Increased Glycogen Levels Research Articles

Physiological Effect of Gentle Stroking in Lambs.

The aim of the study was to determine changes in physiological indicators in lambs subjected to gentle stroking. The study included 40 three-week-old lambs (20 females of the synthetic prolific-meat (BCP) line and 20 females of the Świniarka (SW) breed). The animals were assigned to two control groups (n = 20) and two experimental groups (n = 20). Lambs from the experimental groups received treatment. Analyses consisted of determining the following parameters: heart rate (HR), saturation (S) and biochemical analysis. In the groups of sheep subjected to gentle massage, the analyses revealed a significant increase in the levels of cortisol, CAT, GST, GPx, among others, and a significant decrease in the levels of total protein, SOD, TAC, uric acid and Na+. At the same time, indicators of reduced stress levels were revealed, i.e., a significant increase in glycogen levels and a significant decrease in glucose and HR values. These results suggest that the introduction of gentle touch can induce positive states in lambs, and that the stress response may be transient and adaptive. Nevertheless, it is important to note that these interactions can be a source of stress, even if the behavioral response does not necessarily indicate stress.

Oyster (Ostrea Plicatula Gmelin) Peptides Improve Exercise Endurance Capacity via Activating AMPK and HO-1

Objective Previous studies have shown that oyster peptides (OPs) have antioxidant and anti-fatigue activities. This study aimed to investigate the effects of OPs on swimming endurance in mice and the underlying mechanisms. Methods The mice were subjected to gavage with OPs and subjected to exercise training. After 14 days, various biochemical indicators in the blood and gastrocnemius muscle of mice were assessed, and real-time PCR was utilized to detect the level of signal pathway regulation by OPs in the gastrocnemius muscle. Molecular docking technology was employed to observe the potential active components in OPs that regulate signal pathways. Results In this study, OPs supplementation combined with and without exercise significantly extended swimming time compared to the sedentary group. OPs supplementation with exercise also increased glycogen levels and decreased blood urea nitrogen, lactate dehydrogenase, and lactic acid levels. Additionally, mice in the exercise with OPs group exhibited higher activities of antioxidant enzymes. OPs can upregulate metabolic regulatory factors such as AMP-activated protein kinase, peroxisome proliferator-activated receptor gamma coactivator-1 alpha, peroxisome proliferator-activated receptor delta, and glucose transporter 4, thereby increasing energy supply during exercise. Additionally, OPs enhances the expression of heme oxygenase 1 and superoxide dismutase 2, thereby reducing oxidative stress during physical activity. Molecular docking analyses revealed that peptides found in OPs formed hydrogen bonds with AMPK and HO-1, indicating that they can exert bioactivity by activating target proteins such as AMPK and HO-1. Conclusions OPs supplementation improved energy reserves, modulated energy metabolism pathways, and coordinated antioxidative stress responses, ultimately enhancing swimming endurance. These findings suggest that OPs have the potential to improve exercise levels by promoting metabolism and improving energy utilization efficiency.

1-Deoxynojirimycin Mitigates Glycogen and Carbohydrate Metabolic Enzyme Alterations in High Glucose-Induced Diabetic Tilapia: Implications for Therapeutic Intervention

This study investigated the effects of 1- deoxynojirimycin (DNJ) on blood glucose levels, body weight changes, glycogen levels, and carbohydrate marker enzyme activity in a high glucose-induced experimental diabetic tilapia model. We utilized spectrophotometry assay methods to achieve this objective. DNJ treatment significantly reduced blood glucose and mitigated body weight loss compared to the diabetic control group. Furthermore, DNJ treatment increased glycogen levels in liver and muscle tissues, suggesting its potential to enhance glycogen synthesis or reduce glycogen breakdown. DNJ treatment also modulated the activity of carbohydrate marker enzymes, indicating its possible inhibitory effect on enzymes involved in carbohydrate absorption and breakdown, which in turn may improve glucose homeostasis and control. The results of this study highlight DNJ's potential as a therapeutic agent for diseases associated with glycogen metabolism and glucose homeostasis, as well as its ability to influence body weight changes in diabetic conditions. Our findings contribute to the growing body of research on DNJ as a potential therapeutic agent for illnesses linked to glycogen and underscore its therapeutic potential for future treatments targeting glucose metabolism, glycemic control, and weight management.

