Glucocorticoid receptor signaling in the brain and its involvement in cognitive function

The hypothalamic-pituitary-adrenal axis regulates the secretion of glucoco rticoids in response to environmental challenges.In the brain,a nuclear receptor transcription fa ctor,the glucocorticoid recepto r,is an important component of the hypothalamicpituitary-a d renal axis's negative feedback loop and plays a key role in regulating cognitive equilibrium and neuroplasticity.The glucoco rticoid receptor influences cognitive processes,including glutamate neurotransmission,calcium signaling,and the activation of brain-derived neurotrophic factor-mediated pathways,through a combination of genomic and non-genomic mechanisms.Protein interactions within the central nervous system can alter the expression and activity of the glucocorticoid receptor,there by affecting the hypothalamic-pituitary-a d renal axis and stress-related cognitive functions.An appropriate level of glucocorticoid receptor expression can improve cognitive function,while excessive glucocorticoid receptors or long-term exposure to glucoco rticoids may lead to cognitive impairment.Patients with cognitive impairment-associated diseases,such as Alzheimer's disease,aging,depression,Parkinson's disease,Huntington's disease,stroke,and addiction,often present with dysregulation of the hypothalamic-pituitary-adrenal axis and glucocorticoid receptor expression.This review provides a comprehensive overview of the functions of the glucoco rticoid receptor in the hypothalamic-pituitary-a d renal axis and cognitive activities.It emphasizes that appropriate glucocorticoid receptor signaling fa cilitates learning and memory,while its dysregulation can lead to cognitive impairment.This provides clues about how glucocorticoid receptor signaling can be targeted to ove rcome cognitive disability-related disorders.

Efficacy and anti-inflammatory analysis of glucocorticoid,antihistamine and leukotriene receptor antagonist in the treatment of allergic rhinitis

BACKGROUND There are many adverse reactions in the treatment of allergic rhinitis(AR)mainly with conventional drugs.Leukotriene receptor antagonists,glucocorticoids and nasal antihistamines can all be used as first-line drugs for AR,but the clinical effects of the three drugs are not clear.AIM To examine the impact of glucocorticoids,antihistamines,and leukotriene receptor antagonists on individuals diagnosed with AR,specifically focusing on their influence on serum inflammatory indexes.METHODS The present retrospective study focused on the clinical data of 80 patients diagnosed and treated for AR at our hospital between May 2019 and May 2021.The participants were categorized into the control group and the observation group.The control group received leukotriene receptor antagonists,while the observation group was administered glucocorticoids and antihistamines.Conducted an observation and comparison of the symptoms,physical sign scores,adverse reactions,and effects on serum inflammatory indexes in two distinct groups of patients,both before and after treatment.RESULTS Subsequent to treatment,the nasal itching score,sneeze score,runny nose score,nasal congestion score,and physical signs score exhibited notable discrepancies(P<0.05),with the observation group demonstrating superior outcomes compared to the control group(P<0.05).The interleukin(IL)-6,IL-10,tumor necrosis factor-alpha,Soluble Intercellular Adhesion Molecule-1,Leukotriene D4 after treatment were significantly different and the observation group It is better than the control group,which is statistically significant(P<0.05).Following the intervention,the incidence of adverse reactions in the observation group,including symptoms such as nasal dryness,discomfort in the throat,bitter taste in the mouth,and minor erosion of the nasal mucosa,was found to be 7.5%.This rate was significantly lower compared to the control group,which reported an incidence of 27.5%.The difference between the two groups was statistically significant(P<0.05).CONCLUSION Glucocorticoids and antihistamines have obvious therapeutic effects,reduce serum inflammatory index levels,relieve symptoms and signs of patients,and promote patients'recovery,which can provide a reference for clinical treatment of AR.

