Mediatory role of the central NPY, melanocortine and corticotrophin systems on phoenixin-14 induced hyperphagia in neonatal chicken.

Animal research indicates the neuropeptide Y (NPY), corticotrophin and melanocortin systems have a mediatory role in reward, however, how these substances interact with phenytoin-14 (PNX-14) induced food intake in birds remains to be identified. Accordingly, in this research eight tests were carried out to investigate the potential interactions of the NPY, melanocortin, as well as corticotrophin systems with PNX-14 on food consumption in neonatal chickens. In the first experiment, chickens were intracerebroventricular (ICV) injected with phosphate-buffered saline (PBS) and PNX-14 (0.8, 0.16, and 3.2 nmol). In second experiment, PBS, the antagonist of CRF1/CRF2 receptors (astressin-B, 30 µg) and PNX-14 + astressin-B were injected. In the rest of the experiments chicken received astressin2-B (CRF2 receptor antagonist; 30 µg), SHU9119 (MCR3/MCR4 receptor antagonist, 0.5nomol), MCL0020 (MCR4 receptor agonist, 0.5 nmol), B5063 (NPY1 receptor antagonist, 1.25 µg), SF22 (NPY2 receptor antagonist, 1.25 µg) and SML0891 (NPY5 receptor antagonist, 1.25 µg) rather than astressin-B. Then, cumulative intake of food was recorded for 2 h. Based on the findings, PNX-14 (0.16 and 3.2 nmol) led to increment in food consumption compared with the control (P < 0.05). Co-administration of the PNX-14 and astressin-B promoted PNX-14-induced hyperphagia (P < 0.05). Co-injection of the PNX-14 + astressin2-B potentiated hyperphagia PNX-14 (P < 0.05). Co-injection of PNX-14 + B5063 inhibited the effects of the PNX-14 (P < 0.05). The co-administration of the PNX-14 and SML0891 potentiated hypophagic effects of the PNX-14 (P < 0.05). The results showed that PNX-14-induced hyperphagia mediates via NPY1, NPY5, and CRF1/CRF2 receptors in neonatal chickens.

Acute social defeat stress upregulates gonadotrophin inhibitory hormone and its receptor but not corticotropin-releasing hormone and ACTH in the Male Nile Tilapia (Oreochromis niloticus).

Stress impairs the hypothalamic-pituitary-gonadal (HPG) axis, probably through its influence on the hypothalamic-pituitary-adrenal (= interrenals in the teleost, HPI) axis leading to reproductive failures. In this study, we investigated the response of hypothalamic neuropeptides, gonadotropin-inhibitory hormone (GnIH), a component of the HPG axis, and corticotropin-releasing hormone (CRH) a component of the HPI axis, to acute social defeat stress in the socially hierarchical male Nile tilapia (Oreochromis niloticus). Localization of GnIH cell bodies, GnIH neuronal processes, and numbers of GnIH cells in the brain during acute social defeat stress was studied using immunohistochemistry. Furthermore, mRNA levels of GnIH and CRH in the brain together with GnIH receptor, gpr147, and adrenocorticotropic hormone (ACTH) in the pituitary were quantified in control and socially defeated fish. Our results show, the number of GnIH-immunoreactive cell bodies and GnIH mRNA levels in the brain and the levels of gpr147 mRNA in the pituitary significantly increased in socially defeated fish. However, CRH and ACTH mRNA levels did not change during social defeat stress. Further, we found glucocorticoid type 2b receptor mRNA in laser captured immunostained GnIH cells. These results show that acute social defeat stress activates GnIH biosynthesis through glucocorticoid receptors type 2b signalling but does not change the CRH and ACTH mRNA expression in the tilapia, which could lead to temporary reproductive dysfunction.

Acupuncture for Pain Management: Molecular Mechanisms of Action.