The combination of quercetin and leucine synergistically improves grip strength by attenuating muscle atrophy by multiple mechanisms in mice exposed to cisplatin.

Both quercetin and leucine have been shown to exert moderately beneficial effects in preventing muscle atrophy induced by cancers or chemotherapy. However, the combined effects of quercetin and leucine, as well as the possible underlying mechanisms against cisplatin (CDDP)-induced muscle atrophy and cancer-related fatigue (CRF) remain unclear. To investigate the issues, male BALB/c mice were randomly assigned to the following groups for 9 weeks: Control, CDDP (3 mg/kg/week), CDDP+Q (quercetin 200 mg/kg/day administrated by gavage), CDDP+LL (a diet containing 0.8% leucine), CDDP+Q+LL, CDDP+HL (a diet containing 1.6% leucine), and CDDP+Q+HL. The results showed that quercetin in combination with LL or HL synergistically or additively attenuated CDDP-induced decreases in maximum grip strength, fat and muscle mass, muscle fiber size and MyHC level in muscle tissues. However, the combined effects on locomotor activity were less than additive. The combined treatments decreased the activation of the Akt/FoxO1/atrogin-1/MuRF1 signaling pathway (associated with muscle protein degradation), increased the activation of the mTOR and E2F-1 signaling pathways (associated with muscle protein synthesis and cell cycle/growth, respectively). The combined effects on signaling molecules present in muscle tissues were only additive or less. In addition, only Q+HL significantly increased glycogen levels compared to the CDDP group, while the combined treatments considerably decreased CDDP-induced proinflammatory cytokine and MCP-1 levels in the triceps muscle. Using tumor-bearing mice, we demonstrated that the combined treatments did not decrease the anticancer effect of CDDP. In conclusion, this study suggests that the combination of quercetin and leucine enhanced the suppressed effects on CDDP-induced muscle weakness and CRF through downregulating muscle atrophy and upregulating the glycogen level in muscle tissues without compromising the anticancer effect of CDDP. Multiple mechanisms, including regulation of several signaling pathways and decrease in proinflammatory mediator levels in muscles may contributed to the enhanced protective effect of the combined treatments on muscle atrophy.

Platelet glycogenolysis is important for energy production and function

Although the presence of glycogen in platelets was established in the 1960s, its importance to specific functions (i.e., activation, secretion, aggregation, and clot contraction) remains unclear. Patients with glycogen storage disease often present with increased bleeding and glycogen phosphorylase (GP) inhibitors, when used as treatments for diabetes, induce bleeding in preclinical studies suggesting some role for this form of glucose in hemostasis. In the present work, we examined how glycogen mobilization affects platelet function using GP inhibitors (CP316819 and CP91149) and a battery of ex vivo assays. Blocking GP activity increased glycogen levels in resting and thrombin-activated platelets and inhibited platelet secretion and clot contraction, with minimal effects on aggregation. Seahorse energy flux analysis and metabolite supplementation experiments suggested that glycogen is an important metabolic fuel whose role is affected by platelet activation and the availability of external glucose and other metabolic fuels. Our data shed light on the bleeding diathesis in glycogen storage disease patients and offer insights into the potential effects of hyperglycemia on platelets.

