Steroid profiling in adrenal disease

The measurement of steroid hormones in blood and urine, which reflects steroid biosynthesis and metabolism, has been recognized as a valuable tool for identifying and distinguishing steroidogenic disorders. The application of mass spectrometry enables the reliable and simultaneous analysis of large panels of steroids, ushering in a new era for diagnosing adrenal diseases. However, the interpretation of complex hormone results necessitates the expertise and experience of skilled clinicians. In this scenario, machine learning techniques are gaining worldwide attention within healthcare fields. The clinical values of combining mass spectrometry-based steroid profiles analysis with machine learning models, also known as steroid metabolomics, have been investigated for identifying and discriminating adrenal disorders such as adrenocortical carcinomas, adrenocortical adenomas, and congenital adrenal hyperplasia. This promising approach is expected to lead to enhanced clinical decision-making in the field of adrenal diseases. This review will focus on the clinical performances of steroid profiling, which is measured using mass spectrometry and analyzed by machine learning techniques, in the realm of decision-making for adrenal diseases.

β-catenin in adrenal zonation and disease

The Wnt signaling pathway is a critical mediator of the development and maintenance of several tissues. The adrenal cortex is highly dependent upon Wnt/β-catenin signaling for proper zonation and endocrine function. Adrenocortical cells emerge in the peripheral capsule and subcapsular cortex of the gland as progenitor cells that centripetally differentiate into steroid hormone-producing cells of three functionally distinct concentric zones that respond robustly to various endocrine stimuli. Wnt/β-catenin signaling mediates adrenocortical progenitor cell fate and tissue renewal to maintain the gland throughout life. Aberrant Wnt/β-catenin signaling contributes to various adrenal disorders of steroid production and growth that range from hypofunction and hypoplasia to hyperfunction, hyperplasia, benign adrenocortical adenomas, and malignant adrenocortical carcinomas. Great strides have been made in defining the molecular underpinnings of adrenocortical homeostasis and disease, including the interplay between the capsule and cortex, critical components involved in maintaining the adrenocortical Wnt/β-catenin signaling gradient, and new targets in adrenal cancer. This review seeks to examine these and other recent advancements in understanding adrenocortical Wnt/β-catenin signaling and how this knowledge can inform therapeutic options for adrenal disease.

Fixing the broken clock in adrenal disorders: focus on glucocorticoids and chronotherapy

The circadian rhythm derives from the integration of many signals that shape the expression of clock-related genes in a 24-h cycle. Biological tasks, including cell proliferation, differentiation, energy storage, and immune regulation, are preferentially confined to specific periods. A gating system, supervised by the central and peripheral clocks, coordinates the endogenous and exogenous signals and prepares for transition to activities confined to periods of light or darkness. The fluctuations of cortisol and its receptor are crucial in modulating these signals. Glucocorticoids and the autonomous nervous system act as a bridge between the suprachiasmatic master clock and almost all peripheral clocks. Additional peripheral synchronizing mechanisms including metabolic fluxes and cytokines stabilize the network. The pacemaker is amplified by peaks and troughs in cortisol and their response to food, activity, and inflammation. However, when the glucocorticoid exposure pattern becomes chronically flattened at high- (as in Cushing's syndrome) or low (as in adrenal insufficiency) levels, the system fails. While endocrinologists are well aware of cortisol rhythm, too little attention has been given to interventions aimed at restoring physiological cortisol fluctuations in adrenal disorders. However, acting on glucocorticoid levels may not be the only way to restore clock-related activities. First, a counterregulatory mechanism on the glucocorticoid receptor itself controls signal transduction, and second, melatonin and/or metabolically active drugs and nutrients could also be used to modulate the clock. All these aspects are described herein, providing some insights into the emerging role of chronopharmacology, focusing on glucocorticoid excess and deficiency disorders.

Cardiomyopathies and Adrenal Diseases

Cardiomyopathies are myocardial disorders in which heart muscle is structurally and/or functionally abnormal. Previously, structural cardiomyocyte disorders due to adrenal diseases, such as hyperaldosteronism, hypercortisolism, and hypercatecholaminism, were misunderstood, and endomyocardial biopsy (EMB) was not performed because was considered dangerous and too invasive. Recent data confirm that, if performed in experienced centers, EMB is a safe technique and gives precious information about physiopathological processes implied in clinical abnormalities in patients with different systemic disturbances. In this review, we illustrate the most important features in patients affected by primary aldosteronism (PA), Cushing's syndrome (CS), and pheochromocytoma (PHEO). Then, we critically describe microscopic and ultrastructural aspects that have emerged from the newest EMB studies. In PA, the autonomous hypersecretion of aldosterone induces the alteration of ion and water homeostasis, intracellular vacuolization, and swelling; interstitial oedema could be a peculiar feature of myocardial toxicity. In CS, cardiomyocyte hypertrophy and myofibrillolysis could be related to higher expression of atrogin-1. Finally, in PHEO, the hypercontraction of myofilaments with the formation of contraction bands and occasional cellular necrosis has been observed. We expect to clear the role of EMB in patients with cardiomyopathies and adrenal disease, and we believe EMB is a valid tool to implement new management and therapies.

Steroid Metabolome Analysis in Disorders of Adrenal Steroid Biosynthesis and Metabolism

Steroid biosynthesis and metabolism are reflected by the serum steroid metabolome and, in even more detail, by the 24-hour urine steroid metabolome, which can provide unique insights into alterations of steroid flow and output indicative of underlying conditions. Mass spectrometry-based steroid metabolome profiling has allowed for the identification of unique multisteroid signatures associated with disorders of steroid biosynthesis and metabolism that can be used for personalized approaches to diagnosis, differential diagnosis, and prognostic prediction. Additionally, steroid metabolome analysis has been used successfully as a discovery tool, for the identification of novel steroidogenic disorders and pathways as well as revealing insights into the pathophysiology of adrenal disease. Increased availability and technological advances in mass spectrometry-based methodologies have refocused attention on steroid metabolome profiling and facilitated the development of high-throughput steroid profiling methods soon to reach clinical practice. Furthermore, steroid metabolomics, the combination of mass spectrometry-based steroid analysis with machine learning-based approaches, has facilitated the development of powerful customized diagnostic approaches. In this review, we provide a comprehensive up-to-date overview of the utility of steroid metabolome analysis for the diagnosis and management of inborn disorders of steroidogenesis and autonomous adrenal steroid excess in the context of adrenal tumors.