Acupuncture reduces pain by activating specific areas called acupoints on the patient's body. When these acupoints are fully activated, sensations of soreness, numbness, fullness, or heaviness called De qi or Te qi are felt by clinicians and patients. There are two kinds of acupuncture, manual acupuncture and electroacupuncture (EA). Compared with non-acupoints, acupoints are easily activated on the basis of their special composition of blood vessels, mast cells, and nerve fibers that mediate the acupuncture signals. In the spinal cord, EA can inhibit glial cell activation by down-regulating the chemokine CX3CL1 and increasing the anti-inflammatory cytokine interleukin-10. This inhibits P38 mitogen-activated protein kinase and extracellular signal-regulated kinase pathways, which are associated with microglial activation of the C-Jun N-terminal kinase signaling pathway and subsequent astrocyte activation. The inactivation of spinal microglia and astrocytes mediates the immediate and long-term analgesic effects of EA, respectively. A variety of pain-related substances released by glial cells such as the proinflammatory cytokines tumor necrosis factor [Formula: see text], interleukin-1[Formula: see text], interleukin-6, and prostaglandins such as prostaglandins E2 can also be reduced. The descending pain modulation system in the brain, including the anterior cingulated cortex, the periaqueductal gray, and the rostral ventromedial medulla, plays an important role in EA analgesia. Multiple transmitters and modulators, including endogenous opioids, cholecystokinin octapeptide, 5-hydroxytryptamine, glutamate, noradrenalin, dopamine, [Formula: see text]-aminobutyric acid, acetylcholine, and orexin A, are involved in acupuncture analgesia. Finally, the "Acupuncture [Formula: see text]" strategy is introduced to help clinicians achieve better analgesic effects, and a newly reported acupuncture method called acupoint catgut embedding, which injects sutures made of absorbable materials at acupoints to achieve long-term effects, is discussed.

Adrenocorticotropic Hormone and Cyclic Adenosine Monophosphate are Involved in the Control of Shark Bioluminescence.

Among Etmopteridae and Dalatiidae, luminous species use hormonal control to regulate bioluminescence. Melatonin (MT) triggers light emission and, conversely, alpha melanocyte-stimulating hormone (α-MSH) actively reduces ongoing luminescence. Prolactin (PRL) acts differentially, triggering light emission in Etmopteridae and inhibiting it in Dalatiidae. Interestingly, these hormones are also known as regulators of skin pigment movements in vertebrates. One other hormone, the adrenocorticotropic hormone (ACTH), also members of the skin pigmentation regulators, is here pharmacologically tested on the light emission. Results show that ACTH inhibits luminescence in both families. Moreover, as MT and α-MSH/ACTH receptors are members of the G-protein coupled receptor (GPCR) family, we investigated the effect of hormonal treatments on the cAMP level of photophores through specific cAMP assays. Our results highlight the involvement of ACTH and cAMP in the control of light emission in sharks and suggest a functional similarity between skin pigment migration and luminescence control, this latter being mediated by pigment movements in the light organ-associated iris-like structure cells.

Enkephalins and ACTH in the mammalian nervous system.

The pentapeptides methionine-enkephalin and leucine-enkephalin belong to the opioid family of peptides, and the non-opiate peptide adrenocorticotropin hormone (ACTH) to the melanocortin peptide family. Enkephalins/ACTH are derived from pro-enkephalin, pro-dynorphin or pro-opiomelanocortin precursors and, via opioid and melanocortin receptors, are responsible for many biological activities. Enkephalins exhibit the highest affinity for the δ receptor, followed by the µ and κ receptors, whereas ACTH binds to the five subtypes of melanocortin receptor, and is the only member of the melanocortin family of peptides that binds to the melanocortin-receptor 2 (ACTH receptor). Enkephalins/ACTH and their receptors exhibit a widespread anatomical distribution. Enkephalins are involved in analgesia, angiogenesis, blood pressure, embryonic development, emotional behavior, feeding, hypoxia, limbic system modulation, neuroprotection, peristalsis, and wound repair; as well as in hepatoprotective, motor, neuroendocrine and respiratory mechanisms. ACTH plays a role in acetylcholine release, aggressive behavior, blood pressure, bone maintenance, hyperalgesia, feeding, fever, grooming, learning, lipolysis, memory, nerve injury repair, neuroprotection, sexual behavior, sleep, social behavior, tissue growth and stimulates the synthesis and secretion of glucocorticoids. Enkephalins/ACTH are also involved in many pathologies. Enkephalins are implicated in alcoholism, cancer, colitis, depression, heart failure, Huntington's disease, influenza A virus infection, ischemia, multiple sclerosis, and stress. ACTH plays a role in Addison's disease, alcoholism, cancer, Cushing's disease, dermatitis, encephalitis, epilepsy, Graves' disease, Guillain-Barré syndrome, multiple sclerosis, podocytopathies, and stress. In this review, we provide an updated description of the enkephalinergic and ACTH systems.