Skeletal muscle growth activity of Olive Flounder (Paralichthys olivaceus) meat digest

Mammalian skeletal muscles play a pivotal role in the body and are mainly responsible for movement, metabolism, and energy consumption. Proteins that regulate muscle hypertrophy and atrophy are involved in muscle growth. A sufficient intake of dietary protein is essential for maintaining good health during normal growth and aging. Olive flounder (Paralichthys olivaceus) is one of the most common flatfish species in the South Korean aquaculture industry, and its consumption has been associated with various health benefits, such as a lower risk of cancers, heart failure, and chronic diseases. The present study attempted to determine the effect on muscle growth of flounder meat digest prepared using an in vitro gastric model. The capacity of digested flounder meat to enhance muscle growth was evaluated by examining glycogen levels and creatine kinase activity during muscle differentiation. The expression of muscle growth regulatory proteins was also evaluated. Treatment with flounder meat digest significantly and dose-dependently increased glycogen levels and creatine kinase activity in C2C12 cells. Moreover, proteins that are responsible for muscle hypertrophy and atrophy were significantly upregulated and downregulated, respectively. These results were confirmed using western blotting and immunofluorescence assays. The results of this study suggest that digested flounder meat has great potential for skeletal muscle growth and can be used as a functional food ingredient.

Chemical Triggering Cyanobacterial Glycogen Accumulation: Methyl Viologen Treatment Increases Synechocystis sp. PCC 6803 Glycogen Storage by Enhancing Levels of Gene Transcript and Substrates in Glycogen Synthesis.

Two-stage cultivation is effective for glycogen production by cyanobacteria. Cells were first grown under adequate nitrate supply (BG11) to increase biomass and subsequently transferred to nitrogen deprivation (-N) to stimulate glycogen accumulation. However, the two-stage method is time-consuming and requires extensive energy. Thus, one-stage cultivation that enables both cell growth and glycogen accumulation is advantageous. Such one-stage method could be achieved using a chemical triggering glycogen storage. However, there is a limited study on such chemicals. Here, nine compounds previously reported to affect cyanobacterial cellular functions were examined in Synechocystis sp. PCC 6803. 2-Phenylethanol, phenoxyethanol, 3-(3,4-dichlorophenyl)-1,1-dimethylurea and methyl viologen can stimulate glycogen accumulation. The oxidative stress agent, methyl viologen significantly increased glycogen levels up to 57% and 69% [w/w dry weight (DW)] under BG11 and -N cultivation, respectively. One-stage cultivation where methyl viologen was directly added to the pre-grown culture enhanced glycogen storage to 53% (w/w DW), compared to the 10% (w/w DW) glycogen level of the control cells without methyl viologen. Methyl viologen treatment reduced the contents of total proteins (including phycobiliproteins) but caused increased transcript levels of glycogen synthetic genes and elevated levels of metabolite substrates for glycogen synthesis. Metabolomic results suggested that upon methyl viologen treatment, proteins degraded to amino acids, some of which could be used as a carbon source for glycogen synthesis. Results of oxygen evolution and metabolomic analysis suggested that photosynthesis and carbon fixation were not completely inhibited upon methyl viologen treatment, and these two processes may partially generate upstream metabolites required for glycogen synthesis.

Effect of estradiol and IGF1 on glycogen synthesis in bovine uterine epithelial cells.

