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Glucocorticoid production in mammals is principally regulated by the action of the pituitary hormone adrenocorticotropin (ACTH) acting on its cognate membrane receptor on the zona fasciculata cells of the adrenal cortex. The receptor for ACTH consists of two essential components, a small seven transmembrane domain G protein-coupled receptor of the melanocortin receptor subgroup known as the melanocortin 2 receptor (MC2R) and a small single transmembrane domain protein that adopts a antiparallel homodimeric form and which is known as the melanocortin 2 receptor accessory protein (MRAP). MRAP is essential for the trafficking of the MC2R to the cell surface as well as being required for receptor responsiveness to ACTH at physiological concentrations—probably by facilitating ACTH binding, but possibly also by supporting G protein interaction with the MC2R. A number of studies have shown that ACTH stimulates the expression of functional receptor at the cell surface and the transcription of both MC2R and MRAP mRNA. However, the time course of these transcriptional effects differs such that MRAP is expressed relatively rapidly whereas MC2R transcription responds much more slowly. Furthermore, recent data suggests that MRAP protein is turned over with a short half-life whereas MC2R has a significantly longer half-life. These findings imply that these two ACTH receptor proteins have distinct trajectories and that it is likely that MRAP-independent MC2R is present at the cell surface. In such a situation newly transcribed and translated MRAP could enable the rapid recruitment of functional receptor at the plasma membrane without the need for new MC2R translation. This may be advantageous in circumstances of significant stress in that the potentially complex and perhaps inefficient process of de novo MC2R translation, folding, post-translational modification and trafficking can be avoided. [ABSTRACT FROM AUTHOR]

OBJECTIVE Activating mutations of the ACTH receptor have not been previously described. We investigated a 69-year-old woman with normal blood cortisol but undetectable blood ACTH concentrations. The aim of this study was to evaluate her hypothalamo–pituitary–adrenal axis by measuring circadian variation in blood ACTH and cortisol, and by performing CRH and ACTH stimulation and dexamethasone suppression tests. We also examined biological activity of her circulating blood ACTH using bovine adrenocortical cell suspensions and ACTH receptor gene structure by Northern blotting analysis. RESULTS Random plasma cortisol concentrations ranged from 182 to 328 nmol/l, while ACTH concentrations were always undetectable. After an intravenous bolus injection of human CRH 100 μg, plasma ACTH rose slightly, while plasma cortisol increased appropriately. ACTH stimulation tests revealed that a small amount of ACTH (5 ng/kg b.w.) had the maximal cortisol stimulatory activity, and even smaller amounts of ACTH (0.5 and 0.05 ng/kg b.w.) produced significant increases in cortisol levels. ACTH bioassay of the patient's plasma demonstrated weak biological activity in the HPLC fractions which corresponded to the band of synthetic human ACTH 1–39. The ACTH receptor coding region was amplified by polymerase chain reaction using the leucocyte genomic DNA. There were two base mutations; cysteine 21 → arginine and serine 247 → glycine in the sequences coding for the first extramembranous N-terminal domain and the third extramembranous loop of the ACTH receptor. CONCLUSIONS This patient with normal blood cortisol but undetectable ACTH levels showed increased adrenocortical sensitivity to ACTH and two point mutations in the ACTH receptor gene. This study, therefore, reports a previously undescribed syndrome—ACTH hypersensitivity syndrome—and provides insights into the molecular mechanism of ACTH receptor action. [ABSTRACT FROM AUTHOR]

We report a 30-year-old female with adrenal unresponsiveness to ACTH. Her clinical features included no adrenal crisis despite poor drug compliance, poor pubic hair development (Tanner stage 2), well-developed breasts (Tanner stage 5), and regular menstrual cycles. Endocrinological data included blood ACTH 1500 pmol/l, cortisol 18 nmol/l, dehydroepiandrosterone sulphate below 0.26 μmol/l, activated renin 0.37 pmol/l, and aldosterone 3.4 nmol/l. Direct sequencing and allele-specific amplification revealed two novel mutations in the ACTH receptor gene. One was transition from guanine to adenine at nucleotide position 1002, resulting in substitution of aspartate for asparagine at codon 103, and the other was transition from cytosine to thymine at nucleotide 1104, leading to substitution of arginine for tryptophan at codon 137. The present findings lend additional credence to the notions that adrenal androgens play an important role in female pubic hair development and that ovarian development takes place independently of adrenarche. [ABSTRACT FROM AUTHOR]

Coincidentally, the release of this Research Topic in Frontiers in Endocrinology takes place 25 years after the discovery of the adrenocorticotropic hormone receptor (ACTHR) by Mountjoy and colleagues. In subsequent years, following the discovery of other types of mammalian melanocortin receptors (MCRs), ACTHR also became known as melanocortin type 2 receptor (MC2R). At present, five types of MCRs have been reported, all of which share significant sequence similarity at the amino acid level, and all of which specifically bind melanocortins (MCs)--a group of biologically active peptides generated by proteolysis of the proopiomelanocortin precursor. All MCs share an identical -H-F-R-W- pharmacophore sequence. α-Melanocyte-stimulating hormone (α-MSH) and adrenocorticotropic hormone (ACTH) are the most extensively studied MCs and are derived from the same region. Essentially, α-MSH is formed from the first 13 amino acid residues of ACTH. ACTHR is unique among MCRs because it binds one sole ligand--ACTH, which makes it a very attractive research object for molecular pharmacologists. However, much research has failed, and functional studies of this receptor are lagging behind other MCRs. The reason for these difficulties has already been outlined by Mountjoy and colleagues in their publication on ACTHR coding sequence discovery where the Cloudman S91 melanoma cell line was used for receptor expression because it was a "more sensitive assay system." Subsequent work showed that ACTHR could be successfully expressed only in endogenous MCR-expressing cell lines, since in other cell lines it is retained within the endoplasmic reticulum. The resolution of this methodological problem came in 2005 with the discovery of melanocortin receptor accessory protein, which is required for the formation of functionally active ACTHR. The decade that followed this discovery was filled with exciting research that provided insight into the molecular mechanisms underlying the action of ACTHR. The purpose of this review is to summarize the advances in this fascinating research field. [ABSTRACT FROM AUTHOR]

Abstract  Tritium-labeled synthetic fragments of human adrenocorticotropic hormone (ACTH) [3H]ACTH (11–24) and [3H]ACTH (15–18) with a specific activity of 22 and 26 Ci/mmol, respectively, were obtained. It was found that [3H]ACTH-(11–24) binds to membranes of the rat adrenal cortex with high affinity and high specificity (K d 1.8 ± 0.1 nM). Twenty nine fragments of ACTH (11–24) were synthesized, and their ability to inhibit the specific binding of [3H]ACTH (11–24) to adrenocortical membranes was investigated. The shortest active peptide was found to be an ACTH fragment (15–18) (KKRR) (K i 2.3 ± 0.2 nM), whose [3H] labeled derivative binds to rat adrenocortical membranes (K d 2.1 ± 0.1 nM) with a high affinity. The specific binding of [3H]ACTH-(15–18) was inhibited by 100% by unlabeled ACTH (11–24) (K i 2.0 ± 0.1 nM). ACTH (15–18) in the concentration range of 1–1000 nM did not affect the adenylate cyclase activity of adrenocortical membranes and, therefore, is an antagonist of the ACTH receptor. [ABSTRACT FROM AUTHOR]

The ACTH receptor, also known as the melanocortin-2 receptor (MC2R), is critical for ACTH-mediated adrenal glucocorticoid release. Human MC2R (hMC2R) has 10 cysteine residues, which are located in extracellular loops (ELs), transmembrane domains (TMs), and intracellular loops (ILs). In this study, we examined the importance of these cysteine residues in receptor function and determined their involvement in disulfide bond formation. We replaced these cysteines with serine and expressed the mutated receptors in adrenal OS3 cells, which lack endogenous MC2R. Our results indicate that four mutations, C21S in NH2 terminus, C245S, C251S, and C253S in EL3, resulted in significant decrease both in receptor expression and receptor function. Mutation of cysteine 231 in TM6 significantly decreased ACTH binding affinity and potency. In contrast, the five other mutated receptors (C64S, C158S, C191S, C267S, and C293S) did not significantly alter ACTH binding affinity and potency. These results suggest that extracellular cysteine residue 21, 245, 251, and 253, as well as transmembrane cysteine residue 231 are crucial for ACTH binding and signaling. Further experiments suggest that a disulfide bond exists between the residue C245 and C251 in EL3. These findings provide important insights into the importance of cysteine residues of hMC2R for receptor function. [ABSTRACT FROM AUTHOR]