[Hypercorticism during streptozotocin diabetes and mifepristone administration: the role of cyclic adenosine monophosphate]. / Giperkortitsizm pri streptozototsinovom diabete i vvedenii mifepristona: rol' tsiklicheskogo adenozinmonofosfata.

It was studed basal and ACTH-stimulated production of cyclic adenosine monophosphate (cAMP) and corticosteroid hormones (progesterone and corticosterone) in rat adrenals in vitro under streptozotocin diabetes, in conditions of mifepristone administration and their combination. It was shown that in streptozotocin diabetes animals, both the basal and adrenocorticotropic hormone (ACTH) stimulated cAMP production significantly increased; this was accompanied by the increase in basal and ACTH-stimulated progesterone and corticosterone production in rat adrenals in vitro. Repeated administration of mifepristone to control and diabetic rats caused an increase mainly in ACTH-stimulated production of the main glucocorticoid hormone, corticosterone, without additional changes in the cAMP level. The results obtained suggest activation of two mechanisms of steroidogenesis enhancement in experimental animals. In rats with streptozotocin diabetes, both basal and ACTH-stimulated activity of all stages of steroidogenesis increase, which is mediated by the increased formation of cAMP as second messenger mediating the ACTH action on adrenocortical cells. Prolonged administration of mifepristone to control and diabetic rats resulted in increased activity of only late stages of steroidogenesis with predominant elevation of synthesis of physiologically active hormone corticosterone without additional changes in cAMP production level.

Models in neuroendocrinology.

The neuroendocrine systems of the hypothalamus are critical for survival and reproduction, and are highly conserved throughout vertebrate evolution. Their roles in controlling body metabolism, growth and body composition, stress, electrolyte balance and reproduction have been intensively studied, and have yielded a rich crop of original and challenging insights into neuronal function, insights that circumscribe a vision of the brain that is quite different from conventional views. Despite the diverse physiological roles of pituitary hormones, most are secreted in a pulsatile pattern, but arising through a variety of mechanisms. An important exception is vasopressin which uses bursting neural activity, but produces a graded secretion response to osmotic pressure, a sustained robust linear response constructed from noisy, nonlinear components. Neuroendocrine systems have many features such as multiple temporal scales and nonlinearity that make their underlying mechanisms hard to understand without mathematical modelling. The models presented here cover the wide range of temporal scales involved in these systems, including models of single cell electrical activity and calcium dynamics, receptor signalling, gene expression, coordinated activity of neuronal networks, whole-organism hormone dynamics and feedback loops, and the menstrual cycle. Many interesting theoretical approaches have been applied to these systems, but important problems remain, at the core the question of what is the true advantage of pulsatility.

Pterostilbene Decreases the Antioxidant Defenses of Aggressive Cancer Cells In Vivo: A Physiological Glucocorticoids- and Nrf2-Dependent Mechanism.

AIMS: Polyphenolic phytochemicals have anticancer properties. However, in mechanistic studies, lack of correlation with the bioavailable concentrations is a critical issue. Some reports had suggested that these molecules downregulate the stress response, which may affect growth and the antioxidant protection of malignant cells. Initially, we studied this potential underlying mechanism using different human melanomas (with genetic backgrounds correlating with most melanomas), growing in nude mice as xenografts, and pterostilbene (Pter, a natural dimethoxylated analog of resveratrol). RESULTS: Intravenous administration of Pter decreased human melanoma growth in vivo. However, Pter, at levels measured within the tumors, did not affect melanoma growth in vitro. Pter inhibited pituitary production of the adrenocorticotropin hormone (ACTH), decreased plasma levels of corticosterone, and thereby downregulated the glucocorticoid receptor- and nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-dependent antioxidant defense system in growing melanomas. Exogenous corticosterone or genetically induced Nrf2 overexpression in melanoma cells prevented the inhibition of tumor growth and decreased antioxidant defenses in these malignant cells. These effects and mechanisms were also found in mice bearing different human pancreatic cancers. Glutathione depletion (selected as an antimelanoma strategy) facilitated the complete elimination by chemotherapy of melanoma cells isolated from mice treated with Pter. INNOVATION: Although bioavailability-related limitations may preclude direct anticancer effects in vivo, natural polyphenols may also interfere with the growth and defense of cancer cells by downregulating the pituitary gland-dependent ACTH synthesis. CONCLUSIONS: Pter downregulates glucocorticoid production, thus decreasing the glucocorticoid receptor and Nrf2-dependent signaling/transcription and the antioxidant protection of melanoma and pancreatic cancer cells. Antioxid. Redox Signal. 24, 974-990.

