Insulin suppresses LPS-induced iNOS and COX-2 expression and NF-kappa B activation in alveolar macrophages

The development of septic shock is a common and frequently lethal consequence of gram-negative infection. Mediators released by lung macrophages activated by bacterial products such as lipopolysaccharide (LPS) contribute to shock symptoms. We have shown that insulin downregulates LPS-induced TNF production by alveolar macrophages (AMs). In the present study, we investigated the effect of insulin on the LPS-induced production of nitric oxide (NO) and prostaglandin (PG)-E(2), on the expression of inducible nitric oxide synthase ( iNOS) and cyclooxygenase (COX)-2, and on nuclear factor kappa B (NF-kappa B) activation in AMs. Resident AMs from male Wistar rats were stimulated with LPS (100 ng/mL) for 30 minutes. Insulin (1 mU/mL) was added 10 min before LPS. Enzymes expression, NF-kappa B p65 activation and inhibitor of kappa B (I-kappa B) a phosphorylation were assessed by immunobloting; NO by Griess reaction and PGE(2) by enzyme immunoassay (EIA). LPS induced in AMs the expression of iNOS and COX-2 proteins and production of NO and PGE(2), and, in parallel, NF-kappa B p65 activation and cytoplasmic I-kappa B alpha phosphorylation. Administration of insulin before LPS suppressed the expression of iNOS and COX-2, of NO and PGE(2) production and Nuclear NF-kappa B p65 activation. Insulin also prevented cytoplasmic I-kappa Ba phosphorylation. These results show that in AMs stimulated by LPS, insulin prevents nuclear translocation of NF-kappa B, possibly by blocking I-kappa Ba degradation, and supresses the production of NO and PGE(2), two molecules that contribute to septic shock. Copyright (C) 2008 S. Karger AG, Basel.

Amyloid beta-peptide activates nuclear factor-kappa B through an N-methyl-D-aspartate signaling pathway in cultured cerebellar cells

Amyloid P-peptide (A beta) likely causes functional alterations in neurons well prior to their death. Nuclear factor-kappa B (NF-kappa B), a transcription factor that is known to play important roles in cell survival and apoptosis, has been shown to be modulated by A beta in neurons and glia, but the mechanism is unknown. Because A beta has also been shown to enhance activation of N-methyl-D-aspartate (NMDA) receptors, we investigated the role of NMDA receptor-mediated intracellular signaling pathways in A beta-induced NF-kappa B activation in primary cultured rat cerebellar cells. Cells were treated with different concentrations of A beta 1-40 (1 or 2 mu M) for different periods (6, 12, or 24 hr). MK-801 (NMDA antagonist), manumycin A and FTase inhibitor 1 (farnesyltransferase inhibitors), PP1 (Src-family tyrosine kinase inhibitor), PD98059 [mitogen-activated protein kinase (MAPK) inhibitor], and LY294002 [phosphatidylinositol 3-kinase (PI3-k) inhibitor] were added 20 min before A beta treatment of the cells. A beta induced a time- and concentration-dependent activation of NF-kappa B (1 mu M, 12 hr); both p50/p65 and p50/p50 NF-kappa B dimers were involved. This activation was abolished by MK-801 and attenuated by manumycin A, FTase inhibitor 1, PP1, PD98059, and LY294002. AP at 1 mu M increased the expression of inhibitory protein I kappa B, brain-derived neurotrophic factor, inducible nitric oxide synthase, tumor necrosis factor-alpha, and interleukin-1 beta as shown by RTPCR assays. Collectively, these findings suggest that AP activates NF-kappa B by an NMDA-Src-Ras-like protein through MAPK and PI3-k pathways in cultured cerebellar cells. This pathway may mediate an adaptive, neuroprotective response to A beta. (c) 2007 Wiley-Liss, Inc.