The late-gestation plasma cortisol surge in the sheep fetus is critical for stimulating organ development and parturition. Increased adrenal responsiveness is one of the key reasons for the surge; however, the underlying mechanisms are not fully understood. Our recent studies suggest that ACTH-mediated increased expression of ACTH receptor (ACTH-R) and steroid acute regulatory protein (StAR) may play a role in enhancing responsiveness. Hence, we examined effects of ACTH infusion in fetal sheep on mRNA expression of these two mediators of adrenal responsiveness and assessed the functional consequences of this treatment in vitro. Fetuses of ~118 and 138 days of gestational age (dGA) were infused with ACTH-(1-24) for 24 h. Controls received saline infusion. Arterial blood was sampled throughout the infusion. Adrenals were isolated and analyzed for ACTH-R and StAR mRNA, or cells were cultured for 48 h. Cells were stimulated with ACTH, and medium was collected for cortisol measurement. Fetal plasma ACTH and cortisol concentrations increased over the infusion period in both groups. ACTH-R mRNA levels were significantly higher in ACTH-infused fetuses in both the 118 and 138 dGA groups. StAR mRNA increased significantly in both the 118 and 138 dGA groups. Adrenal cells from ACTH-infused fetuses were significantly more responsive to ACTH stimulation in terms of cortisol secretion than those from saline-infused controls. These findings demonstrate that increases in circulating ACTH levels promote increased expression of ACTH-R and StAR mRNA and are coupled to heightened adrenal responsiveness. [ABSTRACT FROM AUTHOR]

Preparing the mammalian fetus for birth requires an increase in fetal plasma glucocorticoid levels. The mechanisms facilitating this increase are not fully known. It has been shown in sheep that the prepartum elevation in fetal plasma cortisol is accompanied by increases in adrenocorticotropin receptor (ACTH-R) expression in the fetal adrenal and in the adrenal responsiveness to stimulation. To determine the significance of the upregulation in ACTH-R expression on fetal adrenal function, the authors used small interfering RNA targeted to the ovine ACTH-R to reduce receptor expression and studied responses to stimulation in ovine adrenal cells. They studied fetal cells from late gestation after responsiveness had increased. They also studied adult cells to determine if maturation would influence the impact of receptor expression suppression on responsiveness. Fetal and adult cells were obtained, dispersed, transfected with receptor-targeted small interfering RNA or scrambled small interfering RNA, and subsequently stimulated with ACTH. Cells and media were harvested for measurements of gene and protein expression and cyclic adenosine monophosphate (cAMP) and cortisol levels. The ability of ACTH to upregulate its receptor or steroid acute regulatory protein was attenuated in fetal (P < .01) and adult cells (P < .01) by small interfering RNA treatment; the blockade was more pronounced in the adult cells (P < .01). The small interfering RNA treatment also blocked the cAMP response to ACTH in fetal (P < .001) and adult (P < .05) cells. This was accompanied by marked reductions in cortisol responses in both (P < .001 and P < .01, respectively). These data surest that upregulation of the ACTH-R expression in late gestation is essential for the increase in adrenal steroidogenic capacity occurring then. The data also indicate that a reduction in the ACTH-R expression blocks the ability of the peptide to stimulate early steps in the steroidogenic pathway event after maturation is complete. [ABSTRACT FROM AUTHOR]

Although it has been recognized for over a decade that hypothalamic-pituitary disconnection (HPD) in fetal sheep prevents the late gestation rise in plasma cortisol concentrations, the underlying mechanisms remain unclear. We hypothesized that reductions in adrenal responsiveness and ACTH receptor (ACTH-R) expression may be mediating factors. HPD or sham surgery was performed at 120 days of gestation, and catheters were placed for blood sampling. At ∼138 days of gestation, fetuses were killed, and adrenals were removed for cell culture and analyses of ACTH-R mRNA and protein. After 48 h, adrenocortical cells were stimulated with ACTH for 2 h, and the medium was collected for cortisol measurement. The same cells were incubated overnight with medium or medium containing ACTH or forskolin (FSK), followed by ACTH stimulation (as above) and cortisol and cellular ACTH-R mRNA analyses. HPD prevented the late gestation increase in plasma cortisol and bioactive ACTH and reduced adrenal ACTH-R mRNA and protein levels by over 35%. HPD cells secreted significantly less cortisol than sham cells (3.2 ± 1.2 vs. 47.3 ± 11.1 ng·ml-1·2 h-1) after the initial ACTH stimulation. Overnight incubation of HPD cells with ACTH or FSK restored cortisol responses to acute stimulation to levels seen in sham cells initially. ACTH-R mRNA levels in cells isolated from HPD fetuses were decreased by over 60%, whereas overnight incubation with ACTH or FSK increased levels by approximately twofold. Our findings indicate that the absence of the cortisol surge in HPD fetuses is a consequence, at least in part, of decreased ACTH-R expression and adrenal responsiveness. [ABSTRACT FROM AUTHOR]

Familial glucocorticoid deficiency (FGD), or hereditary unresponsiveness to adrenocorticotropin (ACTH; OMIM 202200), is an autosomal recessive disorder resulting from resistance to the action of ACTH on the adrenal cortex, which stimulates glucocorticoid production. Affected individuals are deficient in cortisol and, if untreated, are likely to succumb to hypoglycemia or overwhelming infection in infancy or childhood. Mutations of the ACTH receptor (melanocortin 2 receptor, MC2R) account for~25% of cases of FGD. FGD without mutations of MC2R is called FGD type 2. Using SNP array genotyping, we mapped a locus involved in FGD type 2 to chromosome 21q22.1. We identified mutations in a gene encoding a 19-kDa single-transmembrane domain protein, now known as melanocortin 2 receptor accessory protein (MRAP). We show that MRAP interacts with MC2R and may have a role in the trafficking of MC2R from the endoplasmic reticulum to the cell surface. [ABSTRACT FROM AUTHOR]

Please cite this paper as: Melanocortin receptor type 2 (MC2R, ACTH receptor) expression in patients with alopecia areata. Experimental Dermatology 2010; : 1020-1022. Human skin expresses elements of the hypothalamo-pituitary-adrenal (HPA) axis that function as a local stress response system. Because adrenocorticotropic hormone (ACTH) is an intermediate in the HPA axis from corticotropin-releasing hormone (CRH) signal to cortisol secretion, MC2R that binds only ACTH may be important in the stress response of skin. We investigated the local expression of MC2R by immunohistochemistry to identify the role of ACTH/MC2R in stress-associated alopecia areata (AA). MC2R appeared to be highly compartmentalized in scalp skin including the epidermal cells of hair follicles and epidermis, sebaceous and eccrine glands, as well as dermal fibroblasts. The expression of MC2R was lower in AA lesions than in normal scalp tissue in almost all scalp skin cells, especially in epithelial cells. These findings demonstrate that MC2R expression is aberrant in AA and suggest a deficit in ACTH/MC2R activity may play an important role in the pathophysiology of AA. [ABSTRACT FROM AUTHOR]

Tetrapeptide KKRR, corresponding to the ACTH15-18 sequence, is the shortest fragment with high-affinity binding with the ACTH receptor; it does not activate this receptor and prevents the whole hormone molecule from binding to it, and thus exhibits the properties of an ACTH receptor antagonist. The aim of the present work was to study the effects of peptide ACTH15-18 (KKRR) and its analog ACTH15-18PGP on behavior in Wistar rats in normal conditions and after acute stress produced by inescapable electrical foot shock. The peptides studied here did not affect the anxiety levels in white rats in normal conditions. Prior administration of ACTH15-18 (250 μg/kg) and its analog ACTH15-18PGP (50 and 250 μg/kg) decreased anxiety and corticosterone release in rats which had received a acute electrical foot shock stress. The extent and duration of the anti-stress effects of ACTH15-18PGP were significantly greater than the extent and duration of the effects of its natural prototype. [ABSTRACT FROM AUTHOR]