Rapamycin Sensitizes Glucocorticoid Resistant Acute Lymphoblastic Leukemia CEM-C1 Cells to Dexamethasone Induced Apoptosis through both mTOR Suppression and Up-Regulation and Activation of Glucocorticoid Receptor

Objective To explore the role of glucocorticoid （GC） receptor （GR） in rapamycin＇s reversion of GC resistance in humanGC-resistant T-acute lymphoblastic leukemia （ALL） CEM-C1 cells. Methods CEM-C1 cells were cultured in vitro and treated with rapamycin at different concentrations with or without 1 μmol/L dexamethasone （Dex）. 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide （MTT） test was performed to assess cell proliferation. The cell cycle and cell apoptosis were analyzed by flow cytometry. The expression of GRα mRNA was determined by real-time quantitative RT-PCR. The expression of GR, p-70S6K, Mcl-1, and Bim proteins was detected by Western blot. Results When incubated with rapamycin at different concentrations, CEM-C1 cells showed significant growth inhibition in a time- and concentration-dependent manner. The growth inhibition was synergistically increased when CEM-C1 cells were treated with rapamycin plus 1 μmol/L Dex. CEM-C1 cells treated with rapamycin alone showed no apparent apoptosis, and were arrested at G0/G1 phase. After the treatment with Dex plus rapamycin, CEM-C1 cells demonstrated apparent apoptosis and increased the cell cycle arrested at G0/G1 phase. Rapamycin combined with Dex up-regulated GRα, phosphorylated GR（p-GR）, and pro-apoptotic protein Bim-EL in CEM-C1 cells, but inhibited the expression of p-p70S6K, a downstream target protein ofmTOR （mammalian target of rapamycin）. Conclusion After the treatment with rapamycin plus Dex, Dex resistant CEM-C1 cells induce growth inhibition and apoptosis. The underlying mechanism may involve inhibition of the mTOR signaling pathway and also be associated with up-regulation of GR expression and activation of GC-GR signaling pathway.

Effects of glucocorticoids on the growth and chemosensitivity of carcinoma cells are heterogeneous and require high concentration of functional glucocorticoid receptors

AIM： To determine how glucocorticoids （GCs） may affect the growth and chemosensitivity of common carcinoma cells. METHODS： The effect of dexamethasone （DEX） on growth and chemosensitivity was assessed in 14 carcinoma cell lines. The function of GC receptors （GR） was assessed by MMTV reporter assay. Overexpression of GR was done by in vitro transfection and expression of a GR-expressing vector. Immunohistochemical stain of tissues and ceils were done by PA1-511A, an anti-GR monodonal antibody. RESULTS： DEX inhibited cell growth of four （MCF-7, MCF- 7/MXR1, MCF-7/TPT300, and HeLa）, increased cisplatin cytoxicity of one （SiHa）, and decreased dsplatin cytotoxicity of two （H460 and Hep3B） cell lines. The GR content of the seven cell lines affected by DEX was significantly higher than those of the seven cell lines unaffected by DEX （5.2±2.5×10^4 sites/cell vs1.3±1.4×10^4 sites/cell, P= 0.005）. Only two DEX-unresponsive cell lines {NPC-TW01 and NPC- TW04） oontained high GR amounts in the range （1.9-8.1×10^4 sites/cell） of the seven DEX-responsive cell lines. The GR function of NPC-TW01 and NPC-TW04, however, was foundto be impaired. The importance of high cellular amount of GR in mediating DEX susceptibility of the cells was further exemplified by GR dose-dependent drug resistance to cisplatin of AGS, a cell line with low GR content and was unaffected by DEX before transfection of GR-expressing vector. Immunohistochemical studies of human cancer tissues showed that 5 of the 45 （11.1%） breast cancer and 43 of the 85 （50.6%） non-small cell lung cancer had high GR contents at the ranges of the GC-responsive carcinoma cell lines. CONCLUSION： The growth and chemosensitivity of human carcinomas with high GR contents may be affected by GC. However, in light of the heterogeneous and even contradictive effects of GC on these cells, routine examination of GR contents of human carcinoma tissues may not be clinically useful until other markers that help predict the ultimate effect of GC on individual patients are identified.

Studies on the homogeneity between high-and lowaffinity glucocorticoid receptor

The homogeneity between the high-and low-affinity glucocorticoid receptors(GR_H and GR_L)was testified by immunoaffinity chromatography using Mab N250(recognizing the immunogenic domain at the N terminal of GR_H)and Mab BuGR1(recognizing the DNA binding domain of GR_H).The specific binding peak of 0.98μmol/L[~3H]triamcinolone acetonide(TA)was higher than that of 52.50nmol/L[~3H]TA.The re-sult suggests that the antigenic determinants of GR_L are similar to those of GR_H.ThecDNA of rat liver GR_H was introduced into GR_H-and GR_L-negative mouse fibroblast cellline E82.A3 by calcium phosphate coprecipitation.A number of clones which expressGR_H were selected with G418(400μg/ml).The results of radioligand binding assay indicatethat GR_H gene is expressed successfully and GR_L also may be encoded by GR_H gene.

