Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tumor necrosis factor (TNF), interleukin 1 (IL-1) and interleukin 6 (IL-6) are central mediators of the inflammatory response. We investigated the modulation of these cytokines by hormones in vitro. Murine adherent peritoneal exudate cells (PEC) were exposed to various concentrations of hormones followed by lipopolysaccharide (LPS, 10 micrograms/ml). TNF, IL-1 and IL-6 production were assessed by bioassays, enzyme-linked immunosorbent assays (ELISA) or Western blot, and specific RNA transcripts by Northern blot. Hydrocortisone in concentrations as low as 10 ng/ml had dramatic inhibitory effects on supernatant levels of TNF and IL-1 and on TNF, IL-1 and IL-6 transcript number. Supernatant levels of IL-6 were only slightly diminished by hydrocortisone. Adrenocorticotrophic hormone (ACTH) and insulin increased supernatant levels of TNF bioactivity in response to LPS, while each decreased available TNF-alpha gene transcripts. Thus TNF protein production was affected at a post-transcriptional level. ACTH and insulin increased supernatant levels of IL-6 produced in response to LPS without altering available transcripts. Corticotrophin-releasing factor (CRF), epinephrine and glucagon had no effect on supernatant levels of cytokine. Thus, physiological and pharmacological concentrations of hydrocortisone had dramatic inhibitory effects on the supernatant levels of TNF and IL-1, and on the number of available TNF, IL-1 and IL-6 transcripts in PEC exposed to LPS, but had minimal effects on supernatant levels of IL-6 bioactivity. This hydrocortisone action may be a specific negative feedback system for IL-1 and TNF, with relative sparing of IL-6.
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PMID:Hormonal regulation of inflammatory cell cytokine transcript and bioactivity production in response to endotoxin. 131 63

Several endocrine hormones which influence liver metabolism are known to increase in activity during the acute phase of injury or inflammation. We determined whether these hormones have the potential to influence acute-phase protein production in human and rat hepatoma cells. Catecholamines, glucagon, growth hormone, triiodothyronine, and cyclic nucleotides individually or in combination did not modulate the basal or the interleukin-1 (IL-1)-, IL-6-, and dexamethasone-stimulated levels of acute-phase plasma proteins. Insulin, however, was found to be a rapid, nonspecific, and dose-dependent inhibitor of the cytokine and glucocorticoid stimulation of acute-phase protein gene expression and to exert its effect at the transcriptional level. The insulin inhibition applied to all cytokines tested but to various degrees, depending upon the particular acute-phase gene. Insulin resulted in an early and prominent increase in the transcription of genes encoding the AP-1 components of JunA, JunB, and c-Fos, as has been observed for other growth factors. However, the effect of insulin on C/EBP beta was unexpected and paradoxical: while insulin completely inhibited the transcriptional activation of the C/EBP beta gene in cytokine- and dexamethasone-treated cells, the level of cytoplasmic C/EBP beta RNA was elevated. Quantitation of C/EBP beta mRNA by Northern (RNA) blot analysis and of C/EBP beta DNA binding activity by Southwestern (DNA-protein) blot analysis showed that insulin, when combined with cytokines and dexamethasone, stimulated both the mRNA and DNA binding activity by a factor of 1.6 compared with that of cells treated with cytokines and dexamethasone alone. Transient transfection of H-35 and HepG2 cells with a chloramphenicol acetyltransferase (CAT) gene expression vector containing the C/EBP beta response element also resulted in a 1.5-fold increase of C/EBP beta-mediated transcription in insulin-treated cells. Transfection of CAT gene constructs containing increasing lengths of heptaglobin gene 5' flanking sequences indicated that insulin inhibition of IL-6 stimulation required the presence of the region from -4100 to -1030. These results suggest that insulin has the potential to control the transcription of acute-phase genes by at least two separate mechanisms.
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PMID:Insulin is a prominent modulator of the cytokine-stimulated expression of acute-phase plasma protein genes. 137 89

