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Abstract The growth hormone receptor (GHR) mediates the effect of growth hormone (GH) on linear growth and metabolism. In humans, it exists as two isoforms differing by the retention or exclusion of exon 3; a full-length GHR isoform (GHRfl) and the exon 3-deleted isoform (GHRd3). The genotypic frequency of this polymorphism was analyzed in several studies and in different human populations. However scarce information in Argentinean population is available. Associations between GHRd3 and growth have been reported previously. Some studies have shown that the presence of GHRd3 polymorphism might be a potential variant that improves growth response to recombinant human GH (rhGH) therapy in patients born small for gestational age (SGA), among others. However, over the years the results have been controversial and inconclusive. Based on this, it would be proposed that variants at the genomic level are not completely reflected at the mRNA level. Our aim was to evaluate the genotypic frequencies (%) of the GHR gene polymorphism (GHRfl/GHRfl; GHRfl/GHRd3; GHRd3/GHRd3) in normal Argentinean population (n = 94) and SGA patients (n = 65), and the expression of these polymorphisms at mRNA level in the fetal side of placenta tissues was analyzed. In addition, their asso ciation with spontaneous postnatal catch-up growth in SGA patients was also evaluated. In this study, we show a significant increment of compensatory growth in small for gestational age children (SGA) associated to the presence of the GHRd3 allele polymorphism. In addition, the expression of GHR in healthy placentas revealed that no alternative splicing mechanism occurs.
Resumen El receptor de la hormona de creci miento (GHR) media la acción de la hormona de crecimiento (GH) en el crecimiento lineal y el metabolismo. En los seres humanos, existen dos isoformas que difieren en la retención (GHRfl) o exclusión del exón 3 (GHRd3). La frecuencia genotípica de este polimorfismo fue analizada en varios estudios y en diferentes poblaciones. Sin embargo, la información disponible en la población argentina es escasa. Se ha reportado anteriormente asociación entre el polimorfismo GHRd3 y el crecimiento. Varios estudios ha n demostrado que la presencia del polimorfismo GHRd3 podría mejorar, en pacientes nacidos pequeños para la edad gestacional, entre otros, la respuesta a la terapia con GH humana recombinante (rhGH). Sin embargo, a lo largo de los años los resultados han sido con trovertidos y no concluyentes. En base a esto, se propondría que las variantes a nivel genómico no se reflejan completamente a nivel del ARNm. Nuestro objetivo fue evaluar la frecuencia genotípica de los polimorfismos del gen del GHR (GHRfl/GHRfl; GHRfl/GHRd3; GHRd3/GHRd3) en la población argentina normal (n = 94) y en niños pequeños para la edad gestacional (n = 65), y se analizó la expresión de estos polimorfismos a nivel de ARNm en la porción fetal de placentas sanas. Además, se evaluó la asociación de este polimorfismo con el cre cimiento postnatal espontáneo en pacientes pequeños para la edad gestacional. En este estudio, mostramos un incremento significativo del crecimiento compensatorio en niños pequeños para la edad gestacional asociado a la presencia del polimorfismo del alelo GHRd3. Además, los ensayos de expresión de GHR en placentas sanas revelaron que no se produciría ningún mecanismo de splicing alternativo.