Testicular adrenal rest tumors (TARTs), commonly occurring in males with congenital adrenal hyperplasia, may arise from chronic stimulation of adrenocorticotropic hormone (ACTH)–sensitive cells in the testes. It is not yet established whether the human fetal testis (HFT) is responsive to ACTH. To investigate this, we cultured HFT tissue with and without ACTH for up to 5 days, and quantified adrenal steroid hormones and expression of adrenal steroidogenic enzymes. Fetal testis and adrenal tissue produced high levels of testosterone and cortisol, respectively, indicating viability. In contrast to fetal adrenal tissues, the expression of ACTH receptor MC2R was either absent or expressed at extremely low levels in ex vivo HFT tissue and no clear response to ACTH in gene expression or steroid hormone production was observed. Altogether, this study suggests that the HFT is unresponsive to ACTH, which would indicate that a TART does not arise from fetal testicular cells chronically exposed to ACTH in utero. [ABSTRACT FROM AUTHOR]

Alopecia areata (AA) is an autoimmune disease of the hair follicle. Keratinocytes of the hair follicle generate an immunosuppressive environment by the local secretion of hormones of the hypothalamic‐pituitary‐adrenal axis of the skin (skin HPA analog). Our objective was to measure the local production of corticotropin‐releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and α‐melanocyte‐stimulating hormone (α‐MSH) in the scalp tissue of patients with AA before and after ultraviolet A1 (UVA‐1) phototherapy to determine their role in the pathogenesis of AA and the effect of UVA‐1 on the AA hormonal environment. This was a retrospective and descriptive study of skin samples from 22 patients with AA before and after UVA‐1 treatment. We compared the changes in the local hormonal environment by measuring CRH, ACTH, type 2 melanocortin receptor (ACTH receptor) and α‐MSH with immunohistochemical stains. The positivity of MSH was significantly higher (P =.037) in the post‐treatment samples compared with the baseline value. ACTH was significantly higher in intensity (P =.032) in the post‐treatment samples compared with the initial value. CRH was significantly higher in intensity (P =.013) in baseline samples compared with the final biopsies. The positivity of the ACTH receptor MC2R was not different between the two groups (P =.626). In AA, an interruption in the signalling of CRH could decrease the local concentration of ACTH and MSH, and consequently, the immunosuppressive effect of these hormones. This phenomenon is normalized in the skin treated with UVA‐1. A defective signalling system in the cutaneous HPA axis may be involved in the pathogenesis of AA. [ABSTRACT FROM AUTHOR]

Adrenocorticotropic hormone (ACTH) induces lipolysis in a dose-dependent fashion in rodent adipose tissue and adipocytes in vitro. The role of ACTH on lipolysis in human adipose tissue is less clear, however. In this study, we address the hypothesis that ACTH induces lipolysis in human adipose tissue. We used ex vivo organ culture to examine lipolysis in human and mouse adipose tissue. Adipose tissue fragments suspended in culture medium and human ACTH, isoproterenol (positive control), or insulin (negative control) was added in varying concentrations. Lipolysis was measured using glycerol appearance. ACTH receptor mRNA expression was assessed using reverse-transcription polymerase chain reaction (RT-PCR). In mouse adipose tissue, ACTH induced lipolysis in dose-dependent manner; 100 pmol/l ACTH induced 67±19% of isoproterenol-stimulated lipolysis and 500 pmol/l ACTH: 86±13%. In contrast, human adipose tissue shared no significant response to 100 pmol/l ACTH; ACTH was associated with 9±6% and 500 pmol/l of ACTH, 8±6% of isoproterenol-stimulated lipolysis. ACTH receptor mRNA was present in mouse adipose tissue, but undetectable in human adipose tissue. These results suggest lipolysis regulation differs between human and mouse adipose tissue in response to ACTH. [ABSTRACT FROM AUTHOR]

Discusses the expression of ACTH receptor pathway genes in GIP-dependent Cushing's syndrome (CS). Regulation of the aberrant adrenal cortex regulation by GIP; Expression of several genes involved in the pathway in GIP-dependent CS; Correlation between the expression of ACTHR and the transcription factors.

Unlabelled: The syndrome of familial adrenocorticotropin (ACTH) unresponsiveness is a rare form of primary adrenal insufficiency, usually without mineralocorticoid deficiency. It is characterized by elevated plasma ACTH concentrations and undetectable plasma cortisol levels not responding to exogenous ACTH. Alacrima and achalasia have also been occasionally associated with adrenal insufficiency (triple A syndrome). Pathogenetic mutations have been identified in the ACTH receptor gene in families with isolated familial ACTH unresponsiveness. Whether the ACTH receptor represents the locus of the defect for the triple A syndrome is not known. Here we report two siblings with familial ACTH unresponsiveness who were discrepant for skin pigmentation and mineralocorticoid function. In addition, achalasia and alacrima were documented only in the older sibling. The boy, studied at the age of 2 years, was hyperpigmented, in contrast to his normally pigmented sister, studied at the age of 9 years; basal plasma alpha-melanocyte stimulating hormone immunureactivity levels were 79 and 38 pg/ml, respectively (normal < 40 pg/ml). Furosemide-induced diuresis resulted in normal rises of plasma renin activity in both patients; however, plasma aldosterone levels increased only in the boy and not in his sister. Screening for abnormalities of the ACTH receptor gene by single strand conformation polymorphism analysis revealed no abnormality. Direct sequencing of the entire coding area of the ACTH receptor gene was also normal.Conclusion: The syndrome of familial ACTH unresponsiveness can vary clinically and biologically within the same family.(ABSTRACT TRUNCATED AT 250 WORDS) [ABSTRACT FROM AUTHOR]

Familial glucocorticoid deficiency (FGD) is a rare autosomal recessive disease resulting from resistance to the action of adrenocorticotropic hormone (ACTH) on the adrenal cortex, which leads to isolated glucocorticoid deficiency with normal mineralocorticoid secretion. It may present in infancy or early childhood with hyperpigmentation, failure to thrive, recurrent infections, hypoglycemic attacks and convulsions that may result in coma or death. Laboratory investigations reveal low cortisol and androgen levels with high ACTH associated with normal reninaldosterone axis. The disorder may be caused by mutations in the gene of ACTH receptor (MC2R), or mutations in the newly described melanocortin- 2 receptor accessory protein (MRAP) namely, FGD type 1 and FGD type 2, respectively. Twenty five percent of FGD cases are due to the mutations of the ACTH receptor, while FGD type 2 accounts for approximately 15-20% of FGD cases. Here, we report a six-month-old male infant, who presented with recurrent hypoglycemic convulsions. Serum hormone analysis showed low cortisol and androgen levels associated with a high ACTH concentration. No mutation was found in the NR0B1 and MC2R genes excluding congenital adrenal hypoplasia and FGD type 1. We found a homozygous deletion (c. 106+1delG) in intron 3 of MRAP gene. To our knowledge, this is the first Turkish patient reported with FGD type 2 due to a known MRAP mutation. [ABSTRACT FROM AUTHOR]