Granulocyte/macrophage-colony stimulating factor (GM-CSF) is a regulatory cytokine important in the proliferative and functional activation of hematopoietic cells. It belongs to a family of 20 kDa or less acidic glycoprotein molecules found in a broad range of cellular sources. On the basis of the previously reported nucleotide-binding properties of interleukin-2 (IL-2), atrial natriuretic factor (ANF), and glucagon, the interaction of GM-CSF with nucleotides was investigated. Using radiolabeled 8-azidoadenosine-containing photoprobes of ATP ([gamma-32P]-8N3ATP) and Ap4A, the putative biological alarmone ([beta'-32P]-8N3Ap4A), we have identified a nucleotide binding site on recombinant murine GM-CSF (rmGM-CSF). Specificity of binding was demonstrated by saturation and competition experiments. Saturation of photoinsertion by [gamma-32P]-8N3ATP and [beta'-32P]-8N3Ap4A occurs with apparent Kd's of 10 and 0.7 microM, respectively. Using an immobilized Fe3+ affinity chromatography technique, developed specifically for the isolation of photolabeled peptides, a single radiolabeled peptide was isolated. It was identified as amino acids 5-14 near the N-terminus of GM-CSF. This peptide region has been shown in previous studies to be critical for biological activity. Also consistent with this observation is our finding that the photolabeled GM-CSF has lost most, if not all, of its biological activity, as determined by a cellular proliferation assay.
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PMID:Identification and characterization of a nucleotide binding site on recombinant murine granulocyte/macrophage-colony stimulating factor. 146 78

We have previously reported that the combination of IFN-gamma plus TNF-alpha is able to induce the de novo expression of HLA class II on human beta cells. In the present study, we have investigated the effect of these cytokines, alone or in combination, on the function and viability of human islet cells in vitro. Three hour insulin release was markedly reduced in human islet monolayer cultures after 4 days' exposure to 1000 U/ml of the combination TNF-alpha plus IFN-gamma (36.7 +/- 7.7, % of the control +/- SEM) or to TNF-alpha alone (49.5 +/- 7% of the control) while IFN-gamma had little effect. On direct inspection cell damage was clearly detected only in the cultures treated with TNF-alpha plus IFN-gamma in which staining by indirect immunofluorescence (IFL) for insulin revealed that the number of beta cells was also significantly reduced, thus suggesting a real cytotoxic effect of this cytokine combination. This effect was not beta cell specific since glucagon release and the number of alpha cells were also reduced in the cultures exposed to IFN-gamma plus TNF-alpha. 51Cr release experiments supported the cytoxicity of these cytokines to normal islet cells. There was a time course relationship between class II induction (2 days) and the cytotoxic effect of IFN-gamma plus TNF-alpha (4 days) on the same islet cells. In conclusion, these results indicate that the combination of IFN-gamma and TNF-alpha exerts a cytotoxic effect on human islet cells in vitro.
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PMID:Cytotoxic effect of IFN-gamma plus TNF-alpha on human islet cells. 190 37

Cytokine effects on permanent cell lines of transformed mouse pancreatic alpha- and beta-cells were compared. The beta-tumor cell 1 (beta TC1) line (from an adenoma created in transgenic mice expressing the SV40 large T-antigen oncogene under control of the rat insulin II promoter) produced insulin predominantly, although small quantities of intracellular glucagon (100:1 insulin to glucagon) were detectable by radioimmunoassay. The alpha TC1 line (from an adenoma created in transgenic mice expressing the SV40 large T-antigen oncogene under control of the rat preproglucagon promoter) produced not only glucagon but also considerable quantities of insulin (4:1 glucagon to insulin) and preproinsulin mRNA. We therefore cloned alpha TC1 cells and obtained 12 glucagon-producing clonal cell lines that did not produce levels of insulin detectable by radioimmunoassay. Analysis by Northern blotting of total RNA from two lines, alpha TC1 clones 6 and 9, confirmed the absence of preproinsulin mRNA. No somatostatin or pancreatic polypeptide was detected by immunohistochemical staining in alpha TC1 clones 6 or 9 or beta TC1 cells. Rat recombinant gamma-interferon (IFN-gamma; 5-250 U/ml) or mouse recombinant interleukin 1 (IL-1; 1-25 U/ml) individually inhibited DNA synthesis in beta TC1 cells after 3 days of treatment. The two cytokines in combination acted synergistically to further depress DNA synthesis and increase cytotoxicity. In contrast, alpha TC1 clone 9 cells were not sensitive to inhibition of DNA synthesis by each cytokine individually, although glucagon synthesis was inhibited. The combination of these cytokines caused marked inhibition of DNA and glucagon syntheses in alpha TC1 clone 9 cells. alpha TC1 clone 9 cells were somewhat more resistant to the cytotoxic action of the combined cytokines than were beta TC1 cells. Incubation with 50 U/ml IFN-gamma induced class II MHC molecules (I-Ab, I-Ad, and I-Ed) and enhanced the constitutive expression of class I molecules (H-2Kb and H-2Kd) on the cell surfaces of beta TC1, uncloned alpha TC1, and alpha TC1 clones 6 and 9. Thus, these cell lines are heterozygous for MHC alleles derived from both parental strains used in the construction of the transgenic mice [C57BL/6J (H-2b) and DBA/2J (H-2d)]. Class II gene transcription induced by IFN-gamma was confirmed in beta TC1 and alpha TC1 clone 9 cells by Northern blot analysis with A alpha-, A beta-, E alpha, and E beta-DNA probes.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Comparison of cytokine effects on mouse pancreatic alpha-cell and beta-cell lines. Viability, secretory function, and MHC antigen expression. 210 69