Effect of Dexamethasone on Expression of Glucocorticoid Receptor in Human Monocyte Cell Line THP-1

The effect of dexamethasone with different concentrations and different stimulating periods on the expression of glucocorticoid receptors （GRα, GRβ） protein was investigated in human monocyte cell line THP-1. The cultured human monocyte line THP-1 cells were stimulated by dexamethasone with different concentrations and different periods. The expression of GRα and GRβ protein was detected by Western hlotting. The results showed that the expression of GRα and GRβ was detected in the THP-1 cells, The quantity of GRα expression was reduced by dexamethasone under the same concentration with the prolongation of expression was increased by dexamethasone treatment the stimulating periods. The quantity of GRβ in a time- and dose-dependent manner. It was concluded that dexamethasone stimulation time-dependently reduced the GRα expression in THP-1 cells. Dexamethasone stimulation time- and dose-dependently increased the GRβ expression in THP- 1 cells. The expression of GRα and GRβas regulated by glucocorticoid.

Escin enhances anti-rheumatoid arthritis effects of low dose glucocorticoids through up-regulation of glucocorticoid receptor

OBJECTIVE To investigate the anti-rheumatoid arthritis(RA)effect of Escin combined with low dose of GCs(dexameth⁃asone,Dex)and its underlying mechanism.METHODS Adjuvant-induced rheumatoid arthritis rats and LPS-injured RAW 264.7 were used to investigate the anti-RA effects of Escin combined with low dose Dex in vivo and in vitro.In vivo experiment:rats were randomly divided into model group(AIA),dexamethasone high dose(Dex,0.2 mg·kg^-1)group,dexamethasone low dose(Dex,0.05 mg·kg^-1)group,Escin 10 mg·kg^-1 group,Dex 0.05+Escin group,10 rats in each group,another 10 were used as normal control group.The vehicle and the corresponding drug were administered intragastrically(ig)daily for 14 d.In vitro experiment:LPS was used to stimulate RAW 264.7 macrophages for inflammatory models,which were divided into control group,LPS group,Dex with high dose(50 nmol·L^-1)group,and Dex with low dose(12.5 nmol·L^-1)group.In the Escin 10μmol·L^-1 group and the Dex+Escin(12.5 nmol·L^-1+10μmol·L^-1)group,the corresponding drugs were added to each well.After 2 h,LPS was added to induce inflammation.RESULTS Escin combined with low dose Dex significantly decreased arthritic index,serum IL-6 and TNF-α,improved paw swelling,and ameliorated the joint pathology immune organ pathology significantly.Gene chip results revealed that Nr3c1(GR)altered significantly.And that GR activation by Escin and low dose Dex was confirmed both in vivo and in vitro.Furthermore,Escin combined with low dose Dex also significant increase GR mRNA expression.However,when suppression of GR by its specific inhibitor,the anti-RA effect of Escin combined with low dose Dex was abolished.CONCLUSION Escin combined with Dex reduces the dose of Dex,and exerts significant anti-RA effects,which could also reduce the adverse effects of Dex.This combination might be attributed to GR activation.This study might provide a new combination drugs for the treatment of RA.

Forskolin augments the effects of glucocorticoids on proliferation and differentiation of a human osteosarcoma cell line by up-regulation of glucocorticoid receptor

The effect of forskolin, an activator of adenylate cyclase, on glucocorticoid-induced modulation of proliferation and differentiation of a human osteosarcoma cell line(HOS-8603) was iniually studied. It was found that forskolin could significantly augment

Studies on the function and regulation of low－affinity glucocorticoid receptor

In this report we studied the relationship between hydrocortisone(F) concentration and its inductive effect on tyrosine aminotransferase (TAT) activity in primary cultures of rat hepatocytes, and the regulation of rat liver high- and low-affinity glucocorticoid receptors (GRH and GRL) by glucocorticoids (GC). When F concentration was 1-10 nmol/L, the dose-response relationship showed a tendency of saturation. TAT activity was much higher when F concentration was between 10 nmol/L and 10 μmol/l. When F concentration reached 10 μmol/L the induction of TAT could be completely inhibited by RU486, a competitive antagonist of GRH and GRL. These results indicate that induction of TAT by high F concentration was mediated by GRL. The concentration of GC in plasma remained over 10-6 mol/L for 3 d by subcutaneous injection of F in polyvinyl alcohol into the rats. The binding capacity (Ro) of GRH decreased significantly 1 h after injection and remained at a low level,while Ro of GRL increased at 1 h, 24 h, 48 h after injection. It may be concluded that GC could down-regulate GRH and up-regulate GRL. The pathophysiological and clinical significance of these results is discussed.