Background: Primary pituitary carcinoma is rarely reported in dogs and only few reports describe its malignancy. In veterinary literature, primary pituitary carcinomas correspond up to 2.4% to 3.4% of intracranial neoplasms found in dogs and information regarding its biological behavior is quite limited. In humans, primary pituitary carcinomas represent less than 1.0% of all tumors found in the pituitary gland. The proposed classification for pituitary carcinoma in humans and dogs determines that the tumor must have its origin in adenohypophyseal region and disseminated metastasis by cerebrospinal fluid or systemically to other organs must be observed. In dogs, a few reports have described primary pituitary carcinoma. The goal of this report was to describe clinical, tomographic, histopathological and immunohistochemistry features of a bitch with primary pituitary carcinoma with adjacent invasion. Case: A 7-year-old female spayed Golden Retriever dog was assessed by general practice due progressive weight loss, muscular atrophy, lethargy, blindness, head pressing, and hyporexia for 21 days. Computed tomography (CT) showed a cerebral parenchyma with expansive extra-axial base formation, originating from sella turcica topography, measuring about 2.0 cm dorsally, displacing the third ventricle, suggesting the diagnosis of pituitary neoplasia. The hormones thyroidstimulating hormone (TSH) and total thyroxine (T4) as well as stimulation ACTH test were unremarkable. After 7 days, neurological clinical signs progressed and unfortunately the patient died ten days later after hospitalization. A necropsy exam revealed pituitary gland with increased dimensions (2.5 x 2.0 cm). Histopathological fi ndings revealed tumor proliferation in pituitary gland. The neoplasm showed invasion to the nervous parenchyma and metastatic foci between the brain lobes. Immunohistochemistry was positive for keratin and neuron-specifi c enolase and negative for epithelial membrane antigen, S-100 protein, glial fi brillary acidic protein, estrogen receptor, CD34, chromogranin, somatostatin, and ACTH. The clinical, histopathological and immunohistochemistry fi ndings supported the diagnosis of primary pituitary carcinoma. Discussion: There is lack information regarding pituitary carcinoma prevalence in dogs, and little is known about its pathological and clinical features. The patient showed a shorter survival time (30 days after the onset of clinical signs) for a non-hormonally functional tumor that presented with acute onset of neurological signs due to local effect of an expanding mass, also described in others pituitary carcinoma reports. It was observed a metastatic focus of pituitary neoplasia between cerebral hemispheres, leading us to conclude to be a pituitary carcinoma. Adjacent infiltration was noticed by the presence of neoplasm invasion to the synoptic nervous parenchyma and metastatic foci between the brain lobes as well as the presence of a non-delimited nodular area of neoplastic implantation between the cerebral hemispheres, and optic nerve compromised by neoplasm cells. The data reported here showed that a negative ACTH receptor in neoplasm with 10% Ki-67 proliferation index with no history of clinical signs of pituitary-dependent hyperadrenocorticism (PDH). Pituitary adenocarcinomas are thought to be more often non-secretors. CT findings reveled a pituitary mass of 2.5 cm in vertical height suggesting a pituitary macrotumor although there is lack of description for pituitary carcinomas in veterinary literature. The animal had a fast deterioration of his clinical condition and quickly came to death, suggesting poor biological behavior of the tumor. [ABSTRACT FROM AUTHOR]

Comments on the research by N. Hiroi et al. on human ACTH hypersensitivity associated with ACTH receptor gene abnormalities published in the journal 'Clinical Endocrinology.' Missense mutations in the ACTH receptor gene; ACTH receptor screening; Aspects of research that could result from the study.

The main hormone produced by the adrenal glands of hens is corticosterone, synthesized and secreted by stimulation of the HPA axis during stress. Direct activation of adrenal activity is conditioned by ACTH, which binds to the melanocortin receptor cMC2 in the adrenals and stimulates the synthesis and release of glucocorticosteroids. One of the factors that stimulate HPA axis activity is starvation, to which chickens are very sensitive. The purpose of this study was to determine the expression of ACTH receptor cMC2 in the adrenals of hens during shortterm fasting and after restoration of the proper level of nutrition (refeeding). The results of the experiment show that 24-hour food deprivation is stressful for the hen, as indicated by increased concentrations of corticosterone in the adrenals and blood plasma. Changes in cMC2R expression and the level of corticosterone in the adrenals during fasting and refeeding indicate a rapid increase in HPA axis activity in response to changing levels of nutrition. The results of the experiment confirm the direct effect of ACTH on corticosterone release by avian adrenal glands. [ABSTRACT FROM AUTHOR]

OBJECTIVE: ACTH resistance syndromes are rare, autosomal, and genetically heterogeneous diseases that include familial glucocorticoid deficiency (FGD) and triple A syndrome. FGD has been shown to segregate with mutations in the gene coding for ACTH receptor (MC2R) or melanocortin 2 receptor accessory protein (MRAP), whereas mutations in the triple A syndrome (AAAS, Allgrove syndrome) gene have been found in segregation with triple A syndrome. We describe the clinical findings and molecular analysis of MC2R, MRAP, and AAAS genes in five Brazilian patients with ACTH resistance syndrome. DESIGN AND METHODS: Genomic DNA from patients and their unaffected relatives was extracted from peripheral blood leucocytes and amplified by PCR, followed by automated sequencing. Functional analysis was carried out using Y6 cells expressing wild-type and mutant MC2R. RESULTS: All five patients showed low cortisol and elevated plasma ACTH levels. One patient had achalasia and alacrima, besides the symptoms of adrenal insufficiency. The molecular analysis of FGD patients revealed a novel p.Gly116Val mutation in the MC2R gene in one patient and p.Met1Ile mutation in the MRAP gene in another patient. Expression of p.Gly116Val MC2R mutant in Y6 cells revealed that this variant failed to stimulate cAMP production. The analysis of the AAAS gene in the patient with triple A syndrome showed a novel g.782_783delTG deletion. The molecular analysis of DNA from other two patients showed no mutation in MC2R, MRAP, or AAAS gene. CONCLUSIONS: In conclusion, the molecular basis of ACTH resistance syndrome is heterogeneous, segregating with genes coding for proteins involved with ACTH receptor signaling/expression or adrenal gland development and other unknown genes. [ABSTRACT FROM AUTHOR]

OBJECTIVEFamilial glucocorticoid deficiency (FGD) has frequently been associated with tall stature in affected individuals. The clinical, biochemical and genetic features of five such patients were studied with the aim of clarifying the underlying mechanisms of excessive growth in these patients. PATIENTS AND METHODSFive patients with a clinical diagnosis of FGD are described in whom the disorder resulted from a variety of novel or previously described missense or nonsense mutations of the ACTH receptor (MC2-R). All patients demonstrated excessive linear growth over that predicted from parental indices and increased head circumference. RESULTSGrowth hormone and IGF-I-values were normal. Growth charts suggest that the excessive growth is reduced to normal following the introduction of glucocorticoid replacement. A characteristic facial appearance including hypertelorism, marked epicanthic folds and prominent frontal bossing was noted. CONCLUSIONSThese findings indicate that ACTH resistance resulting from a defective ACTH receptor may be associated with abnormalities of cartilage and/or bone growth independently of the GH–IGF-I axis, but probably dependent on ACTH actions through other melanocortin receptors. [ABSTRACT FROM AUTHOR]

Adrenocorticotropin (ACTH) acts via a highly selective receptor that is a member of the melanocortin receptor subfamily of type 1 G protein-coupled receptors. The ACTH receptor, also known as the melanocortin 2 receptor (MC2R), is unusual in that it is absolutely dependent on a small accessory protein, melanocortin receptor accessory protein (MRAP) for cell surface expression and function. ACTH is the only known naturally occurring agonist for this receptor. This lack of redundancy and high degree of ligand specificity suggests that antagonism of this receptor could provide a useful therapeutic aid and a potential investigational tool. Clinical situations in which this could be useful include (1) Cushing's disease and ectopic ACTH syndrome - especially while preparing for definitive treatment of a causative tumor, or in refractory cases, or (2) congenital adrenal hyperplasia - as an adjunct to glucocorticoid replacement. A case for antagonism in other clinical situations in which there is ACTH excess can also be made. In this article, we will explore the scientific and clinical case for an ACTH antagonist, and will review the evidence for existing and recently described peptides and modified peptides in this role. [ABSTRACT FROM AUTHOR]

