Effect Of CRH Research Articles

Involvement of CRH-R2 receptor in eating behavior and in the response of the HPT axis in rats subjected to dehydration-induced anorexia

Wistar rats subjected to dehydration-induced anorexia (DIA), with 2.5% NaCl solution as drinking water for 7 days, decrease by 80% their food intake and present some changes common to pair-fed food restricted rats (FFR) such as: weight loss, decreased serum leptin and expression of orexigenic arcuate peptides, increasing the anorexigenic ones and serum corticosterone levels. In contrast, the response of the HPT axis differs: DIA animals have increased TRH expression in PVN and present primary as opposed to the tertiary hypothyroidism of the FFR. Exclusive to DIA is the activation of CRHergic neurons in the lateral hypothalamus (LH) that project to PVN. Since TRH neurons of the PVN contain CRH receptors, we hypothesized that the differences in the response of the HPT axis to DIA could be due to CRH regulating TRHergic neurons. CRH effect was first evaluated on TRH expression of cultured hypothalamic cells where TRH mRNA levels increased after 1h with 0.1nM of CRH. We then measured the mRNA levels of CRH receptors in the PVN of male and female rats subjected to DIA; only those of CRH-R2 were modulated (down-regulated). The CRH-R2 antagonist antisauvagine-30 was therefore injected into the PVN of male rats, during the 7 days of DIA. Antisauvagine-30 induced a higher food intake than controls, and impeded the changes produced by DIA on the HPT axis: PVN TRH mRNA, and serum TH and TSH levels were decreased to similar values of FFR animals. Results corroborate the anorexigenic effect of CRH and show its role, acting through CRH-R2 receptors, in the activation of TRHergic PVN neurons caused by DIA. These new data further supports clinical trials with CRH-R2 antagonists in anorexia nervosa patients.

Central and peripheral integration of interrenal and thyroid axes signals in common carp (Cyprinus carpio L.)

In teleostean fishes the hypothalamic-pituitary-thyroid axis (HPT axis) and the hypothalamic-pituitary-interrenal axis (HPI axis) regulate the release of thyroid hormones (THs) and cortisol respectively. Since many actions of both hormones are involved in the regulation of metabolic processes, communication between both signal pathways can be anticipated. In this study, we describe central and peripheral sites for direct interaction between mediators of both neuroendocrine axes in the common carp (Cyprinus carpio). Despite suggestions in the literature that CRH is thyrotropic in some fish; we were not able to establish stimulatory effects of CRH on the expression of the pituitary TSHbeta subunit gene. In preoptic area tissue incubated with 10(-7) M thyroxine (T(4)) a 2 x 9-fold increase in the expression of CRH-binding protein (CRHBP) was observed. Thus, T(4) could reduce the bioavailable hypothalamic crh via the up regulation of crhbp expression and hence down regulate the HPI axis. At the peripheral level, cortisol (10(-6) M), ACTH (10(-7) M), and alpha-MSH (10(-7) M) stimulate the release of T(4) from kidney and head kidney fragments, which contain all functional thyroid follicles in carp, by two- to fourfold. The substantiation of three pituitary thyrotropic factors, viz. TSH, ACTH, and alpha-MSH, in common carp, allows for an integration of central thyrotropic signals. Clearly, two sites for interaction between the HPT axis, the HPI axis, and alpha-MSH are present in common carp. These interactions may be key to the proper regulation of general metabolism in this fish.

Corticotropin releasing hormone (CRH), melanocortins (MC) and thyrotropin releasing hormone (TRH) stimulate pigmentation and melanocyte function in the human hair follicle