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Humans , Female , Pregnancy , Child , Receptors, Somatotropin/genetics , Human Growth Hormone , Polymorphism, Genetic , Carrier Proteins , Exons , Gestational AgeABSTRACT
Objective Studies on the location of the susceptibility genes of mandibular prognathism are mostly conducted by association analysis. The aim of this study was to investigate the correlation between the single nucleotide polymorphism (SNP) of the candidate gene of the growth hormone receptor (GHR) and mandibular prognathism in the Han Chinese in Hong Kong. Methods We selected 7 tag SNPs (tSNP) in the GHR gene from 211 cases of mandibular prognathism and 224 controls among the Han Chinese in Hong Kong. We genotyped the tSNPs using the MassARRAY System and analyzed the association of individual SNPs and the relevant haplotypes with mandibular prognathism. Results The SNP rs6898743 of the GHR gene was found associated with mandibular prognathism in genotypic frequency (P = 0.036) and allelic distribution (P = 0.015), and the G allele of rs6898743 associated with a significantly decreased risk of mandibular prognathism (OR: 0.72; 95% CI: 0.55-0.94). Linkage disequilibrium analysis revealed the association of mandibular prognathism with the haplotypes GAA (P = 0.014) and GAG (P = 0.012). Conclusion The SNP locus rs6898743 of the GHR gene is associated with mandibular prognathism in the Han Chinese in Hong Kong
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AIM:To investigate the effect of growth hormone receptor(GHR) knockdown on nuclear factor-κB (NF-κB) activity and inflammatory cytokine production stimulated by growth hormone (GH) in 3T3-L1 adipocytes. METHODS:The specific siRNA for GHR was transfected into 3T3-L1 adipocytes to silence GHR expressions. The effects of GH on NF-κB activation and inflammatory cytokine production in 3T3-L1 adipocytes transfected with siRNA-GHR or siRNA-control were measured by dual-luciferase system analysis,real-time RT-PCR and ELISA. RESULTS:The protein expression of GHR was diminished after transfection with GHR specific siRNA. Dual-luciferase reporter system analysis re-vealed that GHR knockdown resulted in attenuation of GH-stimulated NF-κB activation in the 3T3-L1 adipocytes. GHR knockdown ameliorated the GH-induced production of inflammatory cytokines TNF-α,IL-1β,IL-6,MCP-1 and MIP-1α in the 3T3-L1 adipocytes. CONCLUSION:Knockdown of GHR might be efficacious to prevent GH-induced inflammatory re-sponses in the 3T3-L1 adipocytes.
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BACKGROUND: This study investigated the association between the frequency of growth hormone receptor (GHR) exon 3 polymorphism (exon 3 deletion; d3-GHR) and metabolic factors in patients with acromegaly in Korea. METHODS: DNA was extracted from the peripheral blood of 30 unrelated patients with acromegaly. GHR genotypes were evaluated by polymerase chain reaction and correlated with demographic data and laboratory parameters. RESULTS: No patient had the d3/d3 genotype, while four (13.3%) had the d3/fl genotype, and 26 (86.7%) had the fl/fl genotype. Body mass index (BMI) in patients with the d3/fl genotype was significantly higher than in those with the fl/fl genotype (P=0.001). Age, gender, blood pressure, insulin-like growth factor-1, growth hormone, fasting plasma glucose, triglycerides, high density lipoprotein cholesterol, and low density lipoprotein cholesterol levels showed no significant differences between the two genotypes. CONCLUSION: The d3-GHR polymorphism may be associated with high BMI but not with other demographic characteristics or laboratory parameters.
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Humans , Acromegaly , Blood Glucose , Blood Pressure , Body Mass Index , Cholesterol, HDL , Cholesterol, LDL , DNA , Exons , Fasting , Genotype , Growth Hormone , Korea , Polymerase Chain Reaction , Receptors, Somatotropin , TriglyceridesABSTRACT
Objective To investigate the influence of tissue-specific growth hormone receptor (GHR)deficiency in type 1 diabetes in the mice at the gene level using pancreaticβcells combined with streptozotocin (STZ)-induced type 1 diabetes model.Methods The experiment was divided into four groups:knockout mice group (LLc knockout group), using the homozygotes (LLc:LL+Cre) producted by pancreaticβ cell-specific expressed recombinant enzyme mice (RIP-Cre)and Cre-LoxP system modified GHR mice (Floxed,LL);LL control group, containing Floxed GHR allele homozygous mice (LL);LLc STZ group and LL STZ group (STZ was used for inducing type 1 diabetes model mice). The mice with feeding glucose≥25 mmol · L-1 were considered to be successful models.The Glucose Tolerance Test (GTT),pancreas tissue HE staining and immunohistochemistry were performed in the mice.Results The blood glucose of the mice in LL STZ group and LLc STZ group and LLc STZ group were increased after inj ection of STZ and the models achieved the diagnostic criteria for diabetes 1 6 d later.The results of GTT showed that compared with LLc control group and LLc knockout group, the blood glucose levels of the mice in LL STZ and LLc STZ groups were increased (P<0.05).There was no significant change of morphology and structure of islets between LL control group and LLc knockout group detected by HE staining. The immunohistochemistry results showed that the insulin level of the mice in LL STZ group was significantly reduced compared with LL control group;the insulin level of the mice in LLc STZ group was reduced compared with LLc control group.Conclusion Pancreaticβcell GHR gene knockout has no effect on the blood glucose and the function ofβcells in the mice with STZ-induced type 1 diabetes.