Visinin-like peptide 1 in adrenal gland of the rat. Gene expression and its hormonal control.

VSNL1 encodes the calcium-sensor protein visinin-like 1 and was identified previously as an upregulated gene in a sample set of aldosterone-producing adenomas. Recently, by means of microarray studies we demonstrated high expression of Vsnl1 gene in rat adrenal zona glomerulosa (ZG). Only scanty data are available on the role of this gene in adrenal function as well as on regulation of its expression by factors affecting adrenal cortex structure and function. Therefore we performed relevant studies aimed at clarifying some of the above issues. By Affymetrix(®) Rat Gene 1.1 ST Array Strip, QPCR and immunohistochemistry we demonstrated that expression levels of Vsnl1 in the rat adrenal ZG are notably higher than in the fasciculata/reticularis zone. In QPCR assay this difference was approximately 10 times higher. Expression of this gene in the rat adrenal gland or adrenocortical cells was acutely down regulated by ACTH, while chronic administration of corticotrophin or dexamethasone did not change Vsnl1 mRNA levels. In enucleation-induced adrenocortical regeneration expression levels of both Vsnl1 and Cyp11b2 were notably lowered and positively correlated. Despite these findings, the physiological significance of adrenal Vsnl1 remains unclear, and requires further investigation.

Reduced nocturnal ACTH-driven cortisol secretion during critical illness.

Recently, during critical illness, cortisol metabolism was found to be reduced. We hypothesize that such reduced cortisol breakdown may suppress pulsatile ACTH and cortisol secretion via feedback inhibition. To test this hypothesis, nocturnal ACTH and cortisol secretory profiles were constructed by deconvolution analysis from plasma concentration time series in 40 matched critically ill patients and eight healthy controls, excluding diseases or drugs that affect the hypothalamic-pituitary-adrenal axis. Blood was sampled every 10 min between 2100 and 0600 to quantify plasma concentrations of ACTH and (free) cortisol. Approximate entropy, an estimation of process irregularity, cross-approximate entropy, a measure of ACTH-cortisol asynchrony, and ACTH-cortisol dose-response relationships were calculated. Total and free plasma cortisol concentrations were higher at all times in patients than in controls (all P < 0.04). Pulsatile cortisol secretion was 54% lower in patients than in controls (P = 0.005), explained by reduced cortisol burst mass (P = 0.03), whereas cortisol pulse frequency (P = 0.35) and nonpulsatile cortisol secretion (P = 0.80) were unaltered. Pulsatile ACTH secretion was 31% lower in patients than in controls (P = 0.03), again explained by a lower ACTH burst mass (P = 0.02), whereas ACTH pulse frequency (P = 0.50) and nonpulsatile ACTH secretion (P = 0.80) were unchanged. ACTH-cortisol dose response estimates were similar in patients and controls. ACTH and cortisol approximate entropy were higher in patients (P ≤ 0.03), as was ACTH-cortisol cross-approximate entropy (P ≤ 0.001). We conclude that hypercortisolism during critical illness coincided with suppressed pulsatile ACTH and cortisol secretion and a normal ACTH-cortisol dose response. Increased irregularity and asynchrony of the ACTH and cortisol time series supported non-ACTH-dependent mechanisms driving hypercortisolism during critical illness.

Skeletal maturation in children with Cushing syndrome is not consistently delayed: the role of corticotropin, obesity, and steroid hormones, and the effect of surgical cure.