Melanocortins (MC) such as adrenocorticotropic hormon (ACTH) and α‐melanocyte‐stimulating hormone (αMSH) are neuropeptides derived from the prohormone proopiomelanocortin (POMC). It is now well established that the human skin is not only a target but also a local source for MCs. Almost all cutaneous cell types express MCs and MC‐receptor (MCRs) in vitro. The POMC peptides, their receptors and CRH the main inducer of POMC gene/protein expression in the pituitary and in skin ‐were also detected in human scalp hair follicles (HFs). MCs regulate pigmentation: stimulate melanogenesis, dendricity and proliferation in epidermal melanocytes, and similar effect was reported recently on cultured melanocytes derived from the outer root sheath of human HFs. TRH is the most proximal member of the hypothalamic‐pituitary‐thyroid (HPT) axis. In amphibian skin, TRH also regulates POMC release, which leads to skin darkening via αMSH‐MC1R interactions. Recently we found TRH and TRH‐R expression in human HFs. Therefore, we examined the – as yet ill‐explored – effect of exogenous CRH, ACTH, αMSH and TRH on melanin production, melanocytes number and dendricity in normal, microdissected, organ‐cultured human anagen scalp HFs. Melanin production was measured by quantitaive Masson‐Fontana histochemistry, and melanocyte dendricity were assessed by immunohistochemistry against the melanosome marker gp100 (Nki‐beteb). The melanin content increased significantly after αMSH (10–100 nM) and TRH(1–10 ng/ml) addition to the medium. Total Nki‐beteb immunoreactivity was significantly elevated in the HF melanocytes treated with αMSH, thus confirming the Masson‐Fontana results. TRH, CRH (10 nM–100 pM) and MC (10–100 nM) also stimulated dendrite formation of HF pigmentary unit melanocytes. CRH, MCs and TRH as well were able to compensate the significant decline of the melanin content caused by catagen induction with TGFβ2. This provides unequivocal evidence that CRH, ACTH and a‐MSH stimulate normal human hair follicle pigmentation in situ. We also show for first time that TRH, a key regulator of pigmentation in amphibian skin, might play similar role in human HF.

COERULEAR ACTIVATION BY CRH AND ITS ROLE IN HYPERTENSION INDUCED BY PRENATAL MALNUTRITION IN THE RAT

The effects of intracoerulear CRH and intraparaventricular prazosin on systolic pressure, diastolic pressure and heart rate were studied in prenatally malnourished hypertensive rats. At day 40 of life, (i) malnourished rats showed enhanced systolic pressure, heart rate, and plasma corticosterone; (ii) intracoerulear CRH increased systolic pressure and heart rate only in controls; (iii) intraparaventricular prazosin decreased systolic pressure and heart rate only in malnourished rats; (iv) in controls, prazosin did not prevent the stimulatory effect of CRH on the cardiovascular parameters; in malnourished rats, prazosin allowed CRH regain its stimulatory effects. Thus, coerulear activation by CRH would be involved in hypertension and tachycardia developed by prenatally malnourished animals.

CRH functions as a growth factor/cytokine in the skin.

We tested the effect of CRH and related peptides in a large panel of human skin cells for growth factor/cytokine activities. In skin cells CRH action is mediated by CRH-R1, a subject to posttranslational modification with expression of alternatively spliced isoforms. Activation of CRH-R1 induced generation of both cAMP and IP3 in the majority of epidermal and dermal cells (except for normal keratinocytes and one melanoma line), indicating cell type-dependent coupling to signal transduction pathways. Phenotypic effects on cell proliferation were however dependent on both cell type and nutrition conditions. Specifically, CRH stimulated dermal fibroblasts proliferation, by increasing transition from G1/0 to the S phase, while in keratinocytes CRH inhibited cell proliferation. In normal and immortalized melanocytes CRH effect showed dichotomy and thus, it inhibited melanocyte proliferation in serum-containing medium CRH through G2 arrest, while serum free media led instead to CRH enhanced DNA synthesis (through increased transition from G1/G0 to S phase and decreased subG1 signal, indicating DNA degradation). CRH also induced inhibition of early and late apoptosis in the same cells, demonstrated by analysis with the annexin V stains. Thus, CRH acts on epidermal melanocytes as a survival factor under the stress of starvation (anti-apoptotic) as well as inhibitor of growth factors induced cell proliferation. In conclusion, CRH and related peptides can couple CRH-R1 to any of diverse signal transduction pathways; they also regulate cell viability and proliferation in cell type and growth condition-dependent manners.