Glucocorticoid and mineralocorticoid receptor expression in critical illness:A narrative review

The glucocorticoid receptor(GCR)and the mineralocorticoid receptor(MR)are members of the steroid receptor superfamily of hormone-dependent transcription factors.The receptors are structurally and functionally related.They are localized in the cytosol and translocate into the nucleus after ligand binding.GCRs and MRs can be co-expressed within the same cell,and it is believed that the balance in GCR and MR expression is crucial for homeostasis and plays a key role in normal adaptation.In critical illness,the hypothalamic-pituitary-adrenal axis is activated,and as a consequence,serum cortisol concentrations are high.However,a number of patients exhibit relatively low cortisol levels for the degree of illness severity.Glucocorticoid(GC)actions are facilitated by GCR,whose dysfunction leads to GC tissue resistance.The MR is unique in this family in that it binds to both aldosterone and cortisol.Endogenous GCs play a critical role in controlling inflammatory responses in critical illness.Intracellular GC concentrations can differ greatly from blood levels due to the action of the two 11β-hydroxysteroid dehydrogenase isozymes,type 1 and type 2.11β-hydroxysteroid dehydrogenases interconvert endogenous active cortisol and intrinsically inert cortisone.The degree of expression of the two isozymes has the potential to dramatically influence local GC availability within cells and tissues.In this review,we will explore the clinical studies that aimed to elucidate the role of MR and GCR expression in the inflammatory response seen in critical illness.

Clinical relevance of the glucocorticoid receptor gene polymorphisms in glucocorticoid-induced ocular hypertension and primary open angle glaucoma

AIM: To avoid the side effects of ocular hypertension of glucocorticoid(GC) usage in eye, we must identify susceptible individuals, which exists in about one-third of all population. Further, the majority of all primary open angle glaucoma(POAG) patients show this phenotype.Glucocorticoid receptor(GR) regulates C responsiveness in trabecular meshwork(TM) cells. In this study, single nucleotide polymorphism(SNP) genotyping was used to determine whether there are differences in the Bcl I(rs41423247) and N363S(rs6195) polymorphisms of the GR gene in healthy and POAG patients, and glucocorticoid-induced ocular hypertension(GIOH)populations.METHODS: Three hundred and twenty-seven unrelated Chinese adults, including 111 normal controls, 117 GIOH subjects and 99 POAG patients, were recruited. DNA samples were prepared and the Bcl I and N363 S polymorphisms were screened using real-time polymerase chain reaction(RT-PCR)-restriction fragment length polymorphism(RFLP) analysis. Frequencies of the Bcl I and N363 S polymorphisms were determined and compared using Fisher’s exact test and the Chi-squared test.RESULTS: Only the Bcl I polymorphism was identified in the Chinese Han population. The frequency of the G allele was 21.6 % in normal controls, 18.3% in GIOH patients, and 13.64% in the POAG patients. There was no significant difference in polymorphism or allele frequency in the 3 groups. Furthermore, no N363 S polymorphism was found in the study subjects.CONCLUSION: The Bcl I polymorphisms in GR gene had no association with GIOH and POAG patients, and N363 S polymorphism might not exist in the Chinese Han population. Therefore, the Bcl I polymorphism might not be responsible for the development of GC-induced ocular hypertension or POAG.