INSULIN REGULATES CYTOKINES AND INTERCELLULAR ADHESION MOLECULE-1 GENE EXPRESSION THROUGH NUCLEAR FACTOR-kappa B ACTIVATION IN LPS-INDUCED ACUTE LUNG INJURY IN RATS

Diabetic patients have increased susceptibility to infection, which may be related to impaired inflammatory response observed in experimental models of diabetes, and restored by insulin treatment. The goal of this study was to investigate whether insulin regulates transcription of cytokines and intercellular adhesion molecule 1 (ICAM-1) via nuclear factor-kappa B (NF-kappa B) signaling pathway in Escherichia coli LIPS-induced lung inflammation. Diabetic male Wistar rats (alloxan, 42 mg/kg, iv., 10 days) and controls were instilled intratracheally with saline containing LPS (750 mu g/0.4 mL) or saline only. Some diabetic rats were given neutral protamine Hagedorn insulin (4 IU, s.c.) 2 h before LIPS. Analyses performed 6 h after LPS included: (a) lung and mesenteric lymph node IL-1 beta, TNF-alpha, IL-10, and ICAM-1 messenger RNA (mRNA) were quantified by real-time reverse transcriptase-polymerase chain reaction; (b) number of neutrophils in the bronchoalveolar lavage (BAL) fluid, and concentrations of IL-1 beta, TNF-alpha, and IL-10 in the BAL were determined by the enzyme-linked immunosorbent assay; and (c) activation of NF-kappa B p65 subunit and phosphorylation of I-kappa B alpha were quantified by Western blot analysis. Relative to controls, diabetic rats exhibited a reduction in lung and mesenteric lymph node IL-1 beta (40%), TNF-alpha (similar to 30%), and IL-10 (similar to 40%) mRNA levels and reduced concentrations of IL-1 beta (52%), TNF-alpha (62%), IL-10 (43%), and neutrophil counts (72%) in the BAL. Activation of NF-kappa B p65 subunit and phosphorylation of I-kappa B alpha were almost suppressed in diabetic rats. Treatment of diabetic rats with insulin completely restored mRNA and protein levels of these cytokines and potentiated lung ICAM-1 mRNA levels (30%) and number of neutrophils (72%) in the BAL. Activation of NF-kappa B p65 subunit and phosphorylation of I-kappa B alpha were partially restored by insulin treatment. In conclusion, data presented suggest that insulin regulates transcription of proinflammatory (IL-1 beta, TNF-alpha) and anti-inflammatory (IL-10) cytokines, and expression of ICAM-1 via the NF-kappa B signaling pathway.

DAILY VARIATION OF CONSTITUTIVELY ACTIVATED NUCLEAR FACTOR KAPPA B (NFKB) IN RAT PINEAL GLAND

In mammals, the production of melatonin by the pineal gland is mainly controlled by the suprachiasmatic nuclei (SCN), the master clock of the circadian system. We have previously shown that agents involved in inflammatory responses, such as cytokines and corticosterone, modulate pineal melatonin synthesis. The nuclear transcription factor NFKB, detected by our group in the rat pineal gland, modulates this effect. Here, we evaluated a putative constitutive role for the pineal gland NFKB pathway. Male rats were kept under 12 h: 12 h light-dark (LD) cycle or under constant darkness (DD) condition. Nuclear NFKB was quantified by electrophoretic mobility shift assay on pineal glands obtained from animals killed throughout the day at different times. Nuclear content of NFKB presented a daily rhythm only in LD-entrained animals. During the light phase, the amount of NFKB increased continuously, and a sharp drop occurred when lights were turned off. Animals maintained in a constant light environment until ZT 18 showed diurnal levels of nuclear NFKB at ZT15 and ZT18. Propranolol (20 mg/kg, i.p., ZT 11) treatment, which inhibits nocturnal sympathetic input, impaired nocturnal decrease of NFKB only at ZT18. A similar effect was observed in free-running animals, which secreted less nocturnal melatonin. Because melatonin reduces constitutive NFKB activation in cultured pineal glands, we propose that this indolamine regulates this transcription factor pathway in the rat pineal gland, but not at the LD transition. The controversial results regarding the inhibition of pineal function by constant light or blocking sympathetic neurotransmission are discussed according to the hypothesis that the prompt effect of lights-off is not mediated by noradrenaline, which otherwise contributes to maintaining low levels of nuclear NFKB at night. In summary, we report here a novel transcription factor in the pineal gland, which exhibits a constitutive rhythm dependent on environmental photic information. (Author correspondence: rpmarkus@usp.br)

Oxidative stress and inflammatory mediators contribute to endothelial dysfunction in high-fat diet-induced obesity in mice

