Anti-bacterial activity of Achatina CRP and its mechanism of action.

The physiological role of C-reactive protein (CRP), the classical acute-phase protein, is not well documented, despite many reports on biological effects of CRP in vitro and in model systems in vivo. It has been suggested that CRP protects mice against lethal toxicity of bacterial infections by implementing immunological responses. In Achatina fulica CRP is a constitutive multifunctional protein in haemolymph and considered responsible for their survival in the environment for millions of years. The efficacy of Achatina CRP (ACRP) was tested against both Salmonella typhimurium and Bacillus subtilis infections in mice where endogenous CRP level is negligible even after inflammatory stimulus. Further, growth curves of the bacteria revealed that ACRP (50 µg/mL) is bacteriostatic against gram negative salmonellae and bactericidal against gram positive bacilli. ACRP induced energy crises in bacterial cells, inhibited key carbohydrate metabolic enzymes such as phosphofructokinase in glycolysis, isocitrate dehydrogenase in TCA cycle, isocitrate lyase in glyoxylate cycle and fructose-1,6-bisphosphatase in gluconeogenesis. ACRP disturbed the homeostasis of cellular redox potential as well as reduced glutathione status, which is accompanied by an enhanced rate of lipid peroxidation. Annexin V-Cy3/CFDA dual staining clearly showed ACRP induced apoptosis-like death in bacterial cell population. Moreover, immunoblot analyses also indicated apoptosis-like death in ACRP treated bacterial cells, where activation of poly (ADP-ribose) polymerase-1 (PARP) and caspase-3 was noteworthy. It is concluded that metabolic impairment by ACRP in bacterial cells is primarily due to generation of reactive oxygen species and ACRP induced anti-bacterial effect is mediated by metabolic impairment leading to apoptosis-like death in bacterial cells.

investigation of the anti-diabetic effects of an extract from Cladonia humilis

The effect of Cladonia humilis on glycaemic metabolism was researched in this studied. The blood glucose, insulin secretion and glycogen synthesis of the hyperglycemic mice induced by alloxan were analyzed respectively. The gluconeogenesis and the sugar tolerance of the normal mice were also analyzed in this paper. After the hyperglycemic mice were orally administrated with Cladonia humilis extract, the blood glucose was decreased [p<0.05], the level of insulin secretion and glycogen synthesis were elevated [p<0.05, p<0.01, respectively]. In addition, Cladonia humilis extract could inhibite the gluconeogenesis [p<0.01] and improve the sugar tolerance in normal control mice. These results maybe account for the causes of Cladonia humilis extract-induced significant decreases of the blood glucose in hyperglycemic mice

Metabolic changes induced by pre-administration of L-alanyl-glutamine and Omega-3 in Wistar rats subjected to sepsis / Alterações metabólicas induzidas pela pré-administração de L-alanil-glutamina e ômega-3 em ratos Wistar submetidos à sepse

PURPOSE: To evaluate the metabolic changes induced by pre-administration of L-alanyl-glutamine (L-Ala-Gln) and omega-3 (ω-3) in rats subjected to sepsis. METHODS: Eighteen male Wistar rats were randomized into three groups (n=6) and treated with saline (group Control-G-1), L-Ala-Gln (0.75 mg /kg , G-2) or ω-3 (0.2 g /kg, G-3 ) administered intravenously 3, 2 and 1 day and 30 minutes before induction of sepsis. Samples (blood, striated muscle and liver) were collected 48 hours after induction of sepsis, to measure the concentrations of metabolites (pyruvate, lactate, glucose and ketone bodies. RESULTS: There was a significant increase in muscle glycolysis and gluconeogenesis in the liver in rats treated with L-Ala-Gln and ω-3, compared to the control group, 48 hours after induction of sepsis. CONCLUSION: Pre-administration of L-Ala-Gln or ω-3 to rats subjected to sepsis resulted in similar metabolic changes, by rising glycolysis in peripheral tissues and stimulating hepatic gluconeogenesis and ketogenesis, resulting in increased energy supply to septic rats.