Glucocorticoid receptor expression in neonatal rat cortex following recurrent seizures The role in developing brain injury

BACKGROUND： Studies have explored changes in neonatal rat glucocorticoid receptor （GR） expression changes following mature brain injury. OBJECTIVE： To investigate the temporal and special changes of GR during brain development in rats with recurrent seizures. DESIGN, TIME AND SE＇n＇ING： A randomized, controlled animal experiment was performed at the Department of Pediatrics, Second Xiangya Hospital of Central South University, from February 2008 to March 2009. MATERIALS： Rabbit anti-rat GR monoclonal antibody was purchased from Santa Cruz Biotechnology, USA; goat anti-rabbit IgG was purchased from Zhongshan Goldenbridge Biotechnology, China. METHODS： A total of 48 Sprague-Dawley rats, 7 days old, were randomly assigned to control and seizure groups, with 24 animals in each group. Seizures were induced by inhalant flurothyl. MAIN OUTCOME MEASURES： Changes in GR protein expression in the rat cerebral cortex were detected by Western blotting analysis and immunohistochemistry. RESULTS： GR expression in the cerebral cortex of control rats significantly increased with aging （P 〈 0.05）, and varied in the frontal lobe, temporal lobe, and parietal lobe. GR was predominantly expressed in the cytoplasm early and rapidly increased in the nuclei. GR protein expression in the cerebral cortex after seizure was lower in the cytoplasm at 15 days and in nuclear protein at 19 days. CONCLUSION： GR expression displayed temporal and spatial changes in brain development. Recurrent seizures in neonatal rats cause abnormal GR expression and might play an important role in developing brain injury.

Glucocorticoid receptor gene haplotype structure and steroid therapy outcome in IBD patients

AIM: To study whether the glucocorticoid receptor (GR/ NR3C1) gene haplotypes influence the steroid therapy outcome in inflammatory bowel disease (IBD). METHODS: We sequenced all coding exons and flanking intronic sequences of the NR3C1 gene in 181 IBD patients, determined the single nucleotide polymorphisms, and predicted the NR3C1 haplotypes. Furthermore, we investigated whether certain NR3C1 haplotypes are significantly associated with steroid therapy outcomes. RESULTS: We detected 13 NR3C1 variants, which led to the formation of 17 different haplotypes with a certainty of > 95% in 173 individuals. The three most commonly occurring haplotypes were included in the association analysis of the influence of haplotype on steroid therapy outcome or IBD activity. None of the NR3C1 haplotypes showed statistically signifi cant association with glucocorticoid therapy success. CONCLUSION: NR3C1 haplotypes are not related to steroid therapy outcome.

Glucocorticoid receptor regulates expression of microRNA-22 and downstream signaling pathway in apoptosis of pancreatic acinar cells

AIM To elucidate the underlying mechanism that microRNA-22(miR-22) promotes the apoptosis of rat pancreatic acinar cells(AR42 J) and the elements that regulate the expression of miR-22.METHODS One hundred nanomoles per liter of caerulein(Cae)was administrated to induce the apoptosis of AR42 J cells and the apoptosis rate was detected by flow cytometry analysis. An amylase assay kit was used to measure the amylase expression level in the supernatant. Quantitative real-time PCR(qRT-PCR)was adopted to measure miR-22 expression. We used online tools to predict the potential transcription promoter of miR-22 and the binding sites, which was further identified by using luciferase reporter analysis,chromatin immunoprecipitation(ChIP) and ChIPqP CR assays. Then, a mimic of miR-22, Nr3 c1 plasmid encoding the glucocorticoid receptor(GR), and siNr3 c1 were used to transfect AR42 J cells, respectively.The mRNA expression of miR-22, Nr3 c1, and Erb-b2 receptor tyrosine kinase 3(ErbB3) was confirmed by qRT-PCR and the apoptosis rate of AR42 J cells was detected by flow cytometry analysis. Western blot was used to detect the expression of ErbB3, GR, PI3 k, PI3 kp85α, Akt, p-Akt, Bad, Bax, Bcl-xl, Bcl-2, and cleaved caspase3.RESULTS After inducing apoptosis of AR42 J cells in vitro, the expression of miR-22 was significantly increased by2.20 ± 0.26 and 4.19 ± 0.54 times, respectively, at3 h and 6 h in comparison with the control group.As revealed by qRT-PCR assay, the expression of miR-22 was 78.25 ± 6.61 times higher in the miR-22 mimic group relative to the miRNA control group,accompanied with an obviously increased acinar cell apoptosis rate(32.53 ± 1.15 vs 18.07 ± 0.89, P =0.0006). The upregulation of miR-22 could suppress its target gene, ErbB3, and the phosphorylation of PI3 k and Akt. Furthermore, we predicted the potential transcription promoter of miR-22 and the binding sites using online tools. Luciferase reporter analysis and sitedirected mutagenesis indicated that the binding site(GACAGCCATGTACA) of the GR, which is encoded by the Nr3 c1 gene. Downregulation of the expression of GR could upregulate the expression of miR-22, which further promoted the apoptosis of AR42 J cells.CONCLUSION GR transcriptionally represses the expression of miR-22,which further promotes the apoptosis of pancreatic acinar cells by downregulating the downstream signaling pathway.