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With deeper studies on the endocrine axis of growth hormone-releasing hormone-growth hormone-insulin-like growth factor(GHRH-GH-IGF-1),the correlation between molecular analysis of the growth hormone receptor (GHR) gene,nucleoside acid polymorphism and idiopathic short stature(ISS) have been explored gradually.The GHR gene abnormalities often occurred in extracellular domain of GHR proteins,resulting in dysfunction of intracellular signal transduction of GHR.When the growth hormone couldn't play a role or be insensitive fully,the ISS happened.As reported,GHR single nucleotide polymorphisms(SNP),particularly the GHR-exon3 polymorphisms,have closely correlated with the susceptibility to ISS.GHR gene abnormalities and SNP often have been related to the levels of serum IGF-1 and growth hormone binding protein,and the response of recombinant human growth hormone therapy.The screening candidate genes like GHR gene in ISS,the expression of functional protein and analysis of SNP can improve level of genetic diagnosis,and would be important for clearing the etiology and regulating the clinical treatment of ISS.
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ObjectiveTo investigate the effect of recombinant human growth hormone (rhGH) on JAK2-STAT3 signaling pathway and on the growth of human colon cancer cells at different growth hormone receptor (GHR) expression status.MethodsLOVO and HCT-8 cell lines were selected after the colon cancer cells were screened using flow cytometry according to the GHR expression status.The growth of human colon cancer cells after intervention with rhGH was detected by MTT assay.The proliferation index ( PI),cell cycle,and apoptosis were detected by flow cytometry.The expression of JAK2-STAT3 signaling pathway proteins was detected by Western blot.ResultsHCT-8 cell line showed positive GHR expression (59.6％),and LOVO cell showed negative GHR expression (3.5％).The growth rate of HCT-8 cells increased after rhGH treatment.Compared with the untreated HCT-8 cells,the rhGH-treated HCT-8 cells showed reduced apoptosis,elevated PI,and increased G2/Mphase cells ( P =0.0073).Western blot revealed that rhGH up-regulated the proteins of pJAK2,pSTAT3,VEGF,Cyclin D1,and Bcl-xL in HCT-8 cells.In contrast,no such changes were observed in LOVO cells treated with rhGH.ConclusionsrhGH may promote the growth of HCT-8,the cell line of high GHR expression,and up-regulate the expression of a number of key nodes in JAK2-STAT3 signaling pathway.However,rhGH may not affect LOVO,the cell line of low GHR expression.
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Objective To detect the expression of GHR in colorectal cancer cell lines and determine whether recombinant human growth hormone can promote the proliferation of colorectal cancer cells in vitro.Methods GHR distribution was assessed by flow cytometry and immunofluorescence method in 9 colorectal cancer cell lines.The effect of recombinant human growth factor on colorectal cancer cell line proliferation was assessed by MTT method.Results Different GHR expression was determinated in 9 colorectal caner cell lines.GHR was highly expressed in HCT-8 while GHR expression could hardly be detected in LoVo.r-hGH could promote GHR(+) HCT-8 cell proliferation at 50 ng/ml and 100 ng/ml (P ＜0.05).But this effect was not dose dependent.When the neutralizing antibody was used to block GHR activity,this r-hGH dependent proliferation effect was eliminated.r-hGH could not promote GHR (-) LoVo cell proliferation (P ＞0.05).Conclusion The results demonstrates that r-hGH could promote GHR (+) tumor cell proliferation and this effect is mediated by GHR.The use of r-hGH on the colorectal cancer patients should be cautious.