Corticotropin-Releasing Hormone Directly Stimulates Thermogenesis in Skeletal Muscle Possibly through Substrate Cycling between de Novo Lipogenesis and Lipid Oxidation

The mechanisms by which CRH and related peptides (i.e. the CRH/urocortin system) exert their control over thermogenesis and weight regulation have until now focused only upon their effects on brain centers controlling sympathetic outflow. Using a method that involves repeated oxygen uptake determinations in intact mouse skeletal muscle, we report here that CRH can act directly on skeletal muscle to stimulate thermogenesis, an effect that is more pronounced in oxidative than in glycolytic muscles and that can be inhibited by a selective CRH-R2 antagonist or blunted by a nonselective CRH receptor antagonist. This thermogenic effect of CRH can also be blocked by interference along pathways of de novo lipogenesis and lipid oxidation, as well as by inhibitors of phosphatidylinositol 3-kinase or AMP-activated protein kinase. Taken together, these studies demonstrate that CRH can directly stimulate thermogenesis in skeletal muscle, and in addition raise the possibility that this thermogenic effect, which requires both phosphatidylinositol 3-kinase and AMP-activated protein kinase signaling, might occur via substrate cycling between de novo lipogenesis and lipid oxidation. The effect of CRH in directly stimulating thermogenesis in skeletal muscle underscores a potentially important peripheral role for the CRH/urocortin system in the control of thermogenesis in this tissue, in its protection against excessive intramyocellular lipid storage, and hence against skeletal muscle lipotoxicity and insulin resistance.

Corticotropin-Releasing Hormone and Urocortin Induce Secretion of Matrix Metalloproteinase-9 (MMP-9) without Change in Tissue Inhibitors of MMP-1 by Cultured Cells from Human Placenta and Fetal Membranes

Matrix metalloproteinases (MMPs) are essential for human parturition due to their degrading of the extracellular matrix. CRH and urocortin (Ucn) are thought to play a central role in the mechanisms controlling human pregnancy and parturition. The aim of this study was to assess the effects of CRH and Ucn on MMP-9 and tissue inhibitors of MMP-1 (TIMP-1) protein and/or mRNA levels in vitro. Zymography, Western blotting, real-time RT-PCR, and culture/treatments of purified sycytiotrophoblast, chorion trophoblast, and amniotic epithelial cells from human placenta and fetal membranes were performed. CRH and Ucn significantly increased MMP-9 protein secretion from cultured chorionic trophoblast, amnion epithelial, and syncytiotrophoblast cells (P < 0.01, compared with control, respectively), but there was no effect on TIMP-1 secretion and MMP-9 mRNA expression. Antalarmin (a CRH receptor type 1 antagonist) significantly blocked CRH- and Ucn-induced pro-MMP-9 secretion from three cell types (P < 0.01, compared with treatment with CRH and Ucn alone, respectively). Antisauvagine 30 (a CRH receptor type 2 antagonist) resulted in a significant reduction in CRH- and Ucn-induced secretion from chorionic trophoblast cells (P < 0.05) and syncytiotrophoblast cells (P < 0.01) compared with treatment with CRH and Ucn alone, respectively, but had no significant effect on amniotic epithelial cells. Our results suggest that CRH and Ucn may play a role in the mechanisms controlling human parturition and preterm delivery not only by affecting myometrial contractility, but also by increasing local MMP activity in placenta and fetal membranes, thereby contributing to membrane rupture with the onset and progression of human labor.

Alpha-Helical CRH Exerts CRH Agonistic Effects on Sleep-Endocrine Activity in Humans

CRH is known to enhance wakefulness and to reduce SWS. In addition, some but not all, studies suggest that CRH promotes REM sleep. Alpha-helical CRH exerts CRH-antagonistic effects in various studies. We studied its effect on sleep EEG and nocturnal secretion of ACTH, cortisol, GH (n = 7) in young normal male subjects. After administering the substance cortisol and ACTH levels were enhanced during the total night compared to placebo. We found an increase of the time spent awake for the first half. ACTH (2nd half of the night) and cortisol (total night and 1st half of the night) increased. The results of the present study correspond to a mixture of agonistic and antagonistic effects of alpha-helical CRH.