Effect of Calpain inhibitor I on glucocorticoid receptor-dependent degradation and its transactivation ability

Objective: To investigate the effect of Calpain inhibitor I on glucocorticoid receptor-dependent proteasomal degradation and its transcriptional activity. Methods: After Raw-264.7 cells were treated with Calpain inhibitor I, dexamethasone, or both for about 12 h, the change of glucocorticoid receptor was detected by western blot analysis. COS-7 cells were transfected with PRsh-GRα expression vector and glucocorticoid-responsive receptor pMAMneo-CAT, then the effect of Calpain inhibitor I on glucocorticoid receptor transcriptional activation ability was determined by CAT activity. Results: The glucocorticoid receptor levels decreased after RAW-264.7 cells were treated with dexamethasone for 12 hours, which effect can be inhibited by Calpain inhibitor I to some extent. CAT activity assay showed that Calpain inhibitor I enhance glucocorticoid receptor transcriptional activity. Conclusion: Calpain inhibitor I can inhibit the down-regulation of dexamethasone on glucocorticoid receptor, and enhances glucocorticoid receptor transactivation ability.

Novel insights into the effect of Xiaoyao san on corticosterone-induced hepatic steatosis:inhibition of glucocorticoid receptor/perilipin-2 signaling pathway

Objective:Xiaoyao san(XYS)is a classic traditional Chinese medicinal formula.It has been clinically administered to regulate liver function.However,its mechanisms in glucocorticoid-induced hepatic steatosis are unknown.This study aimed to investigate whether XYS protects against corticosterone(CORT)-induced hepatic steatosis,and to explore its mechanism.Methods:High-fat diet mice induced with hepatic steatosis by 2mg/kg CORT were administered 2.56 g/kg or 5.12 g/kg XYS daily for 7 weeks.The effects of XYS on hepatic steatosis in mice were evaluated by H&E and Oil Red O staining and by measuring their plasma lipids(triglyceride,total cholesterol,and free fatty acids).The mechanism of XYS against hepatic steatosis was investigated by network pharmacology,immunohistochemistry,western blotting,and gain-of-function/loss-offunction experiments.Results:XYS alleviated CORT-induced steatosis,decreased plasma lipids,and inhibited glucocorticoid receptor(GR)activation in the liver.Network pharmacology data indicated that XYS may have mitigated hepatic steatosis via GR which mediated adipose differentiation-related protein(ADFP).Gain-of-function/loss-of-function experiments in vitro confirmed that GR positively regulated ADFP expression.Conclusions:XYS ameliorated CORT-induced hepatic steatosis by downregulating the GR/ADFP axis and inhibiting lipid metabolism.Our studies implicate that XYS is promising as a therapy for CORT-induced hepatic steatosis,and lay the foundation for designing novel prophylactic and therapeutic strategies on CORT-induced hepatic steatosis.

Study on glucocorticoid receptor of brain cytosol in rats with traumatic brain edema

The high-affinity glucocorticoid binding sites（HAGS）and the low-affinity glucocor-ticoid binding sites（LAGS）with steroid specificity were demonstrated in cerebral cytosol ofrats by using the radioligand binding assay.The equilibrium dissocation constant（Kd）of HAGSand LAGS were（2.78+0.71）×10-8mol/L and（2.12±1.06）×10-6mol/L respectively as esti-mated by Scatchard and Pseudoseatchard analysis.Glucocorticoid receptors（GR）in the trau-matized（left）hemisphere cytosol were decreased more significantly than those in both the con-trol（right）hemisphere cytosol at 6 h postinjury and normal brain tissue（P【0.05）,but Kd ofGR showed no significant changes.GR of liver cytosol at 6h postinjury were more markedly de-creased than normal hepatic cytosol,but Kd of GR underwent no significant changes.These da-ta demonstrate that high-dose glucocorticoid（GC）used in the treatment of traumatic brain ede-ma might maintain target-cell reactions by increasing the production of GC receptor complexesand is most likely to be mediated by LAGS.