Glucose is an important nutrient for the endometrium and embryo during pregnancy. This study shows that estradiol (E2)/IGF1 signaling stimulates glycogen synthesis in the uterine epithelium of cows, which could provide glucose when needed. Glycogen storage in the uterine epithelium peaks near estrus and is a potential source of glucose for the endometrium and embryos. However, the hormonal regulation of glycogen synthesis in the uterine epithelium is poorly understood. Our objective was to evaluate the effect of E2 and insulin-like growth factor 1 (IGF1) on glycogenesis in immortalized bovine uterine epithelial (BUTE) cells. Treatment of BUTE cells with E2 (0.1-10 nM) did not increase glycogen levels. However, treatment of BUTE cells with IGF1 (50 or 100 ng/mL) resulted in a >2-fold increase in glycogen. To determine if the uterine stroma produced IGF1 in response to E2, bovine uterine fibroblasts were treated with E2, which increased IGF1 levels. Immunohistochemistry showed higher levels of IGF1 in the stroma on day 1 than on day 11, which coincides with higher glycogen levels in the uterine epithelium. Western blots revealed that IGF1 treatment increased the levels of phospho-AKT, phospho-GSKβ, hexokinase 1, and glycogen synthase in BUTE cells. Metabolomic (GC-MS) analysis showed that IGF1 increased 3-phosphoglycerate and lactate, potentially indicative of increased flux through glycolysis. We also found higher levels of N-acetyl-glucosamine and protein glycosylation after IGF1 treatment, indicating increased hexosamine biosynthetic pathway activity. In conclusion, IGF1 is produced by uterine fibroblasts due to E2, and IGF1 increases glucose metabolism and glycogenesis in uterine epithelial cells. Glycogen stored in the uterine epithelium due to E2/IGF1 signaling at estrus could provide glucose to the endometrium or be secreted into the uterine lumen as a component of histotroph.

Endometrial glycogen metabolism during early pregnancy in mice.

Glucose is critical during early pregnancy. The uterus can store glucose as glycogen but uterine glycogen metabolism is poorly understood. This study analyzed glycogen storage and localization of glycogen metabolizing enzymes from proestrus until implantation in the murine uterus. Quantification of diastase-labile periodic acid-Schiff (PAS) staining showed glycogen in the glandular epithelium decreased 71.4% at 1.5 days postcoitum (DPC) and 62.13% at DPC 3.5 compared to proestrus. In the luminal epithelium, glycogen was the highest at proestrus, decreased 46.2% at DPC 1.5and 63.2% at DPC 3.5. Immunostaining showed that before implantation, glycogen metabolizing enzymes were primarily localized to the glandular and luminal epithelium. Stromal glycogen was low from proestrus to DPC 3.5. However, at the DPC 5.5 implantation sites, stromal glycogen levels increased sevenfold. Similarly, artificial decidualization resulted in a fivefold increase in glycogen levels. In both models, decidualization increased expression of glycogen synthase as determine by immunohistochemistry and western blot. In conclusion, glycogen levels decreased in the uterine epithelium before implantation, indicating that it could be used to support preimplantation embryos. Decidualization resulted in a dramatic increase in stromal glycogen levels, suggesting it may have an important, but yet undefined, role in pregnancy.

Abstract P148: Glycogen phosphorylase and synthase inhibitors: Novel therapeutic approaches in anaplastic thyroid cancer

Abstract Thyroid cancer (TC) is the most common endocrine cancer. Effective treatment options for papillary (PTC) and follicular (FTC) thyroid cancers afford positive patient prognoses. However, there are no effective, long-lasting treatments for anaplastic thyroid cancer (ATC), which has a median survival of five to six months. While the receptor tyrosine kinase inhibitor sorafenib can extend ATC patient survival to eleven months, tumor reoccurrence and drug resistance often develop. Therefore, there is a need for more effective targeted therapies for ATC. While the cell signaling landscape is well described in ATC, little is known about tumorigenic adaptations in ATC metabolism. Tumors exhibit an increased consumption of glucose compared to normal tissues to fuel tumor progression. Some cancers meet this high glucose requirement by storing and breaking down glycogen. While glycogen has been detected in bovine and canine thyroids, no report thus far has investigated glycogen in normal human thyroids or thyroid cancer. Therefore, our objective was to determine if normal thyroid and TC cells metabolize glycogen and to evaluate pharmacological inhibition of glycogen metabolism in ATC cells. We show for the first time that normal thyroid, PTC, FTC, and ATC cells express glycogen synthase and glycogen phosphorylase brain and liver (PYGB, PYGL) isoforms. We confirmed these observations in patient samples of normal thyroid and TC tissues via