Regulation of progesterone production in human term trophoblasts in vitro by CRH, ACTH and cortisol (prednisolone)

In most mammals, onset of labor is accompanied with progesterone withdrawal. In humans, cortisol blockade of progesterone is a possible mechanism involved in the initiation of labor. Therefore, aim of the study was to clarify the effect of CRH, ACTH and cortisol (prednisolone) on the release of progesterone by term trophoblast cells in vitro. Cytotrophoblast cells were prepared from human term placentas by standard dispersion of villous tissue followed by a percoll gradient centrifugation step. Trophoblasts were incubated with CRH, ACTH as well as with prednisolone. The release of progesterone is decreased in CRH- and ACTH-treated trophoblast cell cultures compared to untreated trophoblast cells. Addition of prednisolone in varying concentrations leads to an increase of trophoblast progesterone production. The results suggest that CRH and ACTH directly modulate the endocrine function of trophoblasts in culture by downregulating progesterone production. Prednisolone on the other hand showed a stimulating effect on progesterone production in term trophoblast cells in vitro. Because blockade of progesterone is a possible mechanism involved in initiation of labor, we may speculate that CRH and ACTH are directly involved in the auto- or paracrine regulation of this procedure.

Effect of ACTH and CRH on Plasma Levels of Cortisol and Prostaglandin F2α Metabolite in Cycling Gilts and Castrated Boars

The present study was designed to evaluate the effects of synthetic ACTH (1–24, tetracosactid) and porcine CRH on the plasma levels of cortisol and PGF2α metabolite in cycling gilts (n = 3) and castrated boars (n = 3). The experiments were designed as crossover studies for each gender separately. Each animal received, during three consecutive days; 1) ACTH (Synacthen® Depot) at a dose of 10 μg/kg body weight in 5 ml physiological saline, 2) porcine CRH at a dose 0.6 μg/kg body weight in 5 ml physiological saline or 3) physiological saline (5 ml). The test substances were administered via an indwelling jugular cannula in randomized order according to a Latin square. The administration of ACTH to cycling gilts resulted in concomitant elevations of cortisol and PGF2α metabolite with peak levels reached at 70.0 ± 10.0 and 33.3 ± 6.7 min, respectively. Similarly, the administration of ACTH to castrated boars resulted in concomitant elevation of cortisol and PGF2α metabolite with peak levels reached at 60.0 ± 0.0 and 20.0 ± 0.0 min, respectively. Cortisol peaked at 20 min after administration of CRH in both cycling gilts and castrated boars with maximum levels of 149.3 ± 16.5 nmol/1 and 138.3 ± 10.1 nmol/1, respectively. It can be concluded that administration of synthetic ACTH (tetracosactid) to pigs caused a concomitant elevation of cortisol and PGF2α metabolite levels in both cycling gilts as well as castrated boars. The administration of CRH to pigs resulted in an elevation of cortisol levels in both cycling gilts and castrated boars. Conversely, PGF2α metabolite levels were not influenced by the administration of CRH either in cycling gilts or in castrated boars.

Corticotropin-Releasing Hormone-Mediated Induction of Intracellular Signaling Pathways and Brain-Derived Neurotrophic Factor Expression Is Inhibited by the Activation of the Endocannabinoid System