A 29-year-old woman was admitted in March 1998 due to high plasma ACTH levels, amenorrhea and uncontrolled diabetes mellitus (DM) which had persisted since 1991. Plasma ACTH levels showed a wide range of changes: they were usually high (59–240 pg/ml), intermittently very high (336–942 pg/ml), and sometimes normal or low. Plasma cortisol levels were usually normal but were sometimes high when the ACTH levels were very high. However, even when the plasma ACTH levels were very high, she did not show any cushingoid features. DM was diagnosed as non-insulin-dependent DM. Plasma ACTH showed an excessive response to CRH, while cortisol showed a delayed response. Plasma cortisol showed a poor response to ACTH-(1–24). ACTH receptor gene analysis revealed no mutations in the ACTH receptor-coding region. MRI showed a nonenhancing mass on the left side of the pituitary. Cavernous sinus sampling showed a very high plasma ACTH level in the left cavernous sinus compared with the levels in the right cavernous sinus and peripheral blood. Sephadex G-75 gel filtration of plasma ACTH immunoreactivity in plasma obtained by cavernous sinus sampling showed mainly high molecular forms of ACTH, probably proopiomelanocortin and ACTH-β-lipotropin. This case is a very rare form of pituitary adenoma showing intermittent secretion of high molecular ACTH unaccompanied by cushingoid features.Copyright © 2000 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The ectopic expression of the glucose-dependent insulinotropic polypeptide receptor (GIPR) in the human adrenal gland causes significant hypercortisolemia after ingestion of each meal and leads to Cushing’s syndrome, implying that human GIPR activation is capable of robustly activating adrenal glucocorticoid secretion. In this study, we transiently transfected the human GIPR expression vector into cultured human adrenocortical carcinoma cells (H295R) and treated them with GIP to examine the direct link between GIPR activation and steroidogenesis. Using quantitative RT-PCR assay, we examined gene expression of steroidogenic related proteins, and carried out immunofluorescence analysis to prove that forced GIPR overexpression directly promotes production of steroidogenic enzymes CYP17A1 and CYP21A2 at the single cell level. Immunofluorescence showed that the transfection efficiency of the GIPR gene in H295R cells was approximately 5%, and GIP stimulation enhanced CYP21A2 and CYP17A1 expression in GIPR-introduced H295R cells (H295R-GIPR). Interestingly, these steroidogenic enzymes were also expressed in the GIPR (–) cells adjacent to the GIPR (+) cells. The mRNA levels of a cholesterol transport protein required for all steroidogenesis, StAR, and steroidogenic enzymes, HSD3β2, CYP11A1, CYP21A2, and CYP17A1 increased 1.2-2.1-fold in GIP-stimulated H295R-GIPR cells. These changes were reflected in the culture medium in which 1.5-fold increase in the cortisol concentration was confirmed. Furthermore, the levels of adenocorticotropic hormone (ACTH) receptor and ACTH precursor proopiomelanocortin (POMC) mRNA were upregulated 2- and 1.5-fold, respectively. Immunofluorescence showed that ACTH expression was detected in GIP-stimulated H295R-GIPR cells. An ACTH-receptor antagonist significantly inhibited steroidogenic gene expression and cortisol production. Immunostaining for both CYP17A1 and CYP21A2 was attenuated in cells treated with ACTH receptor antagonists as well as with POMC siRNA. These results demonstrated that GIPR activation promoted production and release of ACTH, and that steroidogenesis is activated by endogenously secreted ACTH following GIP administration, at least in part, in H295R cells. [ABSTRACT FROM AUTHOR]

Melanocortin 4 receptor (MC4R), a canonical melanocyte-stimulating hormone receptor, is the main responsible for monogenic obesity in humans. Previous studies in fish and avian species showed that MC4R becomes an ACTH receptor after interaction with the melanocortin receptor accessory protein 2 (MRAP2). We show that human MC4R behaves in a similar way through its interaction with MRAP2. This evolutionary conservation of MRAP2-induced ligand selectivity supports a physiological role for the interaction with MC4R. Both proteins are coexpressed in the same hypothalamic neurons, providing an anatomical substrate and molecular mechanism for the central therapeutic actions of ACTH in the treatment of infantile spasms. These neurons may link the effects of stress on the energy balance independently of glucocorticoid secretion. The complex MC4R-MRAP2 throws light on the action of ACTH and, by extension, on the relay of stress-related information to additional biological systems. [ABSTRACT FROM AUTHOR]

The late gestation increase in adrenal responsiveness to adrenocorticotropin (ACTH) is dependent upon the upregulation of the ACTH receptor (ACTH-R), steroidogenic acute regulatory protein (StAR), and steroidogenic enzymes in the fetal adrenal. Long-term hypoxia decreases the expression of these and adrenal responsiveness to ACTH in vivo. Leptin, an adipocyte-derived hormone which attenuates the peripartum increase in fetal plasma cortisol is elevated in hypoxic fetuses. Therefore, we hypothesized that increases in plasma leptin will inhibit the expression of the ACTH-R, StAR, and steroidogenic enzymes and attenuate adrenal responsiveness in hypoxic fetuses. Spontaneously hypoxemic fetal sheep (132 days of gestation, PO2 ∼15 mm Hg) were infused with recombinant human leptin (n = 8) or saline (n = 7) for 96 hours. An ACTH challenge was performed at 72 hours of infusion to assess adrenal responsiveness. Plasma cortisol and ACTH were measured daily and adrenals were collected after 96 hours infusion for messenger RNA (mRNA) and protein expression measurement. Plasma cortisol concentrations were lower in leptin- compared with saline-infused fetuses (14.8 ± 3.2 vs 42.3 ± 9.6 ng/mL, P < .05), as was the cortisol:ACTH ratio (0.9 ± 0.074 vs 46 ± 1.49, P < .05). Increases in cortisol concentrations were blunted in the leptin-treated group after ACTH1-24 challenge (F = 12.2, P < .0001). Adrenal ACTH-R, StAR, and P450c21 expression levels were reduced in leptin-treated fetuses (P < .05), whereas the expression of Ob-Ra and Ob-Rb leptin receptor isoforms remained unchanged. Our results indicate that leptin blunts adrenal responsiveness in the late gestation hypoxemic fetus, and this effect appears mediated by decreased adrenal ACTH-R, StAR, and P450c21 expression. [ABSTRACT FROM AUTHOR]

Abstract  The activity of the KKRR synthetic peptide corresponding to the 15-18 sequence of human adrenocorticotropic hormone (ACTH) and its analogues: KKKK, RRRR, RRKK, kKRR, KkRR, KKrR, and KKRr (amino acid residues of the D configuration are designated by small letters), was studied in vivo on rats under cold and heat shock. Intranasal administration of the KKRR peptide at doses of 2–10 μg/animal 1 day before the shock was found to prevent a dramatic increase in the level of corticosterone in rat adrenal glands and blood plasma caused by the temperature effect. Amino acid substitutions in the KKRR peptide were shown to result in abrupt decrease in its activity. The peptide analogues exhibit a low stress-protective activity and had a low affinity for the ACTH receptor. [ABSTRACT FROM AUTHOR]

Familial glucocorticoid deficiency (FGD), otherwise known as hereditary unresponsiveness to ACTH, is a rare autosomal recessive disease characterized by glucocorticoid deficiency in the absence of mineralocorticoid deficiency. Mutations of the ACTH receptor, also known as the melanocortin-2 receptor (MC2R), account for approximately 25% of FGD cases. More recently a second gene, MRAP (melanocortin-2 receptor accessory protein), was identified and found to account for a further 15–20%. MRAP encodes a small single transmembrane domain protein, which is essential in the trafficking of the MC2R to the cell surface. In this review, we will firstly summarize the clinical presentation and genetic aetiology of this condition. Secondly, we will discuss how the discovery of MRAP has enhanced our understanding of the mechanisms of ACTH/MC2R action. Finally, we will explore future developments in this field. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Objective Familial glucocorticoid deficiency type I (FGD1) is a rare form of primary adrenal insufficiency resulting from recessive mutations in the ACTH receptor (MC2R, MC2R). Individuals with this condition typically present in infancy or childhood with signs and symptoms of cortisol insufficiency, but disturbances in the renin-angiotensin system, aldosterone synthesis or sodium homeostasis are not a well-documented association of FGD1. As ACTH stimulation has been shown to stimulate aldosterone release in normal controls, and other causes of hyponatraemia can occur in children with cortisol deficiency, we investigated whether MC2R changes might be identified in children with primary adrenal failure who were being treated for mineralocorticoid insufficiency. Design Mutational analysis of MC2R by direct sequencing. Patients Children ( n = 22) who had been diagnosed with salt-losing forms of adrenal hypoplasia (19 isolated cases, 3 familial), and who were negative for mutations in DAX1 (NR0B1) and SF1 (NR5A1). Results MC2R mutations were found in three individuals or kindred (I: homozygous S74I; II: novel compound heterozygous R146H/560delT; III: novel homozygous 579-581delTGT). These changes represent severely disruptive loss-of-function mutations in this G-protein coupled receptor, including the first reported homozygous frameshift mutation. The apparent disturbances in sodium homeostasis were mild, manifest at times of stress (e.g. infection, salt-restriction, heat), and likely resolved with time. Conclusions MC2R mutations should be considered in children who have primary adrenal failure with apparent mild disturbances in renin-sodium homeostasis. These children may have been misdiagnosed as having salt-losing adrenal hypoplasia. Making this diagnosis has important implications for treatment, counselling and long-term prognosis. [ABSTRACT FROM AUTHOR]