Objective We investigated the effects of high-fat diet-induced obesity on vascular proinflammatory factors and oxidative stress on endothelium-dependent relaxation of the aorta. Methods Female Swiss mice were submitted to a high-fat diet for 16 weeks. At the end of the experimental period, we evaluated blood pressure, relaxation in response to acetylcholine in aortic rings in the absence and the presence of the superoxide anion scavenger, superoxide dismutase (SOD, 150 U/ml), and the nuclear factor (NF)-kappa B inhibitor, sodium salicylate (5 mmol/l). Aortic protein expression of endothelial nitric oxide synthase, Cu/Zn-SOD, NF-kappa B, I kappa B-alpha, and proinflammatory cytokines were also evaluated. Results Obese mice presented higher systolic and diastolic blood pressure than control mice (P<0.05). The relaxation of aortas to acetylcholine, but not to sodium nitroprusside, was significantly decreased in obese mice and was corrected by both SOD and sodium salicylate (P<0.05). The protein expression of endothelial nitric oxide synthase and Cu/Zn-SOD was significantly decreased in aorta from obese mice (P<0.05). Total p65 NF-kappa B subunit protein expression was not affected by obesity, but the protein expression of NF-kappa B inhibitor I kappa B-alpha was lower in aorta from obese mice (P<0.05). There were no significant differences in the interleukin (IL)-1 beta and IL-6 protein expression between groups. In contrast, the expression of TNF-alpha was significantly increased in aortas from obese mice. Conclusion Our resultssuggest that the reducedantioxidant defense and the local NF-kappa B pathway play an important role in the impairment of endothelium-dependent relaxation in aorta from obese mice. J Hypertens 28: 2111-2119 (C) 2010 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.

Essential role of nuclear factor-kappa B for NADPH oxidase activity in normal and anhildrotic ectodermal dysplasia leukocytes

This work investigated the functional role of nuclear factor-kappa B (NF-kappa B) in respiratory burst activity and in expression of the human phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase genes CYBB, CYBA, NCF1, and NCF2. U937 cells with a stably transfected repressor of NF-kappa B (IKB alpha-S32A/S36A) demonstrated significantly lower superoxide release and lower CYBB and NCF1 gene expression compared with control U937 cells. We further tested Epstein-Barr virus (EBV)-transformed B cells from patients with anhidrotic ectodermal dysplasia with immunodeficiency (EDA-ID), an inherited disorderof NF-kappa B function. Superoxide release and CYBB gene expression by EDA-ID cells were significantly decreased compared with healthy cells and similar to cells from patients with X-linked chronic granulomatous disease (X91 degrees CGD). NCF1 gene expression in EDA-ID S321 cells was decreased compared with healthy control cells and similar to that in autosomal recessive (A47 degrees) CGD cells. Gel shift assays demonstrated loss of recombinant human p50 binding to a NF-kappa B site 5` to the CYBB gene in U937 cells treated with NF-kappa B inhibitors, repressor-transfected U937 cells, and EDA-ID patients cells. Zymosan phagocytosis was not affected by transfection of U937 cells with the NF-kappa B repressor. These studies show that NF-kappa B is necessary for CYBB and NCF1 gene expression and activation of the phagocyte NADPH oxidase in this model system.

Differing effects of exogenous and endogenous hydrogen sulphide in carrageenan-induced knee joint synovitis in the rat

Background and purpose: Recent findings suggest that the noxious gas H(2)S is produced endogenously, and that physiological concentrations of H(2)S are able to modulate pain and inflammation in rodents. This study was undertaken to evaluate the ability of endogenous and exogenous H(2)S to modulate carrageenan-induced synovitis in the rat knee. Experimental approach: Synovitis was induced in Wistar rats by intra-articular injection of carrageenan into the knee joint. Sixty minutes prior to carrageenan injection, the rats were pretreated with indomethacin, an inhibitor of H(2)S formation (dl-propargylglycine) or an H(2)S donor [Lawesson`s reagent (LR)]. Key results: Injection of carrageenan evoked knee inflammation, pain as characterized by impaired gait, secondary tactile allodynia of the ipsilateral hindpaw, joint swelling, histological changes, inflammatory cell infiltration, increased synovial myeloperoxidase, protein nitrotyrosine residues, inducible NOS (iNOS) activity and NO production. Pretreatment with LR or indomethacin significantly attenuated the pain responses, and all the inflammatory and biochemical changes, except for the increased iNOS activity, NO production and 3-NT. Propargylglycine pretreatment potentiated synovial iNOS activity (and NO production), and enhanced macrophage infiltration, but had no effect on other inflammatory parameters. Conclusions and implications: Whereas exogenous H(2)S delivered to the knee joint can produce a significant anti-inflammatory and anti-nociceptive effect, locally produced H(2)S exerts little immunomodulatory effect. These data further support the development and use of H(2)S donors as potential alternatives (or complementary therapies) to the available anti-inflammatory compounds used for treatment of joint inflammation or relief of its symptoms.