CRH receptor (CRHR) 1 and the cannabinoid receptor 1 (CB1) are both G protein-coupled receptors. Activation of CRHR1 leads to increases in cAMP production and phosphorylation of the transcription factor cAMP response element-binding protein (CREB). In contrast, CB1 is negatively coupled to the cAMP signaling cascade. In this study, we analyzed a putative interaction between these two systems focusing on the regulation of the expression of brain-derived neurotrophic factor (BDNF), a CREB-regulated gene. In situ hybridization revealed coexpression of CRHR1 and CB1 receptors in the granular layer of the cerebellum. Therefore, we analyzed the effects of CRH and the CB1 agonist WIN-55,212-2 on BDNF expression in primary cerebellar neurons from rats and mice. We observed that application of CRH for 48 h led to an increase in BDNF mRNA and protein levels. This effect was inhibited by WIN-55,212-2. At the level of intracellular signaling, short-term application of WIN-55,212-2 inhibited CRH-induced cAMP accumulation and CREB phosphorylation. Pharmacological analysis demonstrated that the CRHR1 antagonist R121919, the protein kinase A inhibitor H89, and the calcium chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester inhibited CRH-mediated BDNF expression. Moreover, depolarization-induced BDNF synthesis was also inhibited by long-term application of WIN-55,212-2 in wild-type mice but not in CB1-deficient mice. Thus, these data highlight an interaction between the CRH and the cannabinoid system in the regulation of BDNF expression by influencing cAMP and Ca2+ signaling pathways.

Sonic hedgehog regulates CRH signal transduction in the adult pituitary

Sonic hedgehog (Shh) is a signaling protein that binds to Patched and mediates its effects through Gli transcription factors. Shh is important in regulating survival and growth in both the embryo and the adult. It is known to be involved in pituitary development, but its role in the adult pituitary has not been investigated. Here, we show Shh and Gli1 immunoreactivity in adult human corticotroph cells. Administration of Shh (5 microg/ml) alone and in combination with corticotrophin-releasing hormone (CRH; 100 nM) in dispersed rat anterior pituitary and AtT-20 mouse corticotrophinoma cells increased corticotrophin (ACTH) secretion and pro-opiomelanocortin (POMC) promoter activity. Shh and CRH act additively in increasing CRH receptor 1 (CRH-R1). Unexpectedly, we found that CRH on its own increased Gli-dependent transcription, which in turn stimulated POMC transcription. Gli1 is necessary for CRH signaling, since knocking down Gli1 by RNA interference abolished the stimulatory effect of CRH on POMC. Taken together, our results demonstrate a new role for Shh and Gli1 in corticotroph function and provide a new link between Shh and CRH signaling pathways.

Macrophage migration inhibitory factor is released from pituitary folliculo-stellate-like cells by endotoxin and dexamethasone and attenuates the steroid-induced inhibition of interleukin 6 release.

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine produced by peripheral immune cells and also by endocrine cells in the anterior pituitary gland. MIF exerts its proinflammatory actions in the host-defense system by blocking the inhibitory effects of glucocorticoids on the release of other proinflammatory cytokines (e.g. IL-1, IL-6, TNFalpha). Reports that pituitary folliculo-stellate (FS) cells share many characteristics with immune cells led us to propose that these cells may serve as an additional source of MIF in the pituitary and that pituitary-derived MIF may act in an autocrine or paracrine manner to modulate endotoxin-induced cytokine release from FS cells. In the present study we addressed this hypothesis by using 1) immunohistochemistry to localize MIF in primary pituitary tissue and 2) well-characterized FS (TtT/GF), corticotroph (AtT20), and macrophage/monocyte (RAW 264.7) cell lines to explore the effects of CRH, endotoxin, and dexamethasone on MIF release and to examine the effects of MIF on IL-6 release. Our immunohistochemical study showed that MIF is expressed in abundance in S100-positive FS cells and also in other pituitary cell types. All three cell lines expressed MIF protein and responded to endotoxin (10-1000 ng/ml, 24 h) and dexamethasone (100 pM to 10 nM, 24 h) with concentration-dependent increases in MIF release. CRH (10-100 nM) also stimulated MIF release from AtT20 cells but, unlike endotoxin and dexamethasone, it had no effect on MIF release from TtT/GF or RAW cells. Recombinant MIF did not affect the basal release of IL-6 from TtT/GF cells; however, it effectively reversed the inhibitory effects of dexamethasone (1 nM) on the endotoxin-induced release of IL-6 from these cells. The results suggest that the FS cells are both a source of and a target for MIF and raise the possibility that MIF serves as a paracrine/autocrine factor in the pituitary gland that contributes to the protective neuroendocrine response to endotoxin.