OBJECTIVE: To assess skeletal maturity by measuring bone age (BA) in children with Cushing syndrome (CS) before and 1-year after transsphenoidal surgery or adrenalectomy, and to correlate BA with hormone levels and other measurements. STUDY DESIGN: This case series conducted at the National Institutes of Health Clinical Center included 93 children with Cushing disease (CD) (43 females; mean age, 12.3 ± 2.9 years) and 31 children with adrenocorticotropic hormone-independent CS (AICS) (22 females, mean age 10.3 ± 4.5 years). BA was obtained before surgery and at follow-up. Outcome measures were comparison of BA in CD vs AICS and analysis of the effects of hypercortisolism, insulin excess, body mass index, and androgen excess on BA. RESULTS: Twenty-six of the 124 children (21.0%) had advanced BA, compared with the expected general population prevalence of 2.5% (P < .0001). Only 4 of 124 (3.2%) had delayed BA. The majority of children (76%) had normal BA. The average BA z-score was similar in the children with CD and those with AICS (0.6 ± 1.4 vs 0.5 ± 1.8; P = .8865). Body mass index SDS and normalized values of dehydroepiandrosterone, dehydroepiandrosterone sulfate, androsteonedione, estradiol, and testosterone were all significantly higher in the children with advanced BA vs those with normal or delayed BA. Fifty-nine children who remained in remission from CD had follow-up BA 1.2 ± 0.3 years after transsphenoidal surgery, demonstrating decreased BA z-score (1.0 ± 1.6 vs 0.3 ± 1.4; P < .0001). CONCLUSION: Contrary to common belief, endogenous CS in children appears to be associated with normal or even advanced skeletal maturation. When present, BA advancement in CS is related to obesity, insulin resistance, and elevated adrenal androgen levels and aromatization. This finding may have significant implications for treatment decisions and final height predictions in these children.

Natural killer cell cytotoxicity, cytokine and neuroendocrine responses to opioid receptor blockade during prolonged restraint in pigs.

This study evaluated porcine natural killer cell cytotoxicity (NKCC), plasma cytokines including interleukin (IL) 1ß, IL-6, IL-10, IL-12 and tumor necrosis factor-α and plasma stress-related hormones including prolactin (PRL), growth hormone (GH), ß-endorphin (BEND), ACTH and cortisol (COR) during a 4h restraint and recovery phase after saline or naloxone (1mg/kg BW) administration. The restraint preceded with saline altered NKCC and IL-12 concentration (an early from 15 to 60 min increase followed by a decrease) and increased other measured cytokines and hormones concentrations. Naloxone pretreatment blocked the suppressive effects of the restraint on NKCC and IL-12 and altered IL-10, IL-6, TNF-α, PRL and ACTH concentrations. Furthermore, in naloxone-injected pigs, a positive correlation was found between NKCC and all measured cytokines (with the exception of IL-6) and BEND, ACTH and COR. Results suggest that naloxone-sensitive opioid pathways could influence the mechanisms underlying the immune system (including NKCC) response during stress.

Study of the signaling function of sulfiredoxin and peroxiredoxin III in isolated adrenal gland: unsuitability of clonal and primary adrenocortical cells.

Members of the peroxiredoxin (Prx) family of antioxidant enzymes are inactivated via hyperoxidation of the active site cysteine by the substrate H2O2 and are reactivated via an ATP-consuming process catalyzed by sulfiredoxin (Srx). PrxIII is reversibly inactivated by H2O2 produced by cytochrome P450 11B1 (CYP11B1) in mitochondria during corticosterone synthesis in the adrenal gland of mice injected with adrenocorticotropic hormone (ACTH). Inactivation of PrxIII triggers a sequence of events including accumulation of H2O2, activation of p38 mitogen-activated kinase (MAPK), inhibition of cholesterol transfer, and suppression of corticosterone synthesis. Srx expression is significantly induced by ACTH injection. The coupling of CYP11B1 activity to PrxIII inactivation and Srx induction provides a feedback regulatory mechanism for steroidogenesis that functions independently of the hypothalamic-pituitary-adrenal axis. Furthermore, the PrxIII-Srx regulatory pathway is critical for the circadian rhythm of corticosterone production. Although adrenocortical tumor cell lines such as Y-1 and H295R have been used extensively for studying the mechanism of steroidogenesis, those clonal cells were found to be unsuitable as an in vitro model for redox signaling because the amount of Srx in the cell lines is much higher than that in mouse adrenal gland and not affected by ACTH stimulation. Furthermore, the levels of PrxIII in the clonal cells are greatly reduced compared to that in the adrenal gland, and ACTH does not induce PrxIII hyperoxidation in the clonal cells. Primary adrenocortical cells isolated from the mouse adrenal gland were also found to be an invalid model because Srx levels are increased, along with decreased levels of hyperoxidized PrxIII, soon after isolation of these cells. Organ culture system is, however, appropriate for studying the PrxIII-Srx regulatory function as the levels of hyperoxidized PrxIII and Srx in the adrenal glands maintained overnight in culture medium are not changed.

