnosis of AI. The different tapering regimens are based on a very low quality of evidence and considering the sizable individual variation, it is improbable that future research will find a secure GC tapering schedule for all patients. The aim of this review is to address the most important aspects in management of GC withdrawal in light of current knowledge.

Subchronic glucocorticoids, glutathione depletion and a postpartum model elevate monoamine oxidase a activity in the prefrontal cortex of rats.

Recent human brain imaging studies implicate dysregulation of monoamine oxidase-A (MAO-A), in particular in the prefrontal cortex (PFC) and anterior cingulate cortex (ACC), in the development of major depressive disorder (MDD). This study investigates the influence of four alterations underlying important pathologies of MDD, namely, chronic elevation of glucocorticoid levels, glutathione depletion, changes in female gonadal sex hormones and serotonin concentration fluctuation, on MAO-A and MAO-B activities in rats. Young adult rats exposed chronically to the synthetic glucocorticoid dexamethasone at 0, 0.05, 0.5, and 2.0mg/kg/day (osmotic minipumps) for eight days showed significant dose-dependent increases in activities of MAO-A in PFC (+17%, p<0.001) and ACC (+9%, p<0.01) and MAO-B in PFC (+14%, p<0.001) and increased serotonin turnover in the PFC (+31%, p<0.01), not accounted for by dexamethasone-induced changes in serotonin levels, since neither serotonin depletion nor supplementation affected MAO-A activity. Sub-acute depletion of the major antioxidant glutathione by diethyl maleate (5mmol/kg, i.p.) for three days, which resulted in a 36% loss of glutathione in PFC (p=0.0005), modestly, but significantly, elevated activities of MAO-A in PFC and MAO-B in PFC, ACC and hippocampus (+6-9%, p<0.05). Changes in estrogen and progesterone representing pseudopregnancy were associated with significantly elevated MAO-A activity in the ACC day 4-7 postpartum (10-18%, p<0.05 to p<0.0001) but not the PFC or hippocampus. Hence, our study provides data in support of strategies targeting glucocorticoid and glutathione systems, as well as changes in female sex hormones for normalization of MAO-A activities and thus treatment of mood disorders.

Glucocorticoid-deficient hypoadrenocorticism secondary to intravascular lymphoma in the adrenal glands of a dog.

CASE REPORT: A 2-year-old neutered male German Shepherd dog was presented with weakness, poor appetite and weight loss. Glucocorticoid-deficient hypoadrenocorticism was diagnosed with undetectable pre- and post-ACTH cortisol concentrations but normal sodium and potassium concentrations. Despite appropriate supplementation with glucocorticoids, the patient's weakness progressed and neurological deficits developed. The patient was euthanased. Histopathological analysis of multiple organs, including the adrenal glands, showed an accumulation of neoplastic lymphocytes within blood vessels, consistent with a diagnosis of intravascular lymphoma. Histologically, in both adrenal glands, the architecture of the zona fasciculata and reticularis was disrupted by blood vessels congested with a neoplastic population of T-lymphocytes; the zona glomerulosa remained intact. CONCLUSION: This is the first report of intravascular lymphoma causing glucocorticoid-deficient hypoadrenocorticism in a dog.

Extensive Regulation of Diurnal Transcription and Metabolism by Glucocorticoids.

Altered daily patterns of hormone action are suspected to contribute to metabolic disease. It is poorly understood how the adrenal glucocorticoid hormones contribute to the coordination of daily global patterns of transcription and metabolism. Here, we examined diurnal metabolite and transcriptome patterns in a zebrafish glucocorticoid deficiency model by RNA-Seq, NMR spectroscopy and liquid chromatography-based methods. We observed dysregulation of metabolic pathways including glutaminolysis, the citrate and urea cycles and glyoxylate detoxification. Constant, non-rhythmic glucocorticoid treatment rescued many of these changes, with some notable exceptions among the amino acid related pathways. Surprisingly, the non-rhythmic glucocorticoid treatment rescued almost half of the entire dysregulated diurnal transcriptome patterns. A combination of E-box and glucocorticoid response elements is enriched in the rescued genes. This simple enhancer element combination is sufficient to drive rhythmic circadian reporter gene expression under non-rhythmic glucocorticoid exposure, revealing a permissive function for the hormones in glucocorticoid-dependent circadian transcription. Our work highlights metabolic pathways potentially contributing to morbidity in patients with glucocorticoid deficiency, even under glucocorticoid replacement therapy. Moreover, we provide mechanistic insight into the interaction between the circadian clock and glucocorticoids in the transcriptional regulation of metabolism.

Non-Virilizing Congenital Adrenal Hyperplasia in a Female Patient with a Novel HSD3B2 Mutation.

Classic 3ß-hydroxysteroid dehydrogenase type 2 (3ß-HSD II) deficiency causes congenital adrenal hyperplasia with glucocorticoid, mineralocorticoid, and sex steroid deficiency. We present a female patient with congenital adrenal hyperplasia detected in newborn screening due to elevated 17OH-progesterone. Female external genitalia and non-measurable androgen levels elicited the suspicion of a defect early in the steroid cascade. Two loss-of-function HSD3B2 mutations (1 novel) were detected and confirmed in silico. We argue that in a girl with glucocorticoid and mineralocorticoid deficiency without virilization, 3ß-HSD II deficiency is an important differential diagnosis. 17OH-progesterone may initially be elevated due to placental and peripheral activity of 3ß-HSD I, whereas dehydroepiandrosterone may not be increased.

Recent Advances in Hydrocortisone Replacement Treatment.

Since the first use of cortisone in patients around 65 years ago, the use of synthetic glucocorticoids has made a crucial impact on the treatment of several diseases in medicine. Although significant reductions in morbidity and mortality have occurred in patients suffering from cortisol deficiency, conventional hydrocortisone replacement treatment is still inadequate. A major limitation is that it fails to replace cortisol in a physiological manner. Cortisol has a distinct circadian rhythm and acts as a secondary messenger synchronizing the central to peripheral clocks, hence playing a key role in biological processes and the circadian timing system. Circadian misalignment has been associated with ill-health and so nonphysiological glucocorticoid treatment could explain the increased mortality rate, poor quality of life and metabolic complications in patients suffering from adrenal insufficiency. Attempts at replacing cortisol in a physiological manner have shown significant progress in the past decade with the development of modified-release formulations of hydrocortisone (Chronocort® and Plenadren®) and continuous subcutaneous hydrocortisone infusions. Initial studies investigating the use of these replacement regimens are promising, demonstrating both clinical and biochemical improvement. Larger studies are needed to determine whether this novel approach enhances long-term outcomes in both children and adults with cortisol deficiency. This is a work of the U.S. Government and is not subject to copyright protection in the United States. Foreign copyrights may apply. Published by S. Karger AG, Basel.