Anti-inflammatory effect of atorvastatin ameliorates insulin resistance in monosodium glutamate-treated obese mice

Considering that inflammation contributes to obesity-induced insulin resistance and that statins have been reported to have other effects beyond cholesterol lowering, the present study aimed to it whether atorvastatin treatment has anti-inflammatory action in white adipose tissue of obese mice, consequently improving insulin sensitivity. Insulin sensitivity in vivo (by insulin tolerance test); metabolic-hormonal profile; plasma tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and adiponectin; adipose tissue immunohistochemistry; glucose transporter (GLUT) 4; adiponectin; INF-alpha; IL-1 beta; and IL-6 gene expression; and I kappa B kinase (IKK)-alpha/beta activity were assessed in 23-week-old monosodium glutamate induced obese mice untreated or treated with atorvastatin for 4 weeks. Insulin-resistant obese mice had increased plasma triglyceride, insulin, TNF-alpha, and IL-6 plasma levels. Adipose tissue of obese animals showed increased macrophage infiltration, IKK-alpha (42%, P < .05) and IKK-beta (73%, P < .05) phosphorylation, and INF-alpha and IL-6 messenger RNA (mRNA) (similar to 15%, P < .05) levels, and decreased GLUT4 mRNA and protein (30%, P < .05) levels. Atorvastatin treatment lowered cholesterol, triglyceride, insulin, INF-alpha, and IL-6 plasma levels, and restored whole-body insulin sensitivity. In adipose tissue, atorvastatin decreased macrophage in and normalized IKK-alpha/beta phosphorylation; INF-alpha, IL-6, and GLUT4 mRNA; and GLUT4 protein to control levels. The present findings demonstrate that atorvastatin has anti-inflammatory effects on adipose tissue of obese mice, which may be important to its local and whole-body insulin-sensitization effects. (C) 2010 Published by Elsevier Inc.

Gene expression profiling reveals molecular marker candidates of laryngeal squamous cell carcinoma

Laryngeal squamous cell carcinoma is very common in head and neck cancer, with high mortality rates and poor prognosis. In this study, we compared expression profiles of clinical samples from 13 larynx tumors and 10 non-neoplastic larynx tissues using a custom-built cDNA microarray containing 331 probes for 284 genes previously identified by informatics analysis of EST databases as markers of head and neck tumors. Thirty-five genes showed statistically significant differences (SNR >= 11.01, p <= 0.001) in the expression between tumor and non-tumor larynx tissue samples. Functional annotation indicated that these genes are involved in cellular processes relevant to the cancer phenotype, such as apoptosis, cell cycle, DNA repair, proteolysis, protease inhibition, signal transduction and transcriptional regulation. Six of the identified transcripts map to intronic regions of protein-coding genes and may comprise non-annotated exons or as yet uncharacterized long ncRNAs with a regulatory role in the gene expression program of larynx tissue. The differential expression of 10 of these genes (ADCY6, AES, AL2SCR3, CRR9, CSTB, DUSP1, MAP3K5, PLAT, UBL1 and ZNF706) was independently confirmed by quantitative real-time RT-PCR. Among these, the CSTB gene product has cysteine protease inhibitor activity that has been associated with an antimetastatic function. Interestingly, CSTB showed a low expression in the tumor samples analyzed (p<0.0001). The set of genes identified here contribute to a better understanding of the molecular basis of larynx cancer, and provide candidate markers for improving diagnosis, prognosis and treatment of this carcinoma.