OBJETIVO: Avaliar as alterações metabólicas induzidas pela pré-administração de L-alanil-glutamina (L-Ala-Gln) e ômega-3 (ω-3) em ratos Wistar submetidos à sepse. MÉTODOS: Dezoito ratos machos Wistar, randomizados em três grupos iguais (n=6) e tratados com solução salina (grupo Controle-G-1), L-Ala-Gln (0,75mg/Kg) ou ω-3 (0,2g/Kg) por via endovenosa administrados 3, 2 e 1 dia e 30 minutos antes da indução do estado de sepse. Amostras (sangue, músculo estriado e fígado) foram coletadas 48 horas após indução da sepse, para dosagem das concentrações de metabólitos (piruvato, lactato, glicose e corpos cetônicos). RESULTADOS: Houve aumento significante da glicólise no músculo e da gliconeogênese no fígado nos ratos tratados com L-Ala-Gln e ω-3, comparados ao controle, 48 horas após a indução da sepse. CONCLUSÃO: A pré-administração de L-Ala-Gln ou ω-3 em ratos submetidos à sepse resultou em alterações metabólicas semelhantes, com aumento da glicólise nos tecidos periféricos e da gliconeogênese hepática e cetogênese, aumentando a oferta de energia disponível.

Alterations of epinephrine-induced gluconeogenesis in aging

The effects of glucagon and epinephrine on gluconeogenesis in young (4 month) and old (24 month) Fisher 344 rat hepatocytes were compared. In contrast to glucagon, which had a similar effect on gluconeogenesis in both young and old cells, epinephrine caused a smaller increase in gluconeogenesis in old rat hepatocytes than in young hepatocytes. beta2 adrenergic receptor (beta2-AR) expression slightly decreased in aged rat liver, and there were differences between young and old hepatocytes in their patterns of G protein coupled receptor kinases, which are involved in the activation of beta2-AR receptor signal desensitization. The major isoform of the kinase changed from GRK2 to GRK3 and the expression of beta-arrestin, which is recruited by the phosphorylated beta2-AR for internalization and degradation, increased in aged rat liver. GRK3 overexpression also decreased the glucose output from young rat hepatocytes. We conclude that an age-associated reduction in epinephrine-induced gluconeogenesis occurs through the epinephrine receptor desensitizing system.

Alterations of epinephrine-induced gluconeogenesis in aging

The effects of glucagon and epinephrine on gluconeogenesis in young (4 month) and old (24 month) Fisher 344 rat hepatocytes were compared. In contrast to glucagon, which had a similar effect on gluconeogenesis in both young and old cells, epinephrine caused a smaller increase in gluconeogenesis in old rat hepatocytes than in young hepatocytes. beta2 adrenergic receptor (beta2-AR) expression slightly decreased in aged rat liver, and there were differences between young and old hepatocytes in their patterns of G protein coupled receptor kinases, which are involved in the activation of beta2-AR receptor signal desensitization. The major isoform of the kinase changed from GRK2 to GRK3 and the expression of beta-arrestin, which is recruited by the phosphorylated beta2-AR for internalization and degradation, increased in aged rat liver. GRK3 overexpression also decreased the glucose output from young rat hepatocytes. We conclude that an age-associated reduction in epinephrine-induced gluconeogenesis occurs through the epinephrine receptor desensitizing system.

Adiponectin and thiazolidinedione targets CRTC2 to regulate hepatic gluconeogenesis

During fasting periods, hepatic glucose production is enhanced by glucagon to provide fuels for other organs. This process is mediated via cAMP-dependent induction of the CREB regulated transcriptional coactivator (CRTC) 2, a critical transcriptional activator for hepatic gluconeogenesis. We have previously shown that CRTC2 activity is regulated by AMP activated protein kinase (AMPK) family members. Here we show that adiponectin and thiazolidinedione directly regulate AMPK to modulate CRTC2 activity in hepatocytes. Adiponectin or thiazolidinedione lowered glucose production from primary hepatocytes. Treatment of both reagents reduced gluconeogenic gene expression as well as cAMP-mediated induction of CRE reporter, suggesting that these reagents directly affect CREB/CRTC2- dependent transcription. Furthermore, adiponectin or thiazolidinedione mediated repression of CRE activity is largely blunted by co-expression of phosphorylation defective mutant CRTC2, underscoring the importance of serine 171 residue of this factor. Taken together, we propose that adiponectin and thiazolidinedione promote the modulation of AMPK-dependent CRTC2 activity to influence hepatic gluconeogenesis.