Effects of glucocorticoid and glucocorticoid receptors on stress-induced neurogenesis suppression

Studies have shown that cerebral ischemia activates neurogenesis and that stress inhibits neurogenesis.However,the role of stress hormone levels on neurogenesis following cerebral ischemia remains poorly understood.The present study explored the possible regulatory mechanisms of adult neurogenesis under pathological conditions by examining changes and regulation of glucocorticoid receptors in adult rats subjected to transient unilateral middle cerebral artery suture occlusion.Corticosterone levels gradually increased following middle cerebral artery occlusion,and the number of glucocorticoid receptor-positive cells decreased.The number of5-bromodeoxyuridine-and nestin-positive cells significantly increased at 1 and 2 weeks after ischemia.A large number of doublecortin-positive cells migrated from the hippocampus to the cortex.At 3 weeks post-surgery,the number of 5-bromodeoxyuridine-and nestin-positive cells significantly reduced in the subventricular zone.Increased corticosterone levels decreased vascular endothelial cell proliferation and neurogenesis,and the number of glucocorticoid receptor-positive cells decreased.In the sham surgery group,vascular endothelial cell proliferation related to post-ischemic cerebral rehabilitation was not detected.Corticosterone levels increased,but the number and distribution of glucocorticoid receptor-positive cells were not changed.However,normal neuregenesis and migration of neural stem cells existed in the adult rat brain in the sham surgery group.Results suggested that glucocorticoid receptors influenced neurogenesis and were negatively regulated by glucocorticoid levels following focal cerebral ischemia and reperfusion.

GLUCOCORTICOID RECEPTOR IN CHILDHOOD ACUTE LYMPHOBLASTIC LEUKEMIA

Objective: To investigate the relationship among glucocorticoid receptor (GCR) level, immunological classification and clinical efficacy of chemotherapy in acute lymphoblastic leukemia (ALL) children. Methods: The GCR level of venous blood lymphocytes was measured by receptor radioligand binding assay in 50 cases with childhood ALL and 41 normal children. The immunological classification of 32 children with ALL was analyzed by ABC immunoenzymatic method. Results: The GCR number in venous blood lymphocytes of normal children was 4651±1617 binding sites/cell. The normal range (95%) was 1482–7800 binding sites/cell. The GCR level of 50 cases with ALL (6695±5256 binding sites/cell) was significantly higher than that of the normal ones (t=2.50, P<0.05). The GCR level of the ALL children with good prognosis was significantly higher than that of bad prognosis (t=4.39, P<0.001). The relationship between immunological classification and GCR level of 32 cases with children ALL was as follows: GCR level of T-ALL and B-ALL were significantly lower than AUL, C-ALL and pre-B-ALL; the prognosis of T-ALL and B-ALL was also bad; the GCR level of the group with good prognosis was significantly higher than that with bad prognosis in all immunological types. Conclusion: The GCR level of the peripheral venous blood lymphocytes in children ALL may be an important biochemistry indicator and used to predict prognosis and guide combination chemotherapy. The relationship between GCR and immunological classification can be useful to the expectation of prognosis.

Down-regulation of glucocorticoid receptor mRNA by glucocorticoids in rats

The effect of glucocorticoids on the down-regulation of glucocorticoidreceptor (GR) mRNA was studied in intact rats.GR mRNA was characterized byNorthern blot hybridization and quantitated by dot blot hybridization using a hu-man GR cDNA fragment as a probe.Administration of hydrocortisone (F) inpolyvinyl alcohol (PVA) resulted in a rapid increase in plasma glucocorticoidswhich maintained at stress levels (20 to 40μg/dl) for about 3 d.HepaticGR mRNA decreased significantly to 73.5±6.3% of control values 6h followingF treatment,after which the decline of GR mRNA was gradual,reaching a mini-mum of 44.0±5.0% of control levels 3d after the treatment.The effect of F onthe down-regulation of hepatic GR mRNA lasted up to 11 d.In contrast,F treat-ment had no effect on GR mRNA in rat brain.These results are consistent withthe changes in GR in rats as reported previously,except that even though thehepatic cytosol GR decreased markedly,no significant changes in hepatic GRmRNA were found 1h after F treatment,strongly suggesting that thedown-regulation of GR by its ligands in vivo occurs at both transcriptional andposttranscriptional levels and is of tissue-specific fashion.