Neuropeptides and central control of sexual behaviour from the past to the present: a review.

Of the numerous neuropeptides identified in the central nervous system, only a few are involved in the control of sexual behaviour. Among these, the most studied are oxytocin, adrenocorticotropin, α-melanocyte stimulating hormone and opioid peptides. While opioid peptides inhibit sexual performance, the others facilitate sexual behaviour in most of the species studied so far (rats, mice, monkeys and humans). However, evidence for a sexual role of gonadotropin-releasing hormone, corticotropin releasing factor, neuropeptide Y, galanin and galanin-like peptide, cholecystokinin, substance P, vasoactive intestinal peptide, vasopressin, angiotensin II, hypocretins/orexins and VGF-derived peptides are also available. Corticotropin releasing factor, neuropeptide Y, cholecystokinin, vasopressin and angiotensin II inhibit, while substance P, vasoactive intestinal peptide, hypocretins/orexins and some VGF-derived peptide facilitate sexual behaviour. Neuropeptides influence sexual behaviour by acting mainly in the hypothalamic nuclei (i.e., lateral hypothalamus, paraventricular nucleus, ventromedial nucleus, arcuate nucleus), in the medial preoptic area and in the spinal cord. However, it is often unclear whether neuropeptides influence the anticipatory phase (sexual arousal and/or motivation) or the consummatory phase (performance) of sexual behaviour, except in a few cases (e.g., opioid peptides and oxytocin). Unfortunately, scarce information has been added in the last 15 years on the neural mechanisms by which neuropeptides influence sexual behaviour, most studied neuropeptides apart. This may be due to a decreased interest of researchers on neuropeptides and sexual behaviour or on sexual behaviour in general. Such a decrease may be related to the discovery of orally effective, locally acting type V phosphodiesterase inhibitors for the therapy of erectile dysfunction.

Loss of NSCL-2 in gonadotropin releasing hormone neurons leads to reduction of pro-opiomelanocortin neurons in specific hypothalamic nuclei and causes visceral obesity.

Regulation of sexual reproduction and energy homeostasis are closely interconnected, but only few efforts were made to explore the impact of gonadotropic neurons on metabolic processes. We have used Nscl-2 mutant mice suffering from adult onset of obesity and hypogonadotropic hypogonadism to study effects of gonadotropin releasing hormone (GnRH) neurons on neuronal circuits controlling energy balance. Inactivation of Nscl-2 in GnRH neurons but not in pro-opiomelanocortin (POMC) neurons reduced POMC neurons and increased visceral fat mass, suggesting a critical role of GnRH cells in the regulation of POMC neurons. In contrast, absence of POMC processing in the majority of Nscl-2-deficient POMC neurons had no effect on energy homeostasis. Finally, we investigated the cellular basis of the reduction of GnRH neurons in NSCL-2 mutants using a lineage tracing approach. We found that loss of Nscl-2 results in aberrant migration of GnRH neurons in Nscl-2 mutant mice causing a lineage switch of ectopically located GnRH neurons.

Absent adrenarche in children with hypopituitarism: a study based on urinary steroid metabolomics.

BACKGROUND: Up to now, the regulation of adrenarche remains a myth although ACTH may possibly play an important role. METHODS: Urinary steroid profiling by gas chromatography-mass spectrometry was used to study non-invasively the adrenarchal steroid metabolome in 13 children aged 6-16 years with partial or complete hypopituitarism (HP) whose ACTH/cortisol axis was affected and compared it with 24 healthy age-matched controls. The sum of DHEA, 16α-hydroxy-DHEA and 3ß,16α,17ß-androstenetriol served as markers for adrenarche parameters (AP). The excretion rates of major urinary cortisol metabolites were also determined. RESULTS: The excretion rates for AP were significantly lower for the HP subjects than for the controls (p < 0.001). After dividing the HP group into a subgroup treated with hydrocortisone (HC) and an HC-untreated subgroup, a significant difference for AP remained for each subgroup when compared to the control group (p < 0.001 and p = 0.045, respectively). Treatment with HC had no influence on AP. CONCLUSION: The data imply indirectly a significant contribution of ACTH to the regulation of adrenarche. Our results also signify important diagnostic information: absent adrenarche can be indicative of ACTH deficiency.