Steroid biomarkers in human adrenal disease

Adrenal steroidogenesis is a robust process, involving a series of enzymatic reactions that facilitate conversion of cholesterol into biologically active steroid hormones under the stimulation of angiotensin II, adrenocorticotropic hormone and other regulators. The biosynthesis of mineralocorticoids, glucocorticoids, and adrenal-derived androgens occur in separate adrenocortical zones as a result of the segregated expression of steroidogenic enzymes and cofactors. This mini review provides the principles of adrenal steroidogenesis, including the classic and under-appreciated 11-oxygenated androgen pathways. Several adrenal diseases result from dysregulated adrenal steroid synthesis. Herein, we review growing evidence that adrenal diseases exhibit characteristic modifications from normal adrenal steroid pathways that provide opportunities for the discovery of biomarker steroids that would improve diagnosis and monitoring of adrenal disorders.

High Risk of Malignancy in Patients with Incidentally Discovered Adrenal Masses: Accuracy of Adrenal Imaging and Image-Guided Fine-Needle Aspiration Cytology

Aims and background

The incidental finding of nonfunctioning adrenal masses (incidentalomas) is common, but no reliable criteria in differentiating between benign and malignant adrenal masses have been defined. The aim of this preliminary study was to assess the usefulness of adrenal imaging and image-guided fine-needle aspiration cytology in patients with nonfunctioning adrenal incidentalomas with the aim of excluding or confirming malignancy before surgery.

Methods

Forty-two consecutive patients (18 men and 24 women; median age, 54 years; range, 25-75 years) with incidentally discovered adrenal masses of 3 cm or more in the greatest diameter were prospectively enrolled in the study. All patients underwent helical computerized tomography scan and image-guided fine-needle aspiration cytology, 33 (78.6%) underwent magnetic resonance imaging, and 26 (61.9%) underwent norcholesterol scintigraphy before adrenalectomy.

Results

The revised final pathology showed 30 (71.4%) benign (26 adrenocortical adenomas, of which 3 were atypical, 2 ganglioneuromas, and 2 nonfunctioning benign pheochromocytomas) and 12 (28.6%, 95% CI = 15-42) adrenal malignancies (8 adrenocortical carcinomas and 4 unsuspected adrenal metastases). The definitive diagnosis of adrenocortical carcinoma was made according to Weiss criteria and confirmed on the basis of local invasion at surgery or metastases. The sensitivity, specificity and accuracy were 75%, 67% and 83% for computerized tomography scan, 92%, 95% and 94% for magnetic resonance imaging, 89%, 94% and 92% for norcholesterol scintigraphy, and 92%, 100% and 98% for fine-needle aspiration cytology. The sensitivity and accuracy of image-guided fine-needle aspiration cytology and magnetic resonance imaging together reached 100%. Immediate periprocedural complications of fine-needle aspiration cytology occurred in 2 (4.7%) patients: self-limited pneumothorax (n = 1), and severe pain (n = 1) requiring analgesic therapy. No postprocedural or late complications were observed.

Conclusions

With the aim of selecting for surgery patients with a non-functioning adrenal incidentaloma of 3 cm or more in diameter, the combination of magnetic resonance imaging and fine-needle aspiration cytology should be considered the strategy of choice.

Adolescent Inhalant Abuse Results in Adrenal Dysfunction and a Hypermetabolic Phenotype with Persistent Growth Impairments

BACKGROUND/AIMS

Abuse of toluene products (e.g., glue-sniffing) primarily occurs during adolescence and has been associated with appetite suppression and weight impairments. However, the metabolic phenotype arising from adolescent inhalant abuse has never been fully characterised, and its persistence during abstinence and underlying mechanisms remain unknown.

METHODS

Adolescent male Wistar rats (post-natal day 27) were exposed to inhaled toluene (10,000 ppm) (n = 32) or air (n = 48) for 1 h/day, 3 days/week for 4 weeks, followed by 4 weeks of abstinence. Twenty air rats were pair-fed to the toluene group, to differentiate the direct effects of toluene from under-nutrition. Food intake, weight, and growth were monitored. Metabolic hormones were measured after exposure and abstinence periods. Energy expenditure was measured using indirect calorimetry. Adrenal function was assessed using adrenal histology and hormone testing.

RESULTS

Inhalant abuse suppressed appetite and increased energy expenditure. Reduced weight gain and growth were observed in both the toluene and pair-fed groups. Compared to the pair-fed group, and despite normalisation of food intake, the suppression of weight and growth for toluene-exposed rats persisted during abstinence. After exposure, toluene-exposed rats had low fasting blood glucose and insulin compared to the air and pair-fed groups. Consistent with adrenal insufficiency, adrenal hypertrophy and increased basal adrenocorticotropic hormone were observed in the toluene-exposed rats, despite normal basal corticosterone levels.

CONCLUSIONS

Inhalant abuse results in negative energy balance, persistent growth impairment, and endocrine changes suggestive of adrenal insufficiency. We conclude that adrenal insufficiency contributes to the negative energy balance phenotype, potentially presenting a significant additional health risk for inhalant users.

The adrenal gland microenvironment in health, disease and during regeneration

The adrenal gland is a key component of the stress system in the human body. Multiple direct and paracrine interactions between different cell types and their progenitors take place within the adrenal gland microenvironment. These unique interactions are supported by high vascularization and the adrenal cortex extracellular matrix. Alterations in the adrenal gland microenvironment are known to influence the progression of several pathological conditions, such as obesity and sepsis, and to be influenced by these disorders. For example, it has been suggested that activation of immune-adrenal crosstalk during sepsis induces elevated adrenal glucocorticoid levels, whereas crosstalk between adrenocortical cells and sonic hedgehog responsive stem cells was found to contribute to the increased size of the adrenal cortex during obesity. By contrast to sepsis, where activation of adrenal glucocorticoid production has protective effects, chronic exposure to high levels of glucocorticoids induces adverse effects, typically manifested in patients with Cushing syndrome, such as increased body weight, dyslipidemia, glucose intolerance, and hypertension. Therefore, a better understanding of factors involved in the regulation of the adrenal gland microenvironment is crucial. This review highlights bidirectional interactions occurring between the adrenal gland microenvironment and systemic responses during obesity and sepsis. Furthermore, it presents and discusses recent advancements and challenges in attempts to restore or regenerate adrenal gland function, including the use of oxygenated immune-isolating devices.

l-Lysine Acts as a Serotonin Type 4 Receptor Antagonist to Counteract In Vitro and In Vivo the Stimulatory Effect of Serotonergic Agents on Aldosterone Secretion in Man