The effect of phytic acid on the levels of blood glucose and some enzymes of carbohydrate and lipid metabolism / El Efecto del ácido fítico sobre los niveles de la glucosa en sangre y sobre algunas enzimas del metabolismo de carbohidratos y lípidos

In this study, six groups of rats were fed as follows: Groups 1 and 2 were fed formulated diets supplemented with zinc or without zinc respectively. Groups 3 and 4 were fed formulated diets supplemented with zinc plus phytic acid extracted from sweet potato (Ipomea batatas) or commercial phytic acid respectively. Groups 5 and 6 were fed formulated diets supplemented with phytic acid extract from sweet potato or commercial phytic acid respectively. The animals were fed for three weeks and then sacrificed The activities of key enzymes of carbohydrate and lipid metabolism as well as transaminases in the liver were determined. Blood glucose level was also assessed. Phytic acid extract consumption from sweet potato and commercial phytic acid plus zinc supplement lowered blood glucose levels. There was no significant change in the activity of 6-phosphogluconate dehydrogenase among the groups. Similarly, phytic acid supplementation showed no significant decrease in the activity of pyruvate kinase compared to the group fed formulated diets. There was a significant increase in the activity of glucose-6-phosphate dehydrogenase in the groups fed phytic extract from sweet potato compared to the other groups. The activities of malic enzyme and ATP-citrate lyase in this study were not significantly altered among the groups. There is a lowering of blood glucose levels which is desirable for diabetics who consume sweet potato diets. The changes in some of the hepatic metabolic enzymes are geared towards compensating for the decreased glycolytic responses

En este estudio, se alimentaron seis grupos de ratas de la forma que a continuación se describe. Los grupos 1 y 2 fueron alimentados con dietas formuladas con o sin suplemento de zinc respectivamente. Los grupos 3 y 4 fueron alimentados con dietas formuladas con suplemento de zinc más ácido fítico extraído del boniato (Ipomea batatas) o el ácido fítico comercial respectivamente. Los grupos 5 y 6 fueron alimentados con dietas formuladas con suplemento de extracto de ácido fítico del boniato o ácido fítico comercial respectivamente. Los animales fueron alimentados durante tres semanas y luego sacrificados. Se determinó la actividad de las enzimas claves del metabolismo de carbohidratos y lípidos, así como las transaminasas en el hígado. Asimismo se evaluó el nivel de glucosa en sangre. El consumo de extracto de ácido fítico del boniato y el ácido fítico comercial más el suplemento de zinc, diminuyeron los niveles de glucosa en sangre. No hubo cambios significativos en la actividad de la 6-fosfogluconato deshidrogenasa entre los grupos. De modo similar, la suplementación con ácido fítico no mostró una disminución significativa de la actividad de la piruvato kinasa en comparación con el grupo alimentado con dietas formuladas. Sin embargo, hubo un aumento significativo en la actividad de la glucosa-6-fosfato deshidrogenasa en los grupos alimentados con extracto fítico de boniato en comparación con los otros grupos. No hubo alteración significativa de las actividades de la enzima málica y la ATP-citrato liasa en este estudio. Hay una disminución de los niveles de glucosa en sangre, deseable para los diabéticos que consumen dietas de boniato. Los cambios en algunas de las enzimas metabólicas hepáticas están encaminados a compensar la disminución de las respuestas glicolíticas.