Corticotropin-releasing hormone system in human adipose tissue.

Mounting evidence exists for a role of the CRH system in energy balance, including a direct influence on human adipocytes, the regulation of adipose 11 beta-hydroxysteroid dehydrogenase type 1 activity, and cortisol formation. We characterized the expression of CRH receptors 1 and 2 and CRH-like peptides stresscopin and urocortin in human adipose tissue in comparison with other peripheral tissues, adrenal, and heart. The effect of CRH on CRH receptor and CRH-like peptide expression was analyzed in isolated human adipocytes using quantitative TaqMan PCR. CRH receptors were detectable in fat tissue at mRNA and protein levels. CRH-R2 expression in fat was comparable with its expression in the heart, the organ with the highest CRH-R2 expression known. CRH-R1:CRH-R2 ratio varied according to fat-depot type; whereas CRH-R1 expression was higher in sc fat than in visceral fat, the opposite was true for CRH-R2. Adipose tissue also expressed urocortin and stresscopin, the predominant ligands of peripheral CRH-R2. CRH down-regulated CRH-R1 and CRH-R2 mRNA expression in isolated adipocytes. These data, together with the recently published observation that CRH regulates adipocyte metabolism by down-regulating 11 beta-hydroxysteroid dehydrogenase, indicate that a CRH system exists within human adipose tissue. This system could be implicated in energy homeostasis and in mediating the anorexic effects of CRH at adipose level.

Synergistic effects of sonic hedgehog and CRH on ACTH secretion

Synergistic effects of sonic hedgehog and CRH on ACTH secretion

Possible regulatory mechanism of DHA-induced anti-stress reaction in rats

To determine whether docosahexaenoic acid (DHA) affects stress responses in rats, we investigated its influence on several behavioral tests. Female rats were fed a diet deficient in (n-3) fatty acid from mating through pregnancy and lactation. Male pups fed the same diet as their dams were used for experiments. The effects of dietary (n-3) fatty acid deficiency and supplementation with DHA on psychological stress and conditioned-fear stress were investigated. The effect of DHA on psychological stress was examined by an elevated plus-maze test. The (n-3) deficient rats spent significantly ( P<0.05) less time in the open arms; after 1 week of supplementation with DHA, they showed a significant ( P<0.01) improvement. We then examined the paired effects of DHA and CRH on stress manifestations by an intracerebroventricular (i.c.v.) cannulation and behavior testing. An i.c.v. infusion of CRH (500 pmol) under resting conditions was shown to have stress-inducing effects on behavior such as decreases of rearing, smelling and feeding, and increases of face washing; the supplementation of DHA significantly improved these distress behaviors. Finally, conditioned fear was induced by 40 min forced exposure to a cage in which the rat had experienced footshocks (30×1 mA×1 s) 1 day before. Freezing behavior was dramatically suppressed by the supplementation of DHA, even 48 h after the conditioning treatment. Furthermore, the effect of DHA on the conditioned fear stress response is maintained over a long-term period. The i.c.v. pre-treatment of rats with bicuculline, a GABA A receptor antagonist, enhanced the conditioned-fear-induced freezing time in a dose-dependent fashion in the (n-3) fatty acid deficient animals. Significantly, the DHA supplemented group was not affected by the pre-treatment with bicuculline. From these findings, it is concluded that the involvement of DHA in stress responses may act via a GABA A receptor-mediated mechanism.

Regulation of Nuclear Factor-κB by Corticotropin-Releasing Hormone in Mouse Thymocytes

CRH, a major mediator of the stress response, has been shown to exert potent immunomodulatory effects in vivo, through mechanisms that have not been elucidated yet. To determine the molecular pathways mediating the proinflammatory effects of peripheral CRH, we studied its role in the activation of nuclear factor-kappaB (NF-kappaB), a transcription factor crucial for the regulation of a variety of inflammatory mediator genes. Our studies demonstrate that, in mouse thymocytes, CRH induces the NF-kappaB DNA-binding activity in a time- and dose-dependent manner, with parallel degradation of its inhibitor protein inhibitor of NF-kappaB. The effect of CRH is not inhibited by dexamethasone and is mediated by the protein kinase A and protein kinase C signaling pathways. In vivo, we show that CRH-deficient mice respond to lipopolysaccharide administration by reduced activation of thymus NF-kappaB, despite their significantly elevated proinflammatory cytokine and their low corticosterone levels. These findings suggest a putative molecular pathway mediating the proinflammatory effects of peripheral CRH through induction of the NF-kappaB DNA binding activity.