In the normal human adrenal gland, serotonin (5-HT) stimulates aldosterone secretion through the 5-HT₄ receptor (5-HT4R). However, the physiological role of the serotonergic control of adrenocortical function is not known. In the present study, we have investigated the ability of l-Lysine, which has been shown to act as a 5-HT₄ receptor antagonist, to counteract in vitro and in vivo the stimulatory effect of 5-HT4R agonists on aldosterone production. l-Lysine was found to inhibit aldosterone production induced by 5-HT and the 5-HT4R agonists BIMU8 from cultured human adrenocortical cells. The action of l-Lysine (4.95 g/day orally) on the adrenal cortex was also evaluated in 20 healthy volunteers in a double blind, cross-over, placebo controlled study. l-Lysine had no significant influence on basal plasma aldosterone levels and the aldosterone responses to upright posture, tetracosactide, and low sodium diet (10 mmol/day for 3 days). Conversely, l-Lysine significantly reduced the surge of plasma aldosterone induced by metoclopramide indicating that l-Lysine is able to efficiently antagonize the adrenal 5-HT₄ receptors in vivo. These results suggest that l-Lysine supplementation may represent a new treatment of primary adrenal diseases in which corticosteroid hypersecretion is driven by overexpressed 5-HT₄ receptors.

Non-Tumor Cystic Lesions of the Adrenal Gland

Adrenal cystic lesions are uncommon but due to the improved radiologic imaging techniques their appearance seems to increase.

MATERIAL AND METHODS

We analyzed the clinical and radiological findings of 10 patients with adrenal cysts and the pathological features of the operative material. Standard dissection procedure and paraffin embedded tissue sections were made, stained by HE and immunohistochemically with CD34, CD 31, Factor 8, Podoplanin, CKWS and AE1/AE3 RESULTS: The mean age of the patients was 40.6 years; female to male ratio was 2.3:1. All the cysts were diagnosed as cystic lesions radiologically except one. The most present clinical symptom was abdominal pain. The diameter of the cysts measured from 2 to 7 cm. Four of the cysts were diagnosed as pseudocysts and six as endothelial. Six cysts were lined by CD34(+) and CD31(+) cells, four were lined by Factor 8(+) and podoplanin(+) cells and four had no lining.

CONCLUSION

Endothelial cysts were more common cysts in our study and the immunohistochemical results suggested common vascular origin to all endothelial cysts and supported additional separation of angiomatous and lymphangiomathous adrenal vascular cysts.

Increased Hair Cortisol Concentrations and BMI in Patients With Pituitary-Adrenal Disease on Hydrocortisone Replacement

CONTEXT

Intrinsic imperfections and lack of reliable biomarkers preclude optimal individual dosing of hydrocortisone replacement in adrenal insufficiency (AI). However, the clinical relevance of optimal dosing is exemplified by frequently occurring side effects of overreplacement and the dangers of underreplacement. Cortisol in scalp hair has been identified as a retrospective biomarker for long-term cortisol exposure. We compared hair cortisol concentrations (CORT(hair)) of patients with primary or secondary AI on replacement therapy with those of patient controls with a pituitary disease without AI (PCs) and of healthy controls (HCs).

METHODS

In this cross-sectional study, hair samples and anthropometric data were collected in 132 AI patients (52 males), 42 PCs (11 males), and 195 HCs (90 males). The proximal 3 cm of hair were used. CORT(hair) were measured using an ELISA.

RESULTS

CORT(hair) were higher in AI patients than in HCs and PCs (P < .001), and hydrocortisone dose correlated with CORT(hair) (P = .04). Male AI patients demonstrated higher CORT(hair) than female patients (P < .001). AI patients had higher body mass index (BMI) than HCs (P < .001), and BMI correlated with CORT(hair) in the whole sample (P < .001).

CONCLUSION

Physiological hydrocortisone replacement is associated with increased CORT(hair). The association between CORT(hair) and BMI could suggest a mild overtreatment that may lead to adverse anthropomorphic side effects, especially in males. CORT(hair) measurements may be a promising additional tool to monitor cumulative hydrocortisone replacement in AI.

Metabolic and anatomic characteristics of benign and malignant adrenal masses on positron emission tomography/computed tomography: a review of literature

PET/CT with (18)F-fluorodeoxyglucose (FDG) or using different radiocompounds has proven accuracy for detection of adrenal metastases in patients undergoing cancer staging. It can assist the diagnostic work-up in oncology patients by identifying distant metastases to the adrenal(s) and defining oligometastatic disease that may benefit from targeted intervention. In patients with incidentally discovered adrenal nodules, so-called adrenal "incidentaloma" FDG PET/CT is emerging as a useful test to distinguish benign from malignant etiology. Current published evidence suggests a role for FDG PET/CT in assessing the malignant potential of an adrenal lesion that has been 'indeterminately' categorized with unenhanced CT, adrenal protocol contrast-enhanced CT, or chemical-shift MRI. FDG PET/CT could be used to stratify patients with higher risk of malignancy for surgical intervention, while recommending surveillance for adrenal masses with low malignant potential. There are caveats for interpretation of the metabolic activity of an adrenal nodule on PET/CT that may lead to false-positive and false-negative interpretation. Adrenal lesions represent a wide spectrum of etiologies, and the typical appearances on PET/CT are still being described, therefore our goal was to summarize the current diagnostic strategies for evaluation of adrenal lesions and present metabolic and anatomic appearances of common and uncommon adrenal lesions. In spite of the emerging role of PET/CT to differentiate benign from malignant adrenal mass, especially in difficult cases, it should be emphasized that PET/CT is not needed for most patients and that many diagnostic problems can be resolved by CT and/or MR imaging.

From β-catenin to ARM-repeat proteins in adrenocortical disorders

Armadillo-containing proteins (ACPs) are a large family of evolutionary conserved proteins, characterized by the tandem repeat copy of a 42 amino acids motif, which forms a 3 dimensional protein-protein interaction domain. This permits ACPs to interact with plenty of partners and consequently, most of these proteins have several independent cellular roles. Perhaps the most well-known protein of this family is β-catenin, which is crucial in the regulation of development and adult tissue homeostasis through its 2 independent functions, acting in cellular adhesion in addition to being a transcriptional co-activator. APCs have important functions in many tissues, but here we summarize the adrenocortical role of 2 well-described ACPs, β-catenin (CTNNB1), Adenomatous Polyposis Coli (APC), and discuss the possible role in the adrenal cortex of the most recently discovered, Armadillo-repeat containing 5 (ARMC5).