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Objective To investigate the effects of recombinant human growth hormone (rhGH) on tumor growth and tumor angiogenesis factor relevant to Janus kinase 2-signal transducer and activator of transcription 3 of human gastric carcinoma xenografts in nude mice with different expressions of growth hormone receptor (GHR).Methods Immunocytochemical method was used to pick out one GHR-positive and one GHR-negative cell line. The cells were subcutaneously injected into 26 nude mice separately, then the patterns of xenografts in nude mice with different expressions of GHR were established. The nude mice bearing two different kinds of human gastric caicinoma were equally randomized into control group, low-dose rhGH group, and high-dose rhGH group,and were treated with drugs for 14 days. Changes of tumor volumes and body weight of nude mice were record. The protein and mRN A expressions of tumor angiogenesis factor in tumor tissue were detected by RT-PCR and Western blot, respectively. Results GHR was highly expressed in SGC-7901 celk but negative in MKN-45 cells. For nude mice bearing GHR+ SGC-7901 xenografts, the tumor volumes were significantly larger in low-dose rhGH group [(1. 141 ±0. 234) cm3] and high-dose rhGH group [(2. 106 ±0. 260) cm3] than in control group [(0.612±0. 156) cm3] (P = 0. 034, P = 0. 001), and the high-dose rhGH group revealed greater effect (P =0. 043 ). Body weight was not significantly different among three groups. Compared with the control group, the mRNA expressions of tumor angiogenesis factor were significantly increased in low-does rhGH group, and the P values of GHR, Janus kinase 2, signal transducer and activator of transcription 3, vascular endothelial growth factor (VEGF), hypoxia-inducible factor-1α (HIF-1α), fibroblast growth factor, and matrix metalloproteinases-2 (MMP-2) was 0.001, 0.011, 0.042, 0.045, 0.040, 0.002, and 0.003, respectively; however, the high-does rhGH group did not show the greater effects. The protein expressions were significantly increased in low-does rhGH group, and the P value of phosphorylation-signal transducer and activator of transcription 3, signal transducer and activator of transcription 3, VEGF, HIF-1α, and MMP-2 was 0. 015, 0.003, 0.010, 0.008,and 0. 005, respectively; furthermore, the high-does group revealed the further greater effects, and the P value of VEGF, HIF-1α, and MMP-2 was 0.012, 0.025, and 0.046, respectively. On the contrary, for nude mice bearing GHR- MKN-45 xenografts, the body weights of low-dose rhGH group [(24.94 ±0. 517) g] and high-dose rhGH group [(26.97 ±0.686) g] were significantly higher than that of control group [(22.78 ±0.418) g] (P =0. 040, P = 0.012 ) , while tumor growth as well as the expressions of mRNA and protein of tumor angiogenesis factor in tumor tissue were not significantly different Conclusions rhGH can promote tumor growth and up-regulate the expression of tumor angiogenesis factor in the GHR-highly-expressed SGC-7901 xenograft tumor model; However,such effects do not exist in GHR-negatively-expressed MKN-45 xenograft tumor model. The existence of GHR may be a key target by which rhGH influences the tumor growth and the expressions of tumor angiogenesis factor, which is probably achieved through Janus kinase 2-signal transducer and activator of transcription 3 activation.
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@#Objective To investigate the effects of recombinant human growth hormone (rhGH) on tumor growth and vascular endothelial growth factor (VEGF) expression of human gastric carcinoma xenografts in nude mice with different expressions of growth hormone receptor (GHR). Methods Immunocytochemical method was used to pick out one GHR-positive and one GHR-negative cell line. Then the cells were subcutaneously injected into 24 nude mice separately. The nude mice bearing two different kinds of human gastric caicinoma were equalges of body weight and tumor volume of nude mice were recorded. Serum concentrations of VEGF in peripheral blood were analyzed by ELISA. VEGF protein and mRNA expression in tumor tissue were detected by immunohistochemistry and RT-PCR, respectively. Results We chose SGC-7901 as GHR positive group, and MKN-45 as the negative one. For nude mice bearing GHR + SGC-7901 xenografts, the tumor volumes were significantly larger in rhGH groups than in control group (P ＜ 0.05), and the high-dose rhGH group revealed greater effect (P ＜ 0. 05).Body weights were not significantly different among three groups (P ＞ 0. 05). Serum VEGF concentration was (252.94 ± 15.32) ng/L in the high-dose rhGH group, which was significantly higher than that in control group [(49.94 ± 5.73) ng/L] and low-dose rhGH group [(167.60 ± 9.54) ng/L] (P ＜ 0.05). Moderate positive staining with VEGF was observed in the control group, while VEGF staining was strong in rhGH administration groups. The relative expression of VEGF mRNA for the high-dose rhGH group was 0. 6470 ± 0. 0447, which was significantly higher than that in control group (0. 3230 ± 0. 0258)and low-dose rhGH group (0. 412 ± 0. 0351)(P ＜ 0.05). While for nude mice bearing GHR-MKN-45 xenografts, the body weights of the rhGH-administrated groups were significantly higher than that of control group (P ＜ 0.05), while tumor growth, serum VEGF concentration, and the expressions of VEGF mRNA and protein in tumor tissue were not significantly different (P ＞ 0.05).Conclusions rhGH can promote tumor growth and increase the expression of VEGF in the GHR-highly-expressed SGC-7901 xenograft tumor model. However, such effects do not exist in GHR-negatively-expressed MKN-45 xenograft tumor model. The existence of GHR may be a key target where rhGH influences the secretion of VEGF.