Corticotropin-releasing hormone augments proinflammatory cytokine production from macrophages in vitro and in lipopolysaccharide-induced endotoxin shock in mice.

Corticotropin-releasing hormone (CRH) exerts an anti-inflammatory effect indirectly, via cortisole production, and a proinflammatory effect directly on immune cells. The aim of the present work was to examine the effect of CRH on macrophage-derived cytokines both in vitro and in vivo. For the in vitro experiments we used two types of macrophages: (i) the RAW264.7 monocyte/macrophage cell line and (ii) thioglycolate-elicited peritoneal macrophages from BALB/c mice. We have found that CRH enhanced lipopolysaccharide (LPS)-induced tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), and IL-6 production. For the in vivo experiments we have used the LPS-induced endotoxin shock model in BALB/c mice, an established model for systemic inflammation in which macrophages are the major source of the proinflammatory cytokines responsible for the development of the shock. Administration of antalarmin, a synthetic CRH receptor 1 (CRHR1) antagonist, prior to LPS prolonged survival in a statistically significant manner. The effect was more evident at the early stages of endotoxin shock. CRHR1 blockade suppressed LPS-induced elevation of the macrophage-derived cytokines TNF-alpha, IL-1beta, and IL-6, confirming the role of CRH signals in cytokine expression. In conclusion, our data suggest that CRH signals play an early and crucial role in augmenting LPS-induced proinflammatory cytokine production by macrophages. Our data suggest that the diffuse neuroendocrine system via CRH directly affects the immune system at the level of macrophage activation and cytokine production.

Mechanics of missile penetration into geo-materials

The present study aims to improve an existing model for the prediction of deceleration time history, penetration depth and forces on ogive and conical nose shaped missiles under normal impact into geo-material targets. The actual ogive nose shaped missile has been considered in the analysis and the results thus obtained have been compared with the existing model and significant improvements are found. A close proximity in the results has also been observed with the experimental values. The results of ogive nose shaped missile have also been compared with equivalent conical nose shaped missile. Variation of radial stresses along nose length and radial direction has been studied. Effect of CRH on missile penetrating performance has been investigated.

CRH inhibits cell growth of human endometrial adenocarcinoma cells via CRH-receptor 1-mediated activation of cAMP-PKA pathway.

CRH produced by human endometrial cells exerts decidualizing activity via an autocrine mechanism mediated via CRH-R1 receptors. We postulated that such activity exerted by CRH on normal endometrial cells might translate into an antiproliferative action on endometrial-derived malignancies, provided that neoplastic cells maintain the expression of CRH receptors. In this light, here we investigated the possible antiproliferative effects of CRH in an adenocarcinoma cell line derived from human endometrium. CRH induces time- and concentration-dependent inhibition of Ishikawa cell growth, the maximal effect (50% inhibition) being achieved after 3 d of treatment with 10(-7) M CRH. A decrease in telomerase activity, which paralleled tumor growth inhibition, was also observed in CRH-treated samples. The antiproliferative effect was confirmed by colony-formation assay for long-term survival. This effect was counteracted in a concentration-dependent manner by both alpha-helical CRH and astressin; the former also showed intrinsic inhibitory activity. These findings suggested the involvement of CRH-R1 receptor subtype; this hypothesis was confirmed by RNase protection analysis showing the expression of human CRH-R1 mRNA. Experiments with the PKA inhibitor 14-22 amide and forskolin, as well as the measurement of intracellular cAMP, suggested the downstream involvement of cAMP-PKA pathway in CRH-induced inhibition of Ishikawa cell growth.