Mass spectrometry theory and application to adrenal diseases

The diagnosis and management of adrenal diseases hinge upon accurate determination of hormone concentrations in blood and other body fluids. The advent of immunoassays for various steroid hormones has enabled the remarkable progress in adrenal disease over the last several decades, with some limitation. Sequential immunoassay of single analytes is a tedious process, which requires aliquots for each assay. In many complex adrenal diseases, including adrenal cancer and congenital adrenal hyperplasia, the patterns or ratios of multiple steroids rather than the value of any one steroid is more relevant. Although gas chromatography/mass spectrometry of urinary steroid metabolites has been employed to profile steroid production, throughput is slow, and availability is sparse. Recent generations of liquid chromatography-tandem mass spectrometry instruments (LC-MS/MS) provide the throughput and sensitivity required to measure many steroids simultaneously using small samples for commercial and research uses. Even in the best hands, however, LC-MS/MS suffers from limitations and requires diligent attention to detail during method development and implementation. This article reviews the theory, instrumentation principles and terminology, and practical application of mass spectrometry to clinical adrenal disorders.

Adrenal disorders in pregnancy

Pregnancy is marked by alterations in a number of endocrine systems, including activation of the renin-angiotensin-aldosterone system and the hypothalamic-pituitary-adrenal axis. The placenta, the fetal adrenal glands and the liver constitute an interactive endocrine entity, known as the fetoplacental unit. In the fetoplacental unit, the fetal adrenal glands are the primary source of dehydroepiandrosterone sulphate, which is further metabolized by the fetal liver and placenta to produce a variety of oestrogens. Several disorders can affect both the fetal and maternal adrenal glands during pregnancy. The most common fetal adrenal disorder, steroid 21-hydroxylase deficiency, leads to abnormalities in sexual development and can be life threatening for the neonate. Although rare, maternal adrenal disorders are associated with considerable maternal mortality and morbidity if not promptly recognized and treated. However, diagnosis is often difficult to establish because of the endocrine changes occurring during normal pregnancies and the lack of reference values for the majority of the adrenal steroids. This Review provides an overview of adrenal steroid metabolism during pregnancy and focuses on diagnosis and treatment of the most common fetal and maternal adrenal disorders.

Prevention of CCl(4)-induced oxidative damage in adrenal gland by Digera muricata extract in rat

Digera muricata (L.) Mart. is a weed and commonly found in waste places, road sides and in maize fields during the summer season. It possesses antioxidant capacity and is locally used for various disorders such as inflammation, urination, as refrigerant, aperient and in sexual anomalies. In this study antioxidant potential of Digera muricata methanol extract (DMME) and n-hexane extract (DMHE) was evaluated against CCl(4)-induced oxidative stress in adrenal gland of Sprague-Dawley male rats. 42 rats were equally divided into 7 groups of 6 rats in each. Group I remained untreated, while Group II treated with vehicles. Group III received only CCl(4) (1 ml/kg b.w., 10% in olive oil) once a week for 16 weeks. Group IV and VI received DMME and DMHE at a dose of 200 mg/kg b.w. along with CCl(4). Animals of Group V and VII administered with DMME and DMHE alone at a dose of 200 mg/kg b.w. once a week for 16 weeks. Lipid peroxidation significantly increased while activities of antioxidant enzymes (CAT, SOD, GST, GSR and GSH-Px) were reduced in adrenal gland samples by the administration of CCl(4). Glutathione (GSH) concentration was significantly decreased whereas DNA fragmentation% and AgNORs count was increased in adrenal gland by CCl(4) administration. Treatment of rat by both the extracts (DMME, DMHE) and CCl(4) increased the glutathione level and activities of antioxidant enzymes while reduced the lipid peroxidation, DNA fragmentation percent and AgNORs count in adrenal gland. These results indicate that Digera muricata extract is able to ameliorate oxidative stress in adrenal gland induced by CCl(4) in rat.

Carney complex and other conditions associated with micronodular adrenal hyperplasias

Carney complex (CNC) is a multiple neoplasia syndrome that is inherited in an autosomal dominant manner and is characterized by skin tumors and pigmented lesions, myxomas, schwannomas, and various endocrine tumors. Inactivating mutations of the PRKAR1A gene coding for the regulatory type I-α (RIα) subunit of protein kinase A (PKA) are responsible for the disease in most CNC patients. The overall penetrance of CNC among PRKAR1A mutation carriers is near 98%. Most PRKAR1A mutations result in premature stop codon generation and lead to nonsense-mediated mRNA decay. CNC is genetically and clinically heterogeneous, with specific mutations providing some genotype-phenotype correlation. Phosphodiesterase-11A (the PDE11A gene) and -8B (the PDE8B gene) mutations were found in patients with isolated adrenal hyperplasia and Cushing syndrome, as well in patients with PPNAD. Recent evidences demonstrated that dysregulation of cAMP/PKA pathway can modulate other signaling pathways and contributes to adrenocortical tumorigenesis.

Aberrant expression of multiple hormone receptors in ACTH-independent macronodular adrenal hyperplasia causing Cushing's syndrome

OBJECTIVE

Aberrant adrenal expression of various hormone receptors has been identified in ACTH-independent macronodular adrenal hyperplasia (AIMAH) causing cortisol hypersecretion regulated by hormones other than ACTH. We aimed to determine aberrant expression of multiple hormone receptors in vivo and in vitro in adrenal tissue of a patient with AIMAH.

DESIGN

The design of the study includes clinical case description, and biochemical and immunohistochemical analysis to demonstrate aberrant expression of multiple hormone receptors in AIMAH.

METHODS

The subject of the study is a male diagnosed with Cushing's syndrome because of AIMAH. Directly after laparoscopic removal of the adrenals, adrenal tissue was incubated with and without test substances (ACTH, forskolin, arginine vasopressin (AVP), desmopressin, epinephrine, norepinephrine, purified human chorionic gonadotropin (hCG), metoclopramide and the combinations of AVP with ACTH, epinephrine and metoclopramide). LH/hCG-receptor (hCG-R) immunohistochemistry and RT-PCR analyses were performed to demonstrate aberrant expression of LH/hCG-R and V(1-3)-AVPR.

RESULTS

AIMAH was characterized by in vivo cortisol responsiveness to AVP and in vitro cortisol responses to AVP, hCG, epinephrine, and norepinephrine suggesting aberrant adrenal expression of the receptors for AVP (the V(1-3)-AVPRs), catecholamines (the beta-AR), and LH (the LH/hCG-R). Incubation with combinations of AVP and ACTH and of AVP with epinephrine induced a stronger cortisol response compared with incubation with the individual agents. Moreover, we demonstrated adrenal V(1-3)-AVPR and LH/hCG-R expression.

CONCLUSIONS

AIMAH tissue may simultaneously express multiple aberrant hormone receptors, and individual ligands may potentiate each other regarding cell proliferation and cortisol production.