Interleukin-1 (IL-1), tumor necrosis factor (TNF), and interferon-gamma (IFN gamma) inhibit insulin release and may be cytotoxic to isolated rodent pancreatic islets. In this study we examined the effects of IL-1, TNF, and IFN gamma on the viability and hormone secretion of islets isolated from adult human pancreas and maintained in monolayer culture. IL-1 and TNF were cytotoxic to the islet cells (20-30% cell lysis) in a 51Cr release cytotoxicity assay, and IFN gamma had only small effects (less than 10% lysis). Combination of maximally cytotoxic concentrations of IL-1 (10 U/mL) and TNF (10(3) U/mL) produced an additive cytotoxic effect. IFN gamma (10(3) U/mL) acted synergistically with IL-1 and TNF, and the three cytokines added together produced maximal islet cell lysis (46.4 +/- 4.3%). Assay of insulin and glucagon in the islet monolayers revealed that IL-1, TNF, and IFN gamma inhibited both B- and A-cell secretory functions; however, only IL-1 and TNF produced permanent decreases in insulin and glucagon contents in the islet cultures. These findings indicate that IL-1 and TNF, as single agents, are cytotoxic to human islet cells, and that this cytotoxicity can be amplified by combining the cytokines and/or adding IFN gamma. However, the lack of specificity for B-cells in vitro suggests that additional factors might be operative in vivo for the cytokine products of macrophages and lymphocytes infiltrating islets to produce the B-cell-specific damage characteristic of type 1 diabetes.
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PMID:Cytotoxic effects of cytokines on human pancreatic islet cells in monolayer culture. 211 42

The in vivo alterations in organ-specific substrate processing and endogenous mediator production induced by endotoxin were investigated in healthy volunteers. An endotoxin bolus (20 U/kg) produced increased energy expenditure, hyperglycemia, hypoaminoacidemia, and an increase in circulating free fatty acids. These changes included increased peripheral lactate and free fatty acid output, along with increased peripheral uptake of glucose. Coordinately, there were increased splanchnic uptake of oxygen, lactate, amino acids, and free fatty acids, and increased splanchnic glucose output. There were no changes in circulating glucagon, or insulin and transient changes in epinephrine and cortisol were insufficient to explain the metabolic changes. Plasma cachectin levels peaked 90 min after the endotoxin infusion, and hepatic venous (HV) cachectin levels (peak 250 +/- 50 pg/ml) were consistently higher than arterial levels (peak 130 +/- 30 pg/ml, P less than 0.05 vs. HV). No interleukin 1 alpha or 1 beta was detected in the circulation. Circulating interleukin 6, measured by B.9 hybridoma proliferation, peaked 2 h after the endotoxin challenge (arterial, 16 +/- 2 U/ml; HV, 21 +/- 3 U/ml). The net cachectin efflux (approximately 7 micrograms) from the splanchnic organs demonstrates that these tissues are a major site for production of this cytokine. Hence, splanchnic tissues are likely influenced in a paracrine fashion by regional cachectin production and may also serve as a significant source for systemic appearance of this cytokine.
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PMID:The acute splanchnic and peripheral tissue metabolic response to endotoxin in humans. 234 17

We recently reported a potentiating effect of recombinant human interleukin-1 beta on glucose-stimulated insulin release from the isolated perfused pancreas. With the aim of determining whether the stimulatory effect of recombinant interleukin-1 beta on the B cell in the intact gland was modulated by varying the concentration, time of exposure to recombinant interleukin-1 beta or B-cell activity, and to elucidate a possible mechanism of action, we measured in the perfused rat pancreas the release of insulin, glucagon and/or prostaglandin E2 according to the following three different protocols: (1) perfusion with 20 ng/ml of recombinant interleukin-1 beta for 92 min at 5 and 20 mmol/l D-glucose (2) perfusion with varying concentrations of recombinant interleukin-1 beta ranging from 0.1 x 10(-3) ng/ml to 100 ng/ml at 5 and 20 mmol/l D-glucose (3) perfusion with 20 ng/ml of recombinant interleukin-1 beta at 5, 11 or 20 mmol/l D-glucose. Furthermore, in a separate set of experiments we examined the influence of the cytokine on the morphology of the endocrine pancreas. Interleukin-1 beta stimulated insulin secretion at 11 and 20 mmol/l D-glucose and potentiated first as well as second phase insulin release in a dose-dependent fashion, with decreasing effect at higher concentrations. Glucagon secretion was also stimulated by recombinant interleukin-1 beta, irrespective of increasing glucose (5, 11, 20 mmol/l) and insulin concentrations. The potentiating effect of recombinant interleukin-1 beta on insulin secretion was evident even after discontinued perfusion with the cytokine, suggesting a priming effect on B-cell function.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Functional and morphological effects of interleukin-1 beta on the perfused rat pancreas. 240 77