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Objective To eonstruct three eukaryotic expression vectors containing wilde-type hGHR gene and its mutants(hGHR-E42K and hGHR-H56R) related to congenital growth hormone insensitivity, then check their expression in CHO cells. Methods With the available PUC-hGHR vector, two mutate hGHR genes (hGHR-E42K and hGHR-H56R) were obtained through mutagenesis. Then three recombinants were cloned into eukaryotic expression vectors pcDNA3.1/zeo(+) with restriction enzymatic reactions.Then with Lipofectamine2000, we trans-fected expression vectors to CHO cells and screened the stably expressed CHO cells by Zeocin. RT-PCR and/or Western blotting were used to examine hGHR and STAT5-P. Results After sequencing, two mutations were introduced to hGHR, three eukaryotic expression vectors were identified. The transfected CHO cells expressed vd-hGHR or its mutants. Compared with hGH-wt, two mutate cells (E42K and H56R) had decreased phosphorylated STAT5 levels. Conclusion Three CHO cells which stably expresses wide type hGHR and its mutants were successfully established, E42K and H56R partly interfered the phosphorylation of STAT5.
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01 and SMMC7721 in which the expression of GHR was low or undetectable in vitro.
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Objective To construct three eukaryotic expression vectors containing wilde-type hGHR gene and its mutants(hGHR-E42K and hGHR-H56R) related to congenital growth hormone insensitivity,then check their expression in CHO cells. Methods With the available PUC-hGHR vector,two mutate hGHR genes (hGHR-E42K and hGHR-H56R) were obtained through mutagenesis. Then three recombinants were cloned into eukaryotic expression vectors pcDNA3.1/zeo(+) with restriction enzymatic reactions. Then with Lipofectamine2000,we transfected expression vectors to CHO cells and screened the stably expressed CHO cells by Zeocin. RT-PCR and/or Western blotting were used to examine hGHR and STAT5-P.Results After sequencing,two mutations were introduced to hGHR,three eukaryotic expression vectors were identified. The transfected CHO cells expressed wt-hGHR or its mutants. Compared with hGH-wt,two mutate cells (E42K and H56R) had decreased phosphorylated STAT5levels. Conclusion Three CHO cells which stably expresses wide type hGHR and its mutants were successfully established,E42K and H56R partly interfered the phosphorylation of STAT5.
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Objective: To investigate the effect of zinc sulfate and zinc methionine on growth and their possible regulating mechanism in mice. Method: Ninety male KM mice were randomly divided into three groups. The control group was fed on basal diet containing zinc of 11. 67 mg/kg 10d. The ZnSO4 group and Zn-Met group were fed on the diets supplemented with ZnSO4 or Zn-Met at 30 mg/kg(on the basis of Zn) for 10 d. Initial and final body weight,serum zinc concentration, growth hormone (GH),the levels of growth hormone receptor (GHR) and insulin like growth factor 1 (IGF-1) mRNA were determined. Results: Both ZnSO4 and Zn-Met enhanced body weight and serum zinc concentration of mice,Zn-Met more effectively than ZnSO4 for body weight . Both forms of zinc had no effect on GH and the expression of GHR mRNA , but both up-regulated the expression of IGF-1 mRNA. As compared to ZnSO4, Zn-Met enhanced the level of IGF-1 mRNA significantly. Conclusion: Both ZnSO4 and Zn-Met had no effect on GH and the expression of GHR Mrna,but enhanced the expression of IGF-1 mRNA. Zn-Met enhanced the body weight gain and up-regulated IGF-1 mRNA expression more effectively than ZnSO4.