Background: Familial glucocorticoid deficiency (FGD) is a rare autosomal recessive disorder characterized by glucocorticoid deficiency, high ACTH levels and normal mineralocorticoid levels. FGD is caused due to defects in adrenocorticotropic hormone (ACTH) signaling. The defect can be caused by mutations in genes encoding the ACTH receptor (melanocortin 2 receptor) or its accessory protein. Patients: Here we report three siblings with FGD. The second in order of siblings presented at an age of 15 years with history of diffuse hyperpigmentation since childhood. Their parents were non consanguineous. The patients were hyperpigmented and taller compared with their parents. None of the siblings had ambiguous genitalia or neurological abnormalities. There was no history of tuberculosis in the family. Biochemical investigations revealed low serum cortisol (<1 µg/dl) and elevated plasma ACTH (>1250 pg/ml). Serum electrolytes, aldosterone, and plasma renin activity was normal. Based on the above mentioned data, a provisional diagnosis of FGD was made after ruling out the common causes of glucocorticoid deficiency. Conclusion: FGD is a rare autosomal recessive disorder which causes isolated glucocorticoid deficiency. Unawareness about the condition may lead to delayed diagnosis and treatment, which are associated with high rates of morbidity and mortality. Once a diagnosis is made it is easily treatable. [ABSTRACT FROM AUTHOR]

Oogenesis in zebrafish (Danio rerio) is controlled by the hypothalamus--pituitary--gonadal axis and reproductive hormones. In addition, an interference of stress hormones is known with reproductive biology. In the presented work, we aimed to explore the hypothesis that cortisol (Cort) and ACTH may affect early oogenesis in zebrafish, given the presence of the specific receptors for glucocorticoids and ACTH in the zebrafish ovary. Follicles at stages I and II were exposed in vitro to 1 μM Cort and ACTH for 48 h, then ultrastructural and molecular effects were analyzed. The comet assay demonstrated increased tail moments for Cort and ACTH treatment indicative of DNA damage. The mRNA expression of apoptotic genes (bax, bcl-2) was not altered by both treatments, but Cort increased significantly the expression of the ACTH receptor (mc2r). Cort stimulated the presence of the endoplasmic reticulum, predominantly at stage II, while ACTH induced a strong vacuolization. Viability of oocytes was not affected by both treatments and fluorescent staining (monodansylcadaverine/acridine orange) indicated a reduced quantity of autophagosomes for ACTH, and lower presence of nucleic acids in ooplasm for Cort and ACTH. Concluding, different responses were observed for stress hormones on early stages of zebrafish oocytes, which suggest a role for both hormones in the stress-mediated adverse effects on female gametogenesis. [ABSTRACT FROM AUTHOR]

Context: The prevalence of unilateral primary aldosteronism (UPA) with cortisol co-secretion varies geographically. Objective: To investigate the prevalence and clinical characteristics of UPA with cortisol co-secretion in a Chinese population. Design: Retrospective cohort study. Methods: We recruited 580 patients with UPA who underwent cosyntropin stimulation test (CST) after the 1-mg dexamethasone suppression test (DST) and retrospectively analyzed the clinical characteristics and postoperative outcomes of UPA with and without cortisol co-secretion. Results: UPA with cortisol co-secretion (1 mg DST>1.8 ug/dL) was identified in 65 of 580 (11.2%) patients. These patients were characterized by older age, longer duration of hypertension, higher concentration of plasma aldosterone and midnight cortisol, lower adrenocorticotropic hormone (ACTH) and dehydroepiandrosterone sulfate (DHEAS), larger tumor diameter, and more history of diabetes mellitus. Cortisol and aldosterone levels were higher and DHEAS level was lower in UPA with cortisol co-secretion at 0--120 min after CST. Among 342 UPA patients with KCNJ5 gene sequencing and follow-up results, the complete clinical success rate was lower in UPA with cortisol co-secretion (33.3% vs. 56.4%, P<0.05); the complete biochemical success rate and KCNJ5 mutation did not differ between the two groups. Age, tumor size, and ACTH were independent predictors of UPA with cortisol co-secretion. Sex, BMI, duration of hypertension, KCNJ5 mutation, and cortisol co-secretion were independent predictors for complete clinical success in UPA after surgery. Conclusions: UPA with cortisol co-secretion is not uncommon in China, but the clinical features were distinctly different from those without co-secretion. Cortisol co-secretion is an independent risk factor for incomplete clinical success after surgery in UPA. [ABSTRACT FROM AUTHOR]

Immune nutrition is currently used to enhance fish health by incorporating functional ingredients into aquafeeds. This study aimed to investigate the connections between tryptophan nutrition and the network that regulates the communication pathways between neuroendocrine and immune systems in European seabass (Dicentrarchus labrax). When tryptophan was supplemented in the diet of unstressed fish, it induced changes in the hypothalamic-pituitary-interrenal axis response to stress. Tryptophan-mediated effects were observed in the expression of anti-inflammatory cytokines and glucocorticoid receptors. Tryptophan supplementation decreased pro-opiomelanocortin b-like levels, that are related with adrenocorticotropic hormone and cortisol secretion. When stressed fish fed a tryptophan-supplemented diet were subjected to an inflammatory stimulus, plasma cortisol levels decreased and the expression of genes involved in the neuroendocrine response was altered. Modulatory effects of tryptophan dietary intervention on molecular patterns seem to be mediated by altered patterns in serotonergic activity. [ABSTRACT FROM AUTHOR]

Background: Cushing’s syndrome (CS) during pregnancy is a rare endocrine disorder characterized by hypercortisolism, which is significantly associated with maternal-fetal complications. Despite its rarity, CS during pregnancy may be related to a high risk of complications for both the mother and fetus.The aim of the present case study is to update the diagnostic approach to CS during pregnancy and the therapeutic strategies for this medical condition to minimize maternal-fetal complications. Methods: Here, we present two cases of CS in pregnant women, one of whom had twins. Typical clinical symptoms and signs of hypercortisolism developed at the beginning of pregnancy. The plasma cortisol diurnal rhythm of the pregnant patient was absent. CS was confirmed by cortisol and adrenocorticotropic hormone (ACTH) assessment, as well as imaging examination. We investigated the changes in the hypothalamic-pituitary-adrenal axis during normal pregnancy and the etiology, diagnosis and treatment of CS during pregnancy. Conclusion: Due to the associated risks of laparoscopic adrenalectomy,it is uncertain whether this treatment significantly decreases overall maternal mortality. Additional observational research and validation through randomized controlled trials (RCTs) are required. We advise that CS in pregnant women be diagnosed and treated by experienced teams in relevant departments and medical centers. [ABSTRACT FROM AUTHOR]

Adverse environmental conditions before birth are known to programme adult metabolic and endocrine phenotypes in several species. However, whether increments in fetal cortisol concentrations of the magnitude commonly seen in these conditions can cause developmental programming remains unknown. Thus, this study investigated the outcome of physiological increases in fetal cortisol concentrations on glucose-insulin dynamics and pituitary-adrenal function in adult sheep. Compared with saline treatment, intravenous fetal cortisol infusion for 5 days in late gestation did not affect birthweight but increased lamb body weight at 1-2 weeks after birth. Adult glucose dynamics, insulin sensitivity and insulin secretion were unaffected by prenatal cortisol overexposure, assessed by glucose tolerance tests, hyperinsulinaemic-euglycaemic clamps and acute insulin administration. In contrast, prenatal cortisol infusion induced adrenal hypo-responsiveness in adulthood with significantly reduced cortisol responses to insulin-induced hypoglycaemia and exogenous adrenocorticotropic hormone (ACTH) administration relative to saline treatment. The area of adrenal cortex expressed as a percentage of the total cross-sectional area of the adult adrenal gland was also lower after prenatal cortisol than saline infusion. In adulthood, basal circulating ACTH but not cortisol concentrations were significantly higher in the cortisol than saline-treated group. The results show that cortisol overexposure before birth programmes pituitary-adrenal development with consequences for adult stress responses. Physiological variations in cortisol concentrations before birth may, therefore, have an important role in determining adult phenotypical diversity and adaptability to environmental challenges. [ABSTRACT FROM AUTHOR]