Stress hormones promote growth of B16-F10 melanoma metastases: an interleukin 6- and glutathione-dependent mechanism.

BACKGROUND: Interleukin (IL)-6 (mainly of tumor origin) activates glutathione (GSH) release from hepatocytes and its interorgan transport to B16-F10 melanoma metastatic foci. We studied if this capacity to overproduce IL-6 is regulated by cancer cell-independent mechanisms. METHODS: Murine B16-F10 melanoma cells were cultured, transfected with red fluorescent protein, injected i.v. into syngenic C57BL/6J mice to generate lung and liver metastases, and isolated from metastatic foci using high-performance cell sorting. Stress hormones and IL-6 levels were measured by ELISA, and CRH expression in the brain by in situ hybridization. DNA binding activity of NF-κB, CREB, AP-1, and NF-IL-6 was measured using specific transcription factor assay kits. IL-6 expression was measured by RT-PCR, and silencing was achieved by transfection of anti-IL-6 small interfering RNA. GSH was determined by HPLC. Cell death analysis was distinguished using fluorescence microscopy, TUNEL labeling, and flow cytometry techniques. Statistical analyses were performed using Student's t test. RESULTS: Plasma levels of stress-related hormones (adrenocorticotropin hormone, corticosterone, and noradrenaline) increased, following a circadian pattern and as compared to non-tumor controls, in mice bearing B16-F10 lung or liver metastases. Corticosterone and noradrenaline, at pathophysiological levels, increased expression and secretion of IL-6 in B16-F10 cells in vitro. Corticosterone- and noradrenaline-induced transcriptional up-regulation of IL-6 gene involves changes in the DNA binding activity of nuclear factor-κB, cAMP response element-binding protein, activator protein-1, and nuclear factor for IL-6. In vivo inoculation of B16-F10 cells transfected with anti-IL-6-siRNA, treatment with a glucocorticoid receptor blocker (RU-486) or with a ß-adrenoceptor blocker (propranolol), increased hepatic GSH whereas decreased plasma IL-6 levels and metastatic growth. Corticosterone, but not NORA, also induced apoptotic cell death in metastatic cells with low GSH content. CONCLUSIONS: Our results describe an interorgan system where stress-related hormones, IL-6, and GSH coordinately regulate metastases growth.

Mechanisms regulating melanogenesis* / Mecanismos reguladores da melanogênese

Skin pigmentation is an important human phenotypic trait whose regulation, in spite of recent advances, has not yet been fully understood. The pigment melanin is produced in melanosomes by melanocytes in a complex process called melanogenesis. The melanocyte interacts with endocrine, immune, inflammatory and central nervous systems, and its activity is also regulated by extrinsic factors such as ultraviolet radiation and drugs. We have carried out a review of the current understanding of intrinsic and extrinsic factors regulating skin pigmentation, the melanogenesis stages and related gene defects. We focused on melanocyte-keratinocyte interaction, activation of melanocortin type 1 receptor (MC1-R) by peptides (melanocyte-stimulating hormone and adrenocorticotropic hormone) resulting from proopiomelanocortin (POMC) cleavage, and mechanisms of ultraviolet-induced skin pigmentation. The identification and comprehension of the melanogenesis mechanism facilitate the understanding of the pathogenesis of pigmentation disorders and the development of potential therapeutic options.