Familial glucocorticoid deficiency with a point mutation in the ACTH receptor: a case report

Familial glucocorticoid deficiency (FGD) is a rare autosomal recessive disorder characterized by severe glucocorticoid deficiency associated with failure of adrenal responsiveness to ACTH but no mineralocorticoid deficiency. We report a 2 month-old boy of nonconsanguineous parents, presented with hyperpigmentation. Physical examination showed diffuse dark skin of body including, oral mucosa, gum, hands, nails and scrotum. Laboratory evaluation revealed low serum cortisol (0.3 microg/dL), with very high plasma ACTH level (18,000 pg/mL), and serum cortisol level did not increase after ACTH stimulation test. Serum sodium, potassium, plasma renin activity, aldosterone and 17-hydroxyprogesterone were normal. Sequence analysis of the ACTH receptor (MC2R) gene showed a homozygous mutation of D103N. Diagnosis of FGD was made and treatment started with oral hydrocortisone.

Homozygous nonsense and frameshift mutations of the ACTH receptor in children with familial glucocorticoid deficiency (FGD) are not associated with long-term mineralocorticoid deficiency

OBJECTIVE

Familial glucocorticoid deficiency (FGD) is a rare autosomal recessive disease characterized by isolated glucocorticoid deficiency with preserved mineralocorticoid secretion. Mutations in the ACTH receptor (MC2R) account for approximately 25% of all FGD cases, but since these are usually missense mutations, a degree of receptor function is frequently retained. A recent report, however, suggested that disturbances in the renin-aldosterone axis were seen in some patients with potentially more severe MC2R mutations. Furthermore, MC2R knock out mice have overt aldosterone deficiency and hyperkalaemia despite preservation of a normal zona glomerulosa. We wished to determine whether a group of patients with severe nonsense mutations of the MC2R exhibited evidence of mineralocorticoid deficiency, thereby challenging the conventional diagnostic feature of FGD which might result in diagnostic misclassification.

DESIGN

Clinical review of patients with nonsense MC2R mutations.

PATIENTS

Between 1993 and 2008, 164 patients with FGD were screened for mutations in the MC2R. Totally 42 patients (34 families) were found to have mutations in the MC2R. Of these, 6 patients (4 families) were found to have homozygous nonsense or frameshift mutations.

RESULTS

Mild disturbances in the renin-angiotensin-aldosterone axis were noted in four out of six patients, ranging from slightly elevated plasma renin levels to low aldosterone levels, although frank mineralocorticoid deficiency or electrolyte disturbance were not found. No patient required fludrocortisone replacement.

CONCLUSION

Severe nonsense and frameshift MC2R mutations are not associated with clinically significant mineralocorticoid deficiency and are thus unlikely to require long-term mineralocorticoid replacement.

[Rare disorders of glucocorticoid production, metabolism and action]

Glucocorticoids belong to the most important human hormones which are involved in the regulation of a variety of cardiovascular, metabolic and immunologic functions. Because they are necessary to sustain life and maintain homeostasis - adrenal disorders, if not detected in a timely fashion, can have serious consequences. The significant progress in the fields of hormonal assessment, imaging procedures and molecular biology made in recent years has brought about great improvement in the identification, differentiation and treatment of various adrenal disorders and has enabled the description of some new clinical entities. Abnormally high or abnormally low tissue glucocorticoid levels may either coexist with or result in deficiency or excess of mineralocorticoids and/or adrenal androgens. This review summarises the present state of knowledge on the pathogenesis, clinical picture, diagnosis and management of the selected rare disorders of glucocorticoid production, metabolism and their receptor action.

Phosphodiesterase 11A expression in the adrenal cortex, primary pigmented nodular adrenocortical disease, and other corticotropin-independent lesions

A variety of adrenal tumors and bilateral adrenocortical hyperplasias (BAH) leading to Cushing syndrome (CS) may be caused by aberrant cAMP signaling. We recently identified patients with a micronodular form of BAH that we have called "isolated micronodular adrenocortical disease" (iMAD) in whom CS was associated with inactivating mutations in phosphodiesterase (PDE) 11A ( PDE11A). In the present study, we examined PDE11A expression in normal adrenocortical tissue, sporadic tumors, and hyperplasias without PDE11A mutations, and primary pigmented nodular adrenocortical disease (PPNAD) and adenomas from patients with PRKAR1A and a single tumor with a GNAS mutation. The total number of the tumor samples that we studied was 22. Normal human tissues showed consistent PDE11A expression. There was variable expression of PDE11A in sporadic adrenocortical hyperplasia or adenomas; PPNAD tissues from patients with PRKAR1A mutations expressed consistently high levels of PDE11A in contrast to adenomas caused by GNAS mutations. Phosphorylated CREB was the highest in tissues from patients with iMAD compared to all other forms of BAH and normal adrenal tissue. We conclude that PDE11A is expressed widely in adrenal cortex. Its expression appears to be increased in PPNAD but varies widely among other adrenocortical tumors. PRKAR1A expression appears to be higher in tissues with PDE11A defects. Finally, sequencing defects in PDE11A are associated with a high state of CREB phosphorylation, just like PRKAR1A mutations. These preliminary data suggest that these two molecules are perhaps regulated in a reverse manner in their control of cAMP signaling in adrenocortical tissues.

Adrenal steroid metabolism in birds: anatomy, physiology, and clinical considerations

The hypothalamo-pituitary-adrenal system in birds is anatomically and functionally different from that in mammals. The adrenal gland structure and corticosteroid hormone physiology of birds will be reviewed. The anatomy and physiology sections of this article will be important for better understanding the pathogenesis, diagnosis, and possible treatment of primary or secondary adrenal gland disease. Causes of hyper- and hypoadrenocorticism in birds also will be reviewed. The article will conclude with current indications and complications to the clinical use of glucocorticoids in birds.

[Current views on the role of dehydroepiandrosterone in physiology, pathology and therapy]

Dehydroepiandrosterone (DHEA) and its sulfate metabolite (DHEAS) are the major androgens secreted by the human adrenal gland. The decline in their production is the most characteristic age-related change in the adrenal cortex. This process, known as 'adrenopause' may contribute to the increased incidence of atherosclerosis, cancer, or dementia in older people. The possibility of using DHEA in management has attracted considerable attention over recent years. Whereas DHEA therapy seems to be effective in treating patients with adrenal insufficiency and systemic lupus erythematosus, clinical studies investigating the potential efficacy of DHEA therapy in multiple other disorders (Alzheimer disease, depression, cardiovascular disease, osteoporosis, sexual dysfunctions) have not provided consistent results. Further research is also needed to better assess the efficacy and safety of DHEA supplementation in patients with advanced age. This review evaluates current understanding of physiology and pathology of DHEA production and summarizes the possible therapeutic value of this hormone.