Rat liver responsiveness to gluconeogenic substrates during insulin-induced hypoglycemia

Hepatic responsiveness to gluconeogenic substrates during insulin-induced hypoglycemia was investigated. For this purpose, livers were perfused with a saturating concentration of 2 mM glycerol, 5 mM L-alanine or 5 mM L-glutamine as gluconeogenic substrates. All experiments were performed 1 h after an ip injection of saline (CN group) or 1 IU/kg of insulin (IN group). The IN group showed higher (P<0.05) hepatic glucose production from glycerol, L-alanine and L-glutamine and higher (P<0.05) production of L-lactate, pyruvate and urea from L-alanine and L-glutamine. In addition, ip injection of 100 mg/kg glycerol, L-alanine and L-glutamine promoted glucose recovery. The results indicate that the hepatic capacity to produce glucose from gluconeogenic precursors was increased during insulin-induced hypoglycemia.

Modulation of some gluconeogenic enzyme activities in diabetic rat liver and kidney: effect of antidiabetic compounds.

The effects of insulin, sodium orthovanadate and a hypoglycemic plant material, Trigonella foenum graecum (fenugreek) seed powder were studied on the activities of glucose-6-phosphatase and fructose-1,6-bisphosphatase in diabetic liver and kidney. The significantly increased activities of the two enzymes during diabetes in liver and kidney were found to be lowered to almost control values by the use of the antidiabetic compounds. Diabetic liver exhibited a much greater increase in the activities of the two enzymes than diabetic kidney. The highest percentage of reversal to normal values was seen using the combination of vanadate and Trigonella seed powder. The lowered rate of growth of the animals as well as the increased blood sugar were reversed almost to the control levels by the Trigonella seed powder and vanadate treatment. The inclusion of the Trigonella seed powder overcame the toxicity of vanadium encountered when it was given alone as insulin mimetic agent. Much lower levels of vanadate were needed when it was given in combination with Trigonella seed powder. Their combined effects were better at restoring the above parameters than those induced by insulin administration.

Gluconeogenesis and glycogenolysis in fluoride-treated rats.

Intraperitonial administration of 10 mg fluoride (NaF)/kg body weight resulted in hyperglycemia in rats. Role of gluconeogenesis and glycogenolysis in this hyperglycemic response was evaluated. Results of the study indicate that the fluoride induced hyperglycemia is mainly due to increased hepatic glycogenolysis.

Protective effective of vitamin E in kidney storage solution on renal tissue metabolism in rats.

OBJECTIVE: To determine whether inclusion of vitamin E into kidney storage solutions protects metabolism and tubular ultrastructure of stored rat kidney. METHODS: Rat kidneys were flush stored in Marshall's Citrate (MC) and MC + vitamin E (25% of LD 50 and 50% of LD 50) for 24 hours at 0 degrees C. After storage kidney slices were tested for gluconeogenesis and lactate dehydrogenase (LDH) activity, and examined for cellular ultrastructure. RESULTS: Kidneys stored in MC + vitamin E gave higher gluconeogenesis than those stored in MC alone (p < 0.001). Tubular ultrastructure was better preserved in the presence of Vitamin E. CONCLUSIONS: Vitamin E appears to protect the metabolism and ultrastructure of stored rat kidneys.

Hypoglycemic effects of Coccinia indica: inhibition of key gluconeogenic enzyme, glucose-6-phosphatase.

Coccinia indica (Family: Cucurbitaceae, locally known as telakucha) leaves were extracted with 95% ethanol. Following evaporation of the solvents, the residue was suspended in distilled water. When this suspension was fed orally to male normal-fed and 48-hr starved rats, the blood glucose was lowered 21% (P less than 0.01) in normal-fed and 24% (P less than 0.001) in 48-hr starved animals respectively. Starvation had induced a 3-fold increase in the activity of glucose-6-phosphatase and this activity was depressed 19% (P less than 0.05) by extract feeding while basal activity of the enzyme in normal-fed rats remained unaffected. Consistent with the depression of glucose-6-phosphatase, urea cycle enzyme arginase was also depressed 21% (P less than 0.001) and 12% (P less than 0.01) in the liver of 48 hr-starved and normal-fed animals respectively. Unlike glucose-6-phosphatase, starvation induced levels of gluconeogenic enzymes alanine aminotransferase and aspartate aminotransferase were not affected by Coccinia extract. These results suggest that the hypoglycemic effect of C. indica is partly due to the repression of the key gluconeogenic enzyme glucose-6-phosphatase.