A pigmentação da pele é um importante traço fenotípico do ser humano mas apesar dos recentes avanços a sua regulação não está ainda totalmente esclarecida. O pigmento melanina é produzido nos melanossomas pelos melanócitos, num processo complexo designado por melanogénese. O melanócito interatua com os sistemas endócrino, imunitário, inflamatório e nervoso central e a sua atividade é também regulada por fatores extrínsecos como a radiação ultravioleta e fármacos. Fizemos uma revisão do conhecimento atual sobre os fatores intrínsecos e extrínsecos reguladores da pigmentação cutânea, etapas da melanogénese e defeitos genéticos relacionados. Fizemos enfoque na interação melanócito-keratinócito, na ativação do receptor da melanocortina tipo 1 (MC1-R) pelos péptidos (hormona estimuladora do melanócito e hormona adrenocorticotrófica) resultantes da clivagem da proopiomelanocortina (POMC) e mecanismos da pigmentação induzida pela radiação ultravioleta. A identificação e compreensão dos mecanismos reguladores da pigmentação cutânea facilitam o conhecimento dos mecanismos patogénicos dos distúrbios da pigmentação e o desenvolvimento de potenciais opções terapêuticas.

Impact and timing of bilateral adrenalectomy for refractory adrenocorticotropic hormone-dependent Cushing's syndrome.

INTRODUCTION: In patients with refractory adrenocorticotropic hormone-dependent Cushing's syndrome,we evaluated steroidogenesis inhibition (SI) and bilateral adrenalectomy (BA) to predict which patients might benefit most from each treatment modality. METHODS: Clinical data from patients treated 1970-2012 were reviewed retrospectively by treatment group (SI or SI+BA). Validated severity scales were used to calculate metabolic (M) score (hypokalemia, hyperglycemia, hypertension, proximal muscle weakness) and adverse events (AE) score (thrombosis, fracture, infection). RESULTS: A total of 65 patients (16 pituitary, 49 ectopic) were treated with SI+BA (n = 21,32%) or SI alone (n = 44,68%). Presenting M scores and source of adrenocorticotropic hormone excess (ectopic versus pituitary) were similar. Both groups improved metabolically after treatment. Over one-third of AEs in the SI+BA group occurred within 12 months of presentation. Half (n = 24, 55%) of the patients treated with SI died (median survival, 24.0 months). Steroid excess contributed to 71% of complications. Six SI+BA patients died (29%), including all 3 patients with recurrent Cushing's syndrome after BA. Minor perioperative complications occurred in 7 patients (33%). CONCLUSION: Posttreatment M and AE scores improved for all patients and 70% of AEs occurred in SI+BA patients within 12 months of presentation, emphasizing the importance of early operative intervention. These data argue for the safety and efficacy of early BA in selected patients with uncontrollable Cushing's syndrome.

Regulation of steroidogenesis in a primary pigmented nodular adrenocortical disease-associated adenoma leading to virilization and subclinical Cushing's syndrome.

CONTEXT: Primary pigmented nodular adrenocortical disease (PPNAD) can lead to steroid hormone overproduction. Mutations in the cAMP protein kinase A regulatory subunit type 1A (PRKAR1A) are causative of PPNAD. Steroidogenesis in PPNAD can be modified through a local glucocorticoid feed-forward loop. OBJECTIVE: Investigation of regulation of steroidogenesis in a case of PPNAD with virilization. MATERIALS AND METHODS: A 33-year-old woman presented with primary infertility due to hyperandrogenism. Elevated levels of testosterone and subclinical ACTH-independent Cushing's syndrome led to the discovery of an adrenal tumor, which was diagnosed as PPNAD. In vivo evaluation of aberrantly expressed hormone receptors showed no steroid response to known stimuli. Genetic analysis revealed a PRKAR1A protein-truncating Q28X mutation. After adrenalectomy, steroid levels normalized. Tumor cells were cultured and steroidogenic responses to ACTH and dexamethasone were measured and compared with those in normal adrenal and adrenocortical carcinoma cells. Expression levels of 17ß-hydroxysteroid dehydrogenase (17ß-HSD) types 3 and 5 and steroid receptors were quantified in PPNAD, normal adrenal, and adrenal adenoma tissues. RESULTS: Isolated PPNAD cells, analogous to normal adrenal cells, showed both increased steroidogenic enzyme expression and steroid secretion in response to ACTH. Dexamethasone did not affect steroid production in the investigated types of adrenal cells. 17ß-HSD type 5 was expressed at a higher level in the PPNAD-associated adenoma compared with control adrenal tissue. CONCLUSION: PPNAD-associated adenomas can cause virilization and infertility by adrenal androgen overproduction. This may be due to steroidogenic control mechanisms that differ from those described for PPNAD without large adenomas.