Effects of cortisol on carbohydrate, lipid, and protein metabolism: studies of acute cortisol withdrawal in adrenocortical failure

CONTEXT

Cortisol is an important catabolic hormone, but little is known about the metabolic effects of acute cortisol deficiency.

OBJECTIVE

The objective of the study was to test whether clinical symptoms of weight loss, fatigue, and hypoglycemia could be explained by altered energy expenditure, protein metabolism, and insulin sensitivity during cortisol withdrawal in adrenocortical failure.

DESIGN, PARTICIPANTS, AND INTERVENTION

We studied seven women after 24-h cortisol withdrawal and during replacement control during a 3-h basal period and a 3-h glucose clamp.

RESULTS

Cortisol withdrawal generated cortisol levels close to zero, a 10% decrease in basal energy expenditure, increased TSH and T(3) levels, and increased glucose oxidation. Whole-body glucose and phenylalanine turnover were unaltered, but forearm phenylalanine turnover was increased. During the clamp glucose, infusion rates rose by 70%, glucose oxidation rates increased, and endogenous glucose production decreased. Urinary urea excretion decreased by 40% over the 6-h study period.

CONCLUSIONS

Cortisol withdrawal increased insulin sensitivity in terms of increased glucose oxidation and decreased endogenous glucose production; this may induce hypoglycemia in adrenocortical failure. Energy expenditure and urea loss decreased, indicating that weight and muscle loss in Addison's disease is caused by other mechanisms, such as decreased appetite. Increased muscle protein breakdown may amplify the loss of muscle protein.

The corticotropin-releasing factor (CRF) family of peptides as local modulators of adrenal function

Corticotropin-releasing factor (CRF), also termed corticotropin-releasing hormone (CRH) or corticoliberin, is the major regulator of the adaptive response to internal or external stresses. An essential component of the adaptation mechanism is the adrenal gland. CRF regulates adrenal function indirectly through the central nervous system (CNS) via the hypothalamic-pituitary-adrenal (HPA) axis and via the autonomic nervous system by way of locus coeruleus (LC) in the brain stem. Accumulating evidence suggests that CRF and its related peptides also affect the adrenals directly, i.e. not through the CNS but from within the adrenal gland where they form paracrine regulatory loops. Indeed, CRF and its related peptides, the urocortins (UCNs: UCN1, UCN2 and UCN3), their receptors CRF type 1 (CRF(1)) and 2 (CRF(2)) as well as the endogenous pseudo-receptor CRF-binding protein (CRF-BP) are all expressed in adrenal cortical, medullary chromaffin and resident immune cells. The intra-adrenal CRF-based regulatory system is complex and depends on the balance between the local concentration of CRF ligands and the availability of their receptors.

18F-Fluorodeoxy glucose (FDG) uptake in nontraumatic bilateral adrenal hemorrhage secondary to heparin-associated thrombocytopenia syndrome (HATS)—a case report

(18)F-Fluorodeoxy glucose (FDG) activity reflects tissue glucose metabolism; malignancies, metastases, and acute infections have relatively increased FDG activity reflecting increased glucose metabolism. Benign adrenal disease demonstrating mild FDG uptake can be worrisome for metastasis in patients with a history of malignancy. Our patient with breast and colon cancer developed gastrointestinal bleeding on heparin therapy, enlarged adrenals with heterogeneous attenuation consistent with hemorrhage and blood clots as seen on abdominal computed tomography scan, and as abnormal intense FDG activity in the bilateral adrenal glands on positron emission tomography scan.

DAX1: Increasing complexity in the roles of this novel nuclear receptor

DAX1 (NR0B1) is a nuclear receptor with a characteristic C-terminal ligand binding domain, but an atypical DNA binding domain. Mutations in the DAX1 gene cause adrenal hypoplasia congenita (AHC) establishing its biological importance. Recent studies highlight the complexities of DAX1 regulation and function. There is considerable phenotypic variability in AHC suggesting the existence of DAX1 modifier genes and environmental influences on DAX1 function. The findings of an alternatively spliced DAX1A, more common than DAX1 in all tissues except testis, of DAX1 homodimers, and of DAX1 heterodimers with a number of transcription factor partners including DAX1A and SHP point to an expanded transcription regulatory network under DAX1 control. Model organisms (mice and zebrafish) are being used to identify other DAX1 functions and modifier genes to understand the pathogenesis of AHC and the lack of genotype-phenotype correlation.

Assessing adrenal function in primary care settings with a single sample subcutaneous glucagon test

OBJECTIVE

To test the efficacy of the low-dose glucagon test in assessing adrenal gland function.

STUDY DESIGN

Subcutaneous glucagon was used to assess the hypothalamo-pituitary-adrenal gland (HPA) axis in 215 healthy children. Concordance of this test with the low-dose intravenous ACTH test was established for 42 children. Glucagon testing was conducted for 150 minutes after subcutaneous glucagon administration and for 30 minutes after 1 microg intravenous ACTH.

RESULTS

Mean peak serum cortisol concentrations were 22.4 +/- 0.6 microg/dL (SEM) after subcutaneous glucagon and 20.0 +/- 0.6 microg/dL after intravenous ACTH. Specificity of 95% was found at peak cortisol concentrations of 9.5 and 12.5 microg/dL for the glucagon and ACTH tests, respectively. Concordance between the glucagon and ACTH tests was 90.5%.

CONCLUSIONS

The glucagon test was found to be as good a test of the HPA axis as the ACTH test and had a 90.5% concordance with it. The ease of performing the glucagon test, namely, obtaining a single sample of blood 150 minutes after the subcutaneous administration of glucagon, makes it a useful method of assessing the HPA axis in primary care settings.

Sustentaculoma

A case of a morphologically distinctive tumor of the adrenal medulla occurring in a 54-year-old woman is described. On microscopic examination, the tumor was well circumscribed and characterized by the presence of ill-defined, irregular nests of spindle cells with oval to elongated nuclei, tiny nucleoli, and abundant eosinophilic cytoplasm. The tumor was associated with a moderate infiltrate of lymphocytes and plasma cells with occasional lymphoid follicles. Necrosis, marked cellular atypia, and mitoses were absent. Immunohistochemical studies demonstrated the tumor cells to be strongly reactive for vimentin, S-100 protein, and CD56, and nonreactive for glial fibrillary acidic protein, chromogranin, synaptophysin, melanoma-associated antigens, and dendritic cell markers. Ultrastructural examination showed elongated cells with interdigitating cytoplasmic processes devoid of a basal lamina. No secretory granules were noted. The morphology, immunophenotype, and ultrastructure of this unique neoplasm suggest derivation from sustentacular cells of the adrenal medulla. We propose the designation "sustentaculoma" for this hitherto undescribed neoplasm of the adrenal gland.