The effect of the omission of perfusate orthophospahate on lactate gluconeogenesis and Pi exchange in the perfused fasted rat liver

En la estandardización de un método para la perfusión del hígado de la rata. Hems et al., observaron que al omitir el fosfato del medio tenía lugar una reducción de la neoglucogénesis a partir de lactado, en un 50%. Con el propósito de utilizar esta técnica para producir deplección aguda de fosfato en el hígado, se realizaron experimentos similares con un perfusado que sólo difería por contener aproximadamente el doble de eritrocitos humanos (20-22%). Los glóbulos rojos humanos usados habían sido envejecidos 4-5 semanas en condiciones de banco de sangre. Hems y colaboradores encontraron que en estas condiciones los hematíes pierden su poder glicolítico y mantienen su capacidad para transportar oxígeno. Con el fin de acentuar la depleción de Pi, los hígados de las ratas previamente mantenidas en ayunas por 24 h. fueron perfundidos con medio sin fosfato por 75 min. y luego transferidos a otro aparato de perfusión también privado de Pi en el cual se mantuvo al órgano por 120 min. adicionales. A los 15 min. de haber montado el hígado para la segunda perfusión 1 micronCI de Pi de alta actividad por ml, se añadió al medio y a los 15 min. se tomó la muestra cero, de allí en adelante se obtuvieron muestras adicionales cada 15 min. La omisión de fosfato del medio no redujo la gluconeogenesis a partir del lactado ni aún añadiendo glucagon para estimular ese proceso. En los experimentos de perfusión del hígado y en los blancos en los cuales se hizo circular el perfusado en ausencia del hígado, se observó que el valor inicial de Pi era alrededor de 50% del obtenido con el medio standard, lo que indica que la liberación de fosfato por los hematíes y por el hígado no permitió trabajar con el medio libre del anión. La hemólisis fue mínima y las muestras fueron esfriadas rápidamente para evitar desintegración de compuestos fosforados. Se observó también que los glóbulos rojos humanos envejecidos por 4-5 semanas no pierden su poder glicolítico. En la depleción parcial del fosfato obtenida en nuestros experimentos, el lactado y con mayor intensidad el lactado...

Inhibition of the glucagon induced incorporation of orthophosphate into the liver by gluconeogenic blockers

Hígados aislados de ratas alimentadas, fueron perfundidos con un medio preparado a partir de solución KRB a la cual se añadieron: seroalbúmina bovina, 3g/dl; glucosa, 90 mg/dl; ortofosfato para obtener una concentración en el plasma de 1 mg/dl; 18 por ciento de glóbulos rojos de rata lavados; pH, 7.40, fase gaseosa O2 95%-CO2 5%. Flujo 36 ml/min. Temperatura, 37-C. Volumen del perfusado 70 ml. 0,5 micronCi de 32P-ortofosfato por ml. fueron añadidos al perfusado diez minutos antes de montar el hígado: el tiempo, 15 minutos después de montar el órgano, se tomó como punto cero. En los experimentos en los cuales se emplearon los bloqueadores de la neoglucogénesis ( quinolinato 1,68 mM o aminoóxi-acetato 0.2 mM) éstos fueron añadidos al perfusado al tiempo 15 min. el glucagon, cuando fue administrado, se empleó en inyección continua entre 45 y 90 min. (20 microngm). Se tomaron muestras cada 15 minutos hasta 120 minutos, que se recogieron en tubos enfriados en hielo. Glucosa en el perfusado, Pi en el plasma, 32Pi en perfusado y actividad específica del Pi plasmático fueron los parámetros determinados. Se calcularon Deltas a partir de 45 min. Los valores de glucosa y de Pi plasmático se corrigieron a partir de blancos obtenidos, haciendo circular el perfusado en ausencia del hígado y los resultados se expresaron por 10g de hígado fresco