Intestinal mucosal atrophy, as induced by total parenteral nutrition (TPN) and/or prolonged bowel rest, is hypothesized to enhance bowel endotoxin (LPS) translocation and may alter host responses to infection. To examine the effect of TPN-induced bowel atrophy on the response to LPS, 12 healthy volunteers were randomized to receive either enteral feedings (ENT, n = 6) or seven days of TPN without oral intake (TPN, n = 6). Enteral or TPN feedings were terminated 12 hours before the study period when a constant dextrose infusion (50 mg/kg/hour) was initiated and continued throughout the subsequent study period. After placement of arterial, hepatic vein, and femoral vein catheters, metabolic parameters were determined before and for six hours after an intravenous E. coli LPS challenge (20 U/kg). Subsequent peak levels of arterial glucagon (ENT, 189 +/- 39 pg/mL; TPN, 428 +/- 48; p less than 0.01), arterial epinephrine (ENT, 236 +/- 52 pg/mL; TPN, 379 +/- 49; p less than 0.05) and hepatic venous cachectin/tumor necrosis factor (cachectin/TNF) (ENT, 250 +/- 56 pg/mL; TPN, 479 +/- 136; p less than 0.05) were significantly higher in the TPN group than in the ENT group. The extremity efflux of lactate (ENT, -16 +/- 4 micrograms/min-100cc tissue; TPN, -52 +/- 13; t = 2 hours; p less than 0.05) and of amino acids (ENT, -334 +/- 77 nmol/min-100cc tissue; TPN, -884 +/- 58; t = 4 hours; p less than 0.05) were higher in the TPN subjects after the endotoxin challenge. Circulating C-reactive Protein (CRP) levels measured 24 hours postendotoxin were also significantly higher in the TPN subjects (ENT, 1.7 +/- 0.2 mg/dL; TPN, 3.2 +/- 0.3; p less than 0.01). Hence the counter-regulatory hormone and splanchnic cytokine responses to LPS were enhanced after TPN and bowel rest. This is associated with a magnified acute-phase response, peripheral amino acid mobilization, and peripheral lactate production. Thus antecedent TPN may influence the metabolic alterations seen in infection and sepsis via both an exaggerated counter-regulatory hormone response as well as an enhanced systemic and splanchnic production of cytokines.
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PMID:Total parenteral nutrition and bowel rest modify the metabolic response to endotoxin in humans. 250 83

The effects of acute administration of either tumour necrosis factor-alpha (cachectin) (TNF) or interleukin-1-beta (IL-1), or of tumour growth (Walker-256 carcinosarcoma), on blood amino acid concentrations and tissue alpha-amino[1-14C]isobutyrate (AIB) uptake in virgin and lactating rats were compared. Both monokines decreased the blood concentrations of those amino acids (serine, glycine, alanine and proline) transported via the A system. Tumour growth decreased the blood concentrations of serine, proline and histidine, whereas the concentrations of glutamine and leucine were increased. IL-1 decreased the intestinal absorption of AIB in all groups studied; TNF or tumour growth had no effect. Tissue AIB uptake was increased (1.5-2.5-fold) in liver, whereas it was decreased in heart and skeletal muscle of the three treatment groups (except skeletal muscle of the IL-1-treated rats). Lactating rats had lower hepatic uptake of AIB compared with livers of virgin rats. IL-1 increased the hepatic uptake of AIB in lactating rats, but not to the values seen in virgin rats treated with IL-1; there was no effect of the cytokine on muscle or mammary-gland uptake. In adrenalectomized rats, the stimulatory effect of IL-1 on hepatic AIB uptake was diminished, whereas that of TNF still persisted. IL-1 caused a marked decrease of AIB uptake in muscle and heart of adrenalectomized rats, which was accompanied by an increase in the blood concentrations of branched-chain amino acids. These effects did not occur with TNF. It is concluded that the effects of the cytokines on tissue amino acid metabolism may depend on a differential endocrine response involving glucagon and/or glucocorticoids.
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PMID:Comparative effects of tumour necrosis factor-alpha (cachectin), interleukin-1-beta and tumour growth on amino acid metabolism in the rat in vivo. Absorption and tissue uptake of alpha-amino[1-14C]isobutyrate. 278 41


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