Sympathetic outflow activates the venom gland of the snake Bothrops jararaca by regulating the activation of transcription factors and the synthesis of venom gland proteins

The venom gland of viperid snakes has a central lumen where the venom produced by secretory cells is stored. When the venom is lost from the gland, the secretory cells are activated and new venom is produced. The production of new venom is triggered by the action of noradrenaline on both alpha(1)- and beta-adrenoceptors in the venom gland. In this study, we show that venom removal leads to the activation of transcription factors NF kappa B and AP-1 in the venom gland. In dispersed secretory cells, noradrenaline activated both NF kappa B and AP-1. Activation of NF kappa B and AP-1 depended on phospholipase C and protein kinase A. Activation of NF kappa B also depended on protein kinase C. Isoprenaline activated both NF kappa B and AP-1, and phenylephrine activated NF kappa B and later AP-1. We also show that the protein composition of the venom gland changes during the venom production cycle. Striking changes occurred 4 and 7 days after venom removal in female and male snakes, respectively. Reserpine blocks this change, and the administration of alpha(1)- and beta-adrenoceptor agonists to reserpine-treated snakes largely restores the protein composition of the venom gland. However, the protein composition of the venom from reserpinized snakes treated with alpha(1)- or beta-adrenoceptor agonists appears normal, judging from SDS-PAGE electrophoresis. A sexual dimorphism in activating transcription factors and activating venom gland was observed. Our data suggest that the release of noradrenaline after biting is necessary to activate the venom gland by regulating the activation of transcription factors and consequently regulating the synthesis of proteins in the venom gland for venom production.

Melatonin inhibits LPS-induced NO production in rat endothelial cells

Endothelial cells produce NO by activation of constitutive nitric oxide synthase (NOS) and transcription of inducible NOS (iNOS). We have previously shown that melatonin, in the nanomolar range, inhibits activation of constitutive NOS, and in the present paper, we evaluated whether it could interfere with the expression of iNOS, which is activated by lipopolysaccharide (LPS), a major component of gram-negative bacteria cell walls. Primary cultures of rat endothelial cells were loaded with fluorescent probe for NO detection. Nuclear factor kappa B (NF-kappa B) translocation in endothelial cells elicited by LPS was measured by electromobility shift assay, and the vasodilation of aortic rings was accessed by recording isometric contraction. Melatonin in a micromolar but not in a nanomolar range inhibits the NO production induced by LPS. This effect is not dependent on the activation of G protein-coupled melatonin receptors. The nuclear NF-kappa B translocation is a process necessary for iNOS transcription, and melatonin also inhibits its translocation. LPS induced vasodilation only in endothelium-intact aortic rings, and melatonin (10 mu m) inhibits the vasodilation. Here, we show that concentrations compatible with nocturnal melatonin surge (nm) did not interfere with the activity of iNOS. Considering that micromolar melatonin concentrations could be locally achieved through production by activated immune competent cells, extra-pineal melatonin could have a protective effect against tissue injury. We propose that melatonin blocked the LPS-induced vasodilation by inhibiting the NF-kappa B pathway. Finally, we propose that the effect of melatonin on vascular reactivity is one of the mechanisms that underlies the protective effect of this indolamine against LPS.

Effects of short chain fatty acids on effector mechanisms of neutrophils

Short chain fatty acids (SCFAs) are metabolic by products of anerobic bacteria fermentation. These fatty acids, despite being an important fuel for colonocytes, are also modulators of leukocyte function. The aim of this study was to evaluate the effects of SCFAs (acetate, propionate, and butyrate) on function of neutrophils, and the possible mechanisms involved. Neutrophils obtained from rats by intraperitoneal lavage 4 h after injection of oyster glycogen solution (1%) were treated with non toxic concentrations of the fatty acids. After that, the following measurements were performed: phagocytosis and destruction of Candida albicans, production of ROS (O(2)(center dot-), H(2)O(2), and HOCl) and degranulation. Gene expression (p47(phox) and p22(phox)) and protein phosphorylation (p47(phox)) were analyzed by real time reverse transcriptase chain reaction (RT-PCR) and Western blotting, respectively. Butyrate inhibited phagocytosis and killing of C. albicans. This SCFA also had an inhibitory effect on production of O(2)(center dot-), H(2)O(2), and HOCI by neutrophils stimulated with PMA or fMLP. This effect of butyrate was not caused by modulation of expression of NADPH oxidase subunits (p47(phox) and p22(phox)) but it was in part due to reduced levels of p47(phox) phosphorylation and an increase in the concentration of cyclic AMP. Acetate increased the production of O(2)(center dot-) and H(2)O(2), in the absence of stimuli but had no effect on phagocytosis and killing of C. albicans. Propionate had no effect on the parameters studied. These results suggest that butyrate can modulate neutrophil function, and thus could be important in inflammatory neutrophil-associated diseases. Copyright (C) 2008 John Wiley & Sons, Ltd.