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PURPOSE: Children with idiopathic short stature(ISS) are classified on the basis of exclusion criteria. Short stature with normal or increased circulating growth hormone(GH) and low IGF-I levels indicates that partial growth hormone insensitivity(GHI) may play a role in ISS. The present study was performed to investigate whether partial GHI is observed in children with idiopathic short stature and whether partial GHI is related to growth hormone receptor(GHR) defect. METHODS: Twenty-five children with ISS were studied and 30 normal children were enrolled as control. Anthropometric measurement and IGF-I generation test were performed. The GHR gene was amplified by PCR, from leukocyte-derived DNA and sequenced directly. RESULTS: IGF-I level was increased after GH treatment, but there was no significant correlation between delta IGF-I and delta HTSDS, as well as between delta IGFBP-3 and delta HTSDS indicating partial GHI in children with ISS. When GHR genes were analyzed, polymorphism was observed. That is, adenine which is third base for 168 th amino acid was guanine. Furthermore this finding was observed in 100% of 55 children examined, which was a rather higher incidence compared to previous reports from other country. The first base of 526 th amino acid was either adenine or cytosine or heterozygous of adenine and cytosine, suggesting an occurrence of I526L variant. Deletions of one or two bases in flanking region of exon 3 and 8 were confirmed in Koreans, the same as it occurs in Japanese. There are differences in the sequences of human GHR gene among different ethnic populations. Wide variations of phenotype in ISS cannot clearly be explained by GHR gene alone. Variations or polymorphism of GHR genes remains to be functionally analysed. CONCLUSION: ISS might be due to the partial GHI which is resuls from mutation of GHR genes.
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Child , Humans , Adenine , Asian People , Cytosine , DNA , Exons , Growth Hormone , Guanine , Incidence , Insulin-Like Growth Factor Binding Protein 3 , Insulin-Like Growth Factor I , Phenotype , Polymerase Chain Reaction , Receptors, SomatotropinABSTRACT
PURPOSE: The growth hormone receptor(GHR) is essential for the actions of growth hormone on postnatal growth and metabolism. GHR transcripts are characterized by the presence of disparate 5'untranslated exons. In contrast to L1 transcript, factors regulating the expression of the GC rich L2 transcript have remained unidentified. The purpose of this study is in order to characterize the mechanisms regulating expression of the L2 transcript in the murine GHR gene METHODS: Transient transfection experiments including deletional analysis and co-transfection assay were performed to find a region containing promoter activity in the L2 5'flanking sequence using BNCL2(mouse liver) cells, CV-1(African green monkey kidney) cells, HRP.1 trophoblasts and Drosophila Schneider(SL2) cells. Sequencing analysis was performed to find the region contained consensus binding sites for transcription factors. Standard gel shift(Electrophoretic mobility shift assay, EMSA) and supershift analysis using liver nuclear extracts was performed to establish proteins(transcription factors) bound this regulatory element. RESULTS: The 5'flanking region of the L2 untranslated region(UTR) exhibited promoter activity in BNCL2(mouse liver), CV-1(monkey kidney) cells and HRP.1 trophoblasts. Deletional analyses indicated the presence of a Sp binding site important for transcription of the L2 UTR and localized the major regulatory region within 75 bp of the 5'transcription start site. Sequencing analyses revealed the region contained consensus binding sites for the Sp family of transcription factors. EMSA and supershift EMSA revealed that in mouse liver nuclear extracts that Spl and Sp3 bound to this cis-element. Functional studies in Drosophila SL2 cells and BNCL2(mouse liver) cells established the ability of Sp3 and Sp1 to stimulate transcriptional activity via this cis-element. Functional studies in Drosophila SL2 cells demonstrated a functional interaction between Sp3 and Sp1 at this DNA-binding site. CONCLUSION: Sp family transcription factors play a role in regulation of L2 transcript gene expression in the 5'flanking region of the murine GHR gene.