Synthetic corticosteroids are used widely for the treatment of a variety of diseases of the mouth. However, little is known as to whether the oral mucosa is able to modulate the local concentration of active corticosteroids or to produce steroids de novo. This has important clinical implications, because tissue-specific regulation of glucocorticoids is a key determinant of the clinical efficacy of these drugs. In the present study, we show that oral fibroblasts and keratinocytes expressed ACTH receptor (MC2R), glucocorticoid receptor (GR), and 11β-hydroxysteroid dehydrogenases (11β-HSDs). Unlike keratinocytes, fibroblasts lacked 11β-HSD2 and could not effectively deactivate exogenously administered cortisol. However, both cell types were able not only to activate cortisone into the active form cortisol, but also to synthesize cortisol de novo following stimulation with ACTH. 11β-HSD2, the enzyme controlling cortisol deactivation, exhibited different patterns of expression in normal (squamous epithelium and salivary glands) and diseased oral mucosa (squamous cell carcinoma and mucoepidermoid carcinoma). Blocking of endogenous cortisol catabolism in keratinocytes with the 11β-HSD2 inhibitor 18β-glycyrrhetinic acid mimicked the effect of exogenous administration of hydrocortisone and partially prevented the detrimental effects induced by pemphigus vulgaris sera. Analysis of the data demonstrates that a novel, non-adrenal glucocorticoid system is present in the oral mucosa that may play an important role in disease. [ABSTRACT FROM PUBLISHER]

Summary Objective The aim of this study was to investigate the effects of transsphenoidal surgery (TS) on the adrenal sensitivity to ACTH (adrenocorticotropin) stimulation in patients with Cushing's disease (CD). Methods We measured the cortisol response to 1 μg synthetic ACTH (1-24) 6 days after pituitary surgery in 45 patients with CD. Mean follow-up period was 56·5 months (SE 4·7). Results In 24 of 28 patients in sustained remission after pituitary surgery, peak cortisol concentrations below 774 n m (28·0 μg/dl) were recorded after stimulation with 1 μg synthetic ACTH (86%). Two patients with recurrent disease after initial remission (late relapse) also showed ACTH-stimulated peak cortisol levels below 774 n m. Fourteen of 15 patients with persistent CD after surgery (early failure) showed absolute peak cortisol levels >774 n m in response to ACTH stimulation. Conclusion Patients in remission after pituitary surgery for CD showed a rapid decrease of adrenal responsiveness to exogenous ACTH stimulation. This phenomenon may be explained by ACTH-receptor down-regulation in the adrenal cortex after complete removal of the pituitary corticotroph adenoma. In our study, the postoperative low-dose ACTH stimulation test had a sensitivity of 93% and a specificity of 87% in predicting immediate remission of CD after pituitary surgery. [ABSTRACT FROM AUTHOR]

Familial glucocorticoid deficiency (FGD) or hereditary unresponsiveness to adrenocorticotropin (ACTH) is an autosomal recessive disorder characterized by isolated glucocorticoid deficiency associated with normal mineralocorticoid secretion. Mutations in genes encoding either ACTH receptor or melanocortin 2 receptor accessory protein are responsible for the disease in about 50% of cases, named FGD type 1 and type 2, respectively. Patients may present with hyperpigmentation, recurrent infections, failure to thrive, hypoglycemic seizures, and coma in infancy or early childhood. Here we report the case of a 17-day-old newborn diagnosed with FGD type 1 who presented with hyperbilirubinemia and hyperpigmentation, a sign which was erroneously assumed to be due to prolonged phototherapy by the referring physician. Hormone analysis showed low cortisol and high ACTH levels with normal serum electrolytes and renin-aldosterone axis. Genetic analysis revealed a novel homozygous melanocortin 2 receptor mutation p.Leu225Arg in the patient. The healthy parents were heterozygous for the mutation. Copyright © 2011 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Corticotropin releasing hormone (CRH) has been detected in the adrenal gland of many species and may be involved in regulation of glucocorticoid secretion. In cultured human fetal adrenal definitive/transitional zone cells, CRH upregulates the adrenocorticotropic hormone (ACTH) receptor and steroidogenic enzymes and is blocked by the selective CRH type 1 receptor (CRH1) antagonist, antalarmin. Based on these findings and evidence that antalarmin infusion into sheep suppressed prepartum increases in cortisol, we hypothesized that antalarmin would influence adrenal cortisol secretion. Antalarmin strongly attenuated ACTH and forskolin (FSK)-stimulated cortisol and cyclic adenosine monophosphate (cAMP) release from cultured ovine adrenocortical cells but did not prevent ACTH binding to cells or ACTH-induced proliferation in adult cells. Corticotropin releasing hormone was minimally effective as a secretagogue but increased the cortisol response to subsequent ACTH. These results suggest that antalarmin attenuates ACTH-induced cortisol secretion from cultured ovine adrenal cortical cells at a site distal to the ACTH receptor. Although CRH may modulate the secretory response to ACTH, it is probably not a direct cortisol secretagogue in the sheep. [ABSTRACT FROM AUTHOR]

The adrenocorticotropin (ACTH) receptor (melanocortin 2 receptor, or MC2R) is the smallest G-protein-coupled receptor that, when activated by the peptide hormone ACTH, stimulates cAMP production and adrenal steroidogenesis. Receptor expression is dependent on a specific membrane trafficking process involving an accessory protein (melanocortin 2 receptor accessory protein, or MRAP) and other unidentified components. In an attempt to discover novel receptor interacting proteins, the C-terminal tail of the MC2R was used to screen a mouse adrenal Y6 cell cDNA library using the bacterial two-hybrid system. This identified the nucleoporin Nup 50 (Npap60) as the major full-length interacting protein. Interaction was confirmed by a GST pulldown assay and by coimmunoprecipitation in human H295R cells (which express both proteins endogenously). Deletion analysis identified the region between residues 143 and 466 in Nup50 as being required for interaction with the MC2R. Stimulation of H295R cells with ACTH (10-6 M) was followed by a gradual translocation of the Nup50-MC2R complex from the membrane to the nucleus after 30 min. This time course is most consistent with MC2R internalization dynamics and may suggest a novel role for Nup50. [ABSTRACT FROM AUTHOR]

The source of aldosterone in 30–40% of patients with primary hyperaldosteronism (PA) is unilateral aldosterone-producing adenoma (APA). The mechanisms causing elevated aldosterone production in APA are unknown. Herein, we examined the expression of G-protein-coupled receptors (GPCRs) in APA and demonstrated that when compared with normal adrenals, there is a general elevation of certain GPCR in many APA and/or ectopic expression of GPCR in others. RNA samples from normal adrenals (n = 5), APAs (n = 10), and cortisol-producing adenomas (CPAs; n = 13) were used on 15 genomic expression arrays, each of which included 223 GPCR transcripts presented in at least 1 out of 15 of the independent microarrays. The array results were confirmed using real-time RT-PCR (qPCR). Four GPCR transcripts exhibited a statistically significant increase that was greater than threefold when compared with normal adrenals, suggesting a general increase in expression when compared with normal adrenal glands. Four GPCR transcripts exhibited a > 15-fold increase of expression in one or more of the APA samples when compared with normal adrenals. qPCR analysis confirmed array data and found the receptors with the highest fold increase in APA expression to be LH receptor, serotonin receptor 4, GnRH receptor, glutamate receptor metabotropic 3, endothelin receptor type B-like protein, and ACTH receptor. There are also sporadic increased expressions of these genes in the CPAs. Together, these findings suggest a potential role of altered GPCR expression in many cases of PA and provide candidate GPCR for further study. [ABSTRACT FROM AUTHOR]