Insulin resistance of pregnancy involves estrogen-induced repression of muscle GLUT4

Pregnancy is accompanied by hyperestrogenism, however, the role of estrogens in the gestational-induced insulin resistance is unknown. Skeletal muscle plays a fundamental role in this resistance, where GLUT4 regulates glucose uptake. We investigated: (1) effects of oophorectomy and estradiol (E2) on insulin sensitivity and GLUT4 expression. E2 (similar to 200 nM) for 7 days decreased sensitivity, reducing similar to 30% GLUT4 mRNA and protein (P< 0.05) and plasma membrane expression in muscle; (2) the expression of ER alpha and ER beta in L6 myotubes, showing that both coexpress in the same nucleus; (3) effects of E2 on GLUT4 in L6, showing a time- and dose-dependent response. High concentration (100 nM) for 6 days reduced similar to 25% GLUT4 mRNA and protein (P < 0.05). Concluding, E2 regulates GLUT4 in muscle, and at high concentrations, such as in pregnancy, reduces GLUT4 expression and, in vivo, decreases insulin sensitivity. Thus, hyperestrogenism may be involved in the pregnancy-induced insulin resistance and/or gestational diabetes. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

Involvement of Phosphatidylinositol-3 Kinase/AKT/PKC zeta/lambda Pathway in the Effect of Palmitate on Glucose-Induced Insulin Secretion

Objectives: In the present study, a novel pathway by which palmilate potentiates glucose-induced insulin secretion by pancreatic beta cells was investigated. Methods: Groups of freshly isolated islets were incubated in 10 mM glucose with palmitate, LY294002, wortmannin, and fumonism B I for measurement of insulin secretion by radioimmunoassay (RIA). Also, phosphorylation and content of AKT and PKC proteins were evaluated by immunoblotting. Results: Glucose plus palmitate and glucose plus LY294002 or wortmannin (PI3K inhibitors) increased glucose-induced insulin secretion by isolated pancreatic islets. Glucose at 10 mM induced AKT and PKC zeta/lambda phosphorylation. Palmitate (0.1 mM) abolished glucose stimulation of AKT and PKC zeta/lambda phosphorylation possibly through PI3K inhibition because both LY294002 (50 mu M) and wortmannin (100 nM) caused the same effect. The inhibitory effect of palmitate on glucose-induced AKT and PKC zeta/lambda phosphorylation and the stimulatory effect of palmitate on glucose-induced insulin secretion were not observed in the presence of fumonisin B1, all inhibitor of ceramide synthesis. Conclusions: These findings support the proposition that palmilate increases insulin release in the presence of 10 mM glucose by inhibiting PI3K activity through a mechanism that involves ceramide synthesis.

Glimepiride as insulin sensitizer: increased liver and muscle responses to insulin

Aim: Glimepiride, a low-potency insulin secretagogue, is as efficient on glycaemic control as other sulphonylureas, suggesting an additional insulin-sensitizer role. The aim of the present study was to confirm the insulin-sensitizer role of glimepiride and to show extra-pancreatic effects of the drug. Methods: Three-month-old monosodium glutamate (MSG)-induced obese insulin-resistant rats were treated (OG) or not treated (O) with glimepiride for 4 weeks and compared with age-matched non-obese rats (C). Insulin sensitivity in whole body, glucose transporter 4 (GLUT4) protein content, glucose uptake and glycogen synthesis in oxidative skeletal muscle and phospho-glycogen synthase kinase (p-GSK3) and glycogen content in liver were analysed. Results: Insulin sensitivity, analysed by the insulin tolerance test, was 30% lower in O than in C rats (p < 0.05), and OG rats recovered this parameter (p < 0.05). In oxidative muscle, glimepiride increased the GLUT4 protein content (50%, p < 0.001) and recovered the obesity-induced reduction (similar to 20%) of the in vitro insulin-stimulated glucose uptake and incorporation into glycogen. In liver, glimepiride increased p-GSK3 (p < 0.01) and glycogen (p < 0.05) contents. Conclusion: The increased GLUT4 protein expression and glucose utilization in oxidative muscle and the increased insulin sensitivity and glycogen storage in liver evidence the insulin-sensitizer effect of glimepiride, which must be important to enable the glimepiride drug to promote an efficient glycaemic control.