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Animals , Humans , Mice , Binding Sites , Chlorocebus aethiops , Consensus , Drosophila , Electrophoretic Mobility Shift Assay , Exons , Gene Expression , Growth Hormone , Liver , Metabolism , Receptors, Somatotropin , Regulatory Sequences, Nucleic Acid , Transcription Factors , Transfection , TrophoblastsABSTRACT
Objective:To investigate the effect of recombinant human growth hormone(rhGH) on colorectal cancer cell lines radiosensitivity.Methods:The GHR positive HCT-8 and GHR negative LOVO cell lines were used and each cell set was divided into 3 groups,which were radiation along,radiation + rhGH group and radiation + rhGH + GHRA(GHR neutralizing antibodies) group.The classical colony forming assay was performed to measure the post-radiation colorectal cancer cell proliferation as an indicator of radiosensitivity.Flow cytometry was used to detect the radiation induced apoptosis.Comet assay was performed to detect the radiation induced DNA damage.The radiation dose was 2 Gy,4 Gy,and 8 Gy respectively.The rhGH concentration used was 100 ng/mL while GHRA was 0.2 ug/mL.Results:The colony formation rate was significantly enhanced in HCT-8 cells pre-incubated with rhGH compared to the radiation group cells.Under the radiation of high dose(8 Gy),this effect was more obvious(52.1 2.9 vs 21.0 2.7,P
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Objectives:To investigate the role of endotoxin, TNF ? and IL 6 in inducing the growth hormone insensitivity at the receptor and post receptor levels. Methods:Spague Dawley rats were injected with endotoxin, TNF ?, and IL 6 respectively and were killed at different time points. The liver expressions of IGF 1, GHR and SOCS 3 mRNA were detected by RT PCR, the GH levels were measured by radioimmunoassay,and the levels of TNF ? and IL 6 were detected by ELISA. Results:Serum growth hormone levels at each time points after LPS iv injection did not have significant changes compared with control rats without iv injection of LPS, TNF ? and IL 6 levels were elevated rapidly after LPS injection, but TNF ? levels returned to normal quickly. The most remarkable down regulations for liver IGF 1 mRNA and GHR mRNA occurred at 12h and 8h respectively after LPS infusion. The liver SOCS 3 mRNA was weakly expressed in control rats. However, it was strongly up regulated after LPS injection and had a 7.84 times increase at 1h. The linear regression analysis had shown a positive correlation between IL 6 levels and liver SOCS 3 mRNA expressions. Liver GHR mRNA expression was obviously down regulated after TNF ? iv injection, but there was no effect on liver SOCS 3 mRNA expression. IL 6 up regulated the liver SOCS 3 mRNA expression, but it could not affect the liver GHR mRNA expression. Conclusions:The growth hormone insensitivity could be induced by LPS injection, which was associated with down regulated GHR mRNA expression at receptor level and up regulated SOCS 3 mRNA expression at post receptor level. The biological activities of LPS are mediated by TNF ? and IL 6 indirectly.And TNF ? and IL 6 exert their effects on the receptor and post receptor levels respectively, but the effect of TNF ? is of hysteresis.
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Acquired growth hormone resistance(AGHR) in critical illness may be defined as the combination of a raised serum growth hormone concentration,low serum insulin-like growth factor-1 concentration and a reduced anabolic response to exogenous GH.GH given to reverse catabolism in critical illness increased mortality.Therefore,it has the theoretical significance and clinical value for better understanding of the mechanism of AGHR.The mechanism of AGHR and its prevention and cure are reviewed.
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Objective To investigate the effects of malnutrition, nephrosis itself and glucocorticoid therapy on serum growth hormone binding protein(GHBP) and liver growth hormone receptor(GHR), and elucidate the relationship between growth failure in nephrotic rats and serum GHBP or liver GHR. Methods Twenty-four male Sprague-Dawley(SD) rats were randomly divided into control, pair-fed, doxoruhincin-induced nephrotic (nephrotic) and dexamethasone-treated nephrotic (des-treated ) rats. Serum GHB P, GHB P- 1 and liver GHR were measured by dextran-coated charcoal technique, gel filtration and radioreceptor assay respectively. Results (1) Serum GHBP and liver GHR were reduced in nephrotic and des-treated rats compared with control and pair-fed rats, but no significant difference was found between control and pair-fed rats or between nephrotic and des-treated rats. (2)Serum GHBP-1 was lower in pair-fed rats, even lower in nephrotic rats and lowest in des-treated rats than in control. (3) There was some significantly positive correlations between nose-tail length or weight and serum GHBP or liver GHR. Conclusion GH resistance, due to decreasd liver GHR, is an important cause of growth failure induced by secondary malnutrition and nephrosis itself Glucocorticoid therapy deteriorates growth failure by further decreased hepatic GHR.