We examined the cross-regulation of signaling between ACTH-and platelet-activating factor (PAF)-mediated steroidogenesis in the perfused guinea pig adrenal gland. Our method of in situ perfusion using an artificial medium can evaluate whether cortisol secretion in response to ACTH and PAF is interactive. Treating adrenal glands with 100 pg/ml ACTH diminished the subsequent cortisol response to 10 nM PAF. By contrast, PAF resulted in subsequent potentiation of ACTH-induced cortisol secretion. A mixture of 50 µM L--1-oleoyl-2-acetyl-sn-glycerol (OAG), an activator of protein kinase C (PKC), and 3.3 µM calcium ionophore (A23187), or 10 µM forskolin (FRK) diminished the cortisol response to PAF, whereas that to ACTH was unaffected. Each of PAF, ACTH, or FRK eliminated the cortisol response to OAG plus A23187, whereas that to FRK was unaffected. These data show that the protein kinase A (PKA)-dependent processes activated by ACTH or FRK can interfere with PAF-induced signal transduction at receptor and post-receptor levels. In contrast, PKC-dependent processes activated by PAF promoted ACTH-signaling at receptor and post-receptor level. Cross-regulation between processes activated by PAF receptor–PKC and by ACTH receptor–PKA might function in the multifactorial regulation of adrenocortical steroidogenesis. [ABSTRACT FROM AUTHOR]

Fetal exposure to synthetic glucocorticoids in sheep results in increased fetal hypothalamic-pituitary-adrenal (HPA) activity persisting to one year of age. We aimed to determine the effects of single or repeated maternal or fetal beta- methasone injections on offspring HPA activity at 2 and 3 yr of age and whether changes in adrenal mediators of steroidogenesis contribute to changes in pituitary-adrenal function. Pregnant ewes or their fetuses received either repeated intramuscular saline or betamethasone injections (0.5 mg/kg) at 104, 111, 118, and 124 days of gestation (dG) or a single betamethasone injection at 104 dG followed by saline at 111, 118, and 124 dG. Offspring were catheterized at 2 and 3 yr of age and given corticotrophin-releasing hormone + arginine vasopressin challenges. Adrenal tissue was collected for quantitative RT-PCR mRNA determination at 3.5 yr of age. In 2-yr-old offspring, maternal betamethasone injections did not alter basal ACTH or cortisol levels, but repeated injections elevated ACTH responses. At 3 yr of age, basal ACTH was elevated, and both basal and stimulated cortisol levels were suppressed by repeated maternal injections. Basal and stimulated cortisol-to-ACTH ratios and basal cortisol-to-cytochrome P-450 17α-hydroxylase (P450c17) mRNA ratios were suppressed by repeated injections. Repeated fetal betamethasone injections attenuated basal ACTH and cortisol levels in offspring at 2 but not 3 yr of age. Plasma changes were not associated with altered adrenal P450c17, ACTH receptor, β-hydroxysteroid dehydrogenase, or glucocorticoid receptor mRNA levels. These data suggest that maternal, but not fetal, betamethasone administration results in adrenal suppression in adulthood. [ABSTRACT FROM AUTHOR]

ACTH-resistance in four mutant derivatives of a mouse adrenocortical tumor cell line results from a defect that reduces the activity of steroidogenic factor-1 (SF1) thereby preventing expression of the ACTH receptor and other SF1-dependent genes. The SF1 genes from these mutants contain a sequence difference that changes an Ala to Ser at codon 172. Steroidogenic factor-1[sup S172] represents a polymorphism rather than a spontaneous mutation since the two forms of SF1, SF1[sup A172], and SF1[sup S172], can be traced to the hybrid mouse strain (C57L/J × A/HeJ) from which the original adrenal tumor was derived. The SF1[sup S172] allele is amplified in three of the four mutant clones together with the neighboring genes germ cell nuclear factor and LIM homeobox2. The two forms of SF1 had only modest differences in transcriptional activity in reporter gene assays, suggesting that the SF1 polymorphism per se is not directly responsible for the loss of mc2r expression. Rather, ACTH resistance in this family of adrenocortical tumor cell mutants may be due to a closely linked gene on the SF1[sup S172] allele. Mouse strains with reportedly high steroidogenic capacity (C57B1/6J, C57B1/10J) also have the SF1[sup A172] allele while mouse strains with low steroidogenic capacity (C3H/HeJ, DBA/2J) have the SF1[sup S172] allele. These latter observations suggest that the two SF1 alleles also may be markers of steroidogenic potential among mouse strains. [ABSTRACT FROM AUTHOR]

Comments on the paper describing a patient with Cushing's syndrome due to ectopic ACTH precursor production by pancreatic tumor. Cause of the hypercortisolemia; Overestimation on reported levels of ACTH; Absence of biological evidence of ACTH precursors at the ACTH receptor.

Nucleobindin-derived peptides, nesfatin-1 [NESF-1] and nesfatin-1-like-peptide [NLP] have diverse roles in endocrine and metabolic regulation. While both peptides showed a stimulatory effect on the synthesis of proopiomelanocortin (POMC), the adrenocorticotropic hormone (ACTH) precursor in mouse corticotrophs, whether NESF-1 and NLP have any direct effect on glucocorticoid [GC] synthesis in the adrenal cortex remains unknown. The main aim of this study was to determine if NESF-1 and/or NLP act directly on adrenal cortex cells to regulate cortisol synthesis in vitro. Whether NLP injection affects stress-hormone gene expression in the adrenal gland and pituitary in vivo in mice was also assessed. In addition, cortisol synthetic pathway in Nucb1 knockout mice was studied. Human adrenal cortical [H295R] cells showed immunoreactivity for both NUCB1/NLP and NUCB2/NESF-1. NLP and NESF-1 decreased the abundance of steroidogenic enzyme mRNAs, and cortisol synthesis and release through the AC/PKA/CREB pathway in H295R cells. Similarly, intraperitoneal injection of NLP in mice decreased the expression of enzymes involved in glucocorticoid (GC) synthesis in the adrenal gland while increasing the expression of Pomc, Pcsk1 and Crhr1 in the pituitary. Moreover, the melanocortin 2 receptor (Mc2r) mRNA level was enhanced in the adrenal gland samples of NLP injected mice. However, the global genetic disruption in Nucb1 did not affect most steroidogenic enzyme mRNAs, and Pomc, Pcsk2 and Crhr1 mRNAs in mice adrenal gland and pituitary gland, respectively. Collectively, these data provide the first evidence for a direct inhibition of cortisol synthesis and secretion by NLP and NESF-1. NUCB peptides might still elicit a net stimulatory effect on GC synthesis and secretion through their positive effects on ACTH-MC2R pathway in the pituitary. [ABSTRACT FROM AUTHOR]

Background: Hyperuricemia is a known risk factor of lipid metabolism disorder. However, the mechanisms have not been fully understood. Methods: The serum samples from hyperuricemia subjects were used to analyze the correlation between serum uric acid and clinical characteristics. Hyperuricemia mice induced by potassium oxonate (PO) and adenine were used to explore glucocorticoid metabolism. Results: In hyperuricemia patients, the levels of serum uric acid were positively correlated with the levels of g-glutamyltransferase, associated with a cortisol metabolism disorder. In hyperuricemia state, the adrenal glands failed to respond to adrenocorticotropic hormone properly, leading to low cortisol, but not corticosterone production, and decreased mRNA levels of aldosterone synthase, 11b-hydroxylase, and 3b-hydroxysteroid dehydrogenase 1, three key enzymes for cortisol synthesis. The expression of both hepatic 5a-reductase and renal 11b-hydroxysteroid dehydrogenase 2 was significantly reduced, which led to low cortisol clearance. We denominated this cortisol metabolism disorder in hyperuricemia as pseudohypoadrenalism (PHAL). Conclusion: PHAL increased exposure to the bioavailable cortisol in the liver, leading to local amplification of the biological action of corticosteroids. Unregulated biosynthesis pathway of bile acid expanded bile acid pool, and further aggravated cholestatic liver injury [ABSTRACT FROM AUTHOR]