High 18F-fluorodeoxyglocose uptake in adrenal histoplasmosis; a case report

Adrenal histoplasmosis is one of the most common adrenal granulomatous infections in endemic areas. Although CT or MRI findings of adrenal histoplasmosis have been documented, there are no reports regarding 18F-fluorodeoxyglocose (FDG) positron emission tomography (PET) findings. We report a case of bilateral adrenal histoplasmosis showing a significantly high uptake of 18F-fluorodeoxyglocose on PET study. Adrenal histoplasmosis should be considered as one of the differential diagnoses in cases of adrenal tumors with intense FDG uptake, even in non-endemic areas.

Fetal and maternal adrenals in human pregnancy

Human pregnancy is marked by alterations in several endocrine systems--perhaps most notably, the striking increase in steroid hormone production by the adrenals of the fetus and mother. Morphologically and physiologically, the human fetal adrenal glands are remarkable organs. In proportion to the adult organs, the adrenal cortex is the largest organ of the fetus. At term, they produce more steroid and weigh the same as adrenal glands of the adult. Much of the steroid that is released by the fetal and maternal adrenals during pregnancy is the sulfated form of dehydroepiandrosterone (DHEA-S), which is used by the placenta to produce estrogens. Herein, we discuss the physiologic and pathophysiologic hormonal changes of the fetal and maternal adrenals during the course of pregnancy.

The triple A syndrome is due to mutations in ALADIN, a novel member of the nuclear pore complex

The triple A syndrome (MIM#231550) is a rare autosomal recessive disorder characterized by adrenocorticotropic hormone (ACTH) resistant adrenal failure, achalasia, alacrima, and a variety of neurological and dermatological features. The triple A syndrome is caused by mutations in the AAAS gene, which encodes a protein known as ALADIN (ALacrima Achalasia aDrenal Insufficiency Neurologic disorder). ALADIN is a new WD-repeat protein that has no significant homology to any previously identified WD-repeat protein. It has been shown that it colocalizes with nuclear pore complexes (NPCs), a finding that strongly suggests an involvement of ALADIN in nucleocytoplasmic transport. An investigation of 110 families with triple A syndrome disclosed mutation hot spots including Q15K (exon 1), and S293P (exon 8), which occur in 17 and 21 families from different geographical regions, respectively. The variable phenotype of all patients cannot be correlated with the localization and the nature of the ALADIN mutations. Thus, modifying genes/factors may be involved in the progression of this neurodegenerative disease. The lack of AAAS mutations in eight patients and negative linkage to chromosome 12q13 in three families are suggestive of genetic heterogeneity. To examine the cellular localization of ALADIN mutants causing triple A syndrome, we investigated nine different ALADIN-mutants: 2 nonsense (W84X, Q456X), 2 frameshift (F157fsX171, G397fsX414) and 5 point mutations (Q15K, L25P, H160R, S263P, L381R) by transfection experiments with green fluorescence protein. Mutants were predominantly localized in the cytoplasm, but also found in the nucleus indicating that ALADIN is essential for NPC targeting. To investigate physiological functions of ALADIN in vivo, we generated and analysed Aaas-/- knockout mice by homologous recombination in embryonic stem cells. Surprisingly, required animals lack any gross abnormality in adrenal and nervous system function. Further studies have to investigate the role of ALADIN at NPCs and to identify interacting proteins. Functional analyses of ALADIN may permit further understanding of its role for adrenocortical function and neurodevelopment.

Hypoglycemia and the sympathoadrenal system: neurogenic symptoms are largely the result of sympathetic neural, rather than adrenomedullary, activation

The relative contributions of the sympathetic nervous system and the adrenal medullae, the two components of the sympathoadrenal system, to the manifestations of hypoglycemia are largely unknown. We tested the hypothesis that the neurogenic symptoms of hypoglycemia are largely the result of sympathetic neural activation. To do so, we quantitated neurogenic symptoms, as well as norepinephrine (NE) kinetics and selected hemodynamic changes, during hyperinsulinemic euglycemic and stepped hypoglycemic clamps in 15 healthy control subjects (Controls) and four bilaterally adrenalectomized patients (ADX). Plasma epinephrine responses to hypoglycemia were virtually absent in ADX, as expected. Neurogenic symptom scores increased to higher values during the hypoglycemic compared with the euglycemic clamps in both Controls (P < 0.0001) (e.g., final scores of 7.8 +/- 1.2 vs. 3.0 +/- 0.7) and ADX (P < 0.0001) (e.g., final scores of 10.8 +/- 4.1 vs. 2.5 +/- 1.0). Plasma NE concentrations (P < 0.0001) and systemic NE spillover (P = 0.0007) increased during the hypoglycemic compared with the euglycemic clamps in Controls but not in ADX. Similarly, heart rate increased (P = 0.0104), diastolic blood pressure decreased (P = 0.0003), and forearm blood flow increased (P < 0.0001) during the hypoglycemic compared with the euglycemic clamps in Controls but not in ADX. These data indicate that the neurogenic symptoms of hypoglycemia are largely the result of sympathetic neural, rather than adrenomedullary, activation. They also suggest that the plasma NE and hemodynamic responses to hypoglycemia are largely the result of adrenomedullary, rather that sympathetic neural, activation.

[Genetic adrenal diseases]

The development of molecular biological techniques has unveiled much information on the pathogenesis of many disease at the DNA and RNA level, as well as provided a considerable improvement in diagnostic potential and treatment. The advantages achieved in molecular biology and genetic engineering have also found application in endocrinology. This paper reviews current knowledge on the role of genetic factors in the pathogenesis of adrenal diseases. Congenital adrenal hyperplasia, idiopathic hyperaldosteronism, adrenal hypoplasia congenita, autoimmune polyendocrinopathy candidiasis ectodermal dystrophy, ACTH resistance syndrome, and adrenal hereditary tumors are described.

The risk of functional ovarian hyperandrogenism and polycystic ovary syndrome in patients with hyperandrogenism

To describe the presence of dysregulations in steroid biosynthesis and the risk of functional ovarian hyperandrogenism (FOH) and polycystic ovary syndrome (PCOS)-like development in children with hyperandrogenism, 28 girls were studied. Adrenal steroidogenic profile was defined by basal and ACTH-stimulated levels of 17OHP, cortisol, DHEAS and androstenedione, and delta precursor/delta product ratios. Ovarian hyperandrogenism was defined by 17OHP response to LHRH stimulation, and pelvic ultrasonography (US) was performed to evaluate ovarian morphology. Basal and ACTH-stimulated hormonal results revealed non-classical 21-hydroxylase deficiency-like status in one patient (3.6%), and 21-hydroxylase deficiency heterozygote carrier-like state in four patients (14.3%), while the other 23 patients (82.1%) had functional adrenal hyperandrogenism (FAH). Among these patients with FAH, 47.83% had FOH; when these patients were evaluated by pelvic US, 30.4% had morphological changes which were not concordant with their age. We suggest that even mild forms of hyperandrogenism must be considered seriously and dysregulations of the steroidogenic pathway and ovarian abnormalities must be evaluated carefully to determine the risk of FOH/PCOS.

Replacement of dehydroepiandrosterone in adrenal failure: no benefit for subjective health status and sexuality in a 9-month, randomized, parallel group clinical trial

The physiological role of dehydroepiandrosterone (DHEA) is not well understood, but studies suggest positive effects on subjective health and bone metabolism. We have conducted a clinical trial with DHEA replacement in adrenal failure with the primary aim of evaluating effects on subjective health status and sexuality. Thirty-nine women with adrenal failure were randomized to 9 months of treatment with 25 mg DHEA (n = 19) or placebo (n = 20). Treatment effects were assessed by validated questionnaires of subjective health and sexuality. DHEA replacement yielded a wide variation of effects on the subjective health scales, which were not different from the effects of placebo. Almost all patients receiving DHEA obtained normal androgen levels. Eighty-nine percent of the patients receiving DHEA experienced side-effects, in particular increased sweat odor and scalp itching. DHEA replacement did not significantly change the levels of blood lipids, IGF-I, and markers of bone metabolism. In conclusion, we do not find evidence of beneficial effects of DHEA on subjective health status and sexuality in adrenal failure. However, DHEA may be beneficial for subgroups of patients with adrenal failure, but these remain to be identified. Premenopausal androgen levels can be restored with 25 mg DHEA daily in most female patients, but side-effects are frequent.

Adrenal pseudocyst mimicking a pheochromocytoma found after a traffic accident

We report a case of adrenal pseudocyst difficult to differentiate from pheochromocytoma. A right adrenal mass was found in a 41-year-old man after a traffic accident. Plasma level of renin was low, plasma level of aldosterone, and urine levels of aldosterone and catecholamines were high. Dynamic tests for primary aldosteronism and pheochromocytoma were negative. No abnormal uptake was shown in 131I-adosterol or 131I-MIBG scintigram. Adrenal venous sampling presented high levels of catecholamines. Laparoscopic adrenalectomy was performed. Histological examination revealed a pseudocyst with a thick fibrocollagenous wall. We discuss the mechanism of high catecholamine levels in the right adrenal vein.

[Immunohistochemical identification of adrenomedullin in adrenal diseases]

OBJECTIVE

Adrenomedullin (ADM) is a hypotensive peptide isolated from human pheochromocytoma tissue. In order to identify the pathophysiological effects of ADM on the etiology of adrenal diseases which can induce hypertension, the localization of immunoreactive adrenomedullin (ir-ADM) in adrenal tissue of subjects with normal adrenal and patients with different adrenal diseases was investigated by means of immunohistochemical staining.

METHODS

Peroxidase anti-peroxidase complex method was undertaken in the tissue of human adrenal cortex (n = 10) and medulla (n = 10)of subjects with normal adrenal, as well as in the tissue of pheochromocytoma (n = 31), primary aldosteronism including adrenocortical adenoma (n = 13) and hyperplasia (n = 9), Cushing's syndrome including adrenocortical adenoma (n = 12), hyperplasia (n = 10), carcinoma (n = 4) and non-functional adrenocortical carcinoma (n = 7).

RESULTS

Positive immunohistochemical staining of ir-ADM was observed in all the cases of normal adrenal medulla and 16 of the 31 cases of pheochromocytoma. The intensity of immunohistochemical staining of ir-ADM in the majority of pheochromocytoma was lower than that in normal adrenal medulla (P < 0.01). The number of pheochromocytoma cases with positive staining in paroxysmal hypertensive group was higher than that in sustained hypertensive group (P < 0.05). Negative immunohistochemical staining was found in all the cases of normal human adrenal cortex, adrenocortical adenoma, hyperplasia and carcinoma.

CONCLUSION

It is suggested that heterogeneous of localization of ir-ADM in pheochromocytoma tissue may be correlated to the diversity of blood pressure in patients with pheochromocytoma. The pathophysiological effects of ADM on the etiology of pheochromocytoma should be further investigated.

Overexpression of serotonin4 receptors in cisapride-responsive adrenocorticotropin-independent bilateral macronodular adrenal hyperplasia causing Cushing's syndrome

The serotonin4 (5-HT4) receptor agonists cisapride and/or metoclopramide have been shown to stimulate cortisol secretion in some patients with ACTH-independent bilateral macronodular adrenal hyperplasias (AIMAH) causing Cushing's syndrome. In the present study, we have investigated quantitatively and qualitatively the expression of the 5-HT4 receptor in both normal adrenal cortex and tissues removed from six patients (P1-P6) with cisapride-responsive AIMAH and Cushing's syndrome. Real-time quantitative PCR assay revealed that the 5-HT4 receptor was overexpressed in four of the six hyperplasias studied when compared with normal adrenal cortex. In these tissues, 5-HT4 receptor mRNA expression was 3 to 16 times higher than in normal glands, likely explaining the abnormal in vivo cortisol response to cisapride. Characterization of 5-HT4 receptor splice variants by RT-PCR in both hyperplastic and normal adrenals showed that the variants present in the two hyperplasias that did not overexpress the 5-HT4 receptor, i.e. P2 and P5, could also be detected in the normal adrenal tissue. In addition, sequencing of the full-length cDNAs encoding 5-HT4 receptors in hyperplasias P2 and P5 did not reveal any mutation. Taken together, our results show an overexpression of the 5-HT4 receptor in cisapride-responsive AIMAH. However, in two cases, the level of expression of the receptor in the hyperplastic adrenal cortex was similar to that of normal adrenal gland. The enhanced sensitivity of these two tissues to 5-HT4 receptor agonists was not due to ectopic expression of 5-HT4 receptor isoforms or to the occurrence of somatic gain-of-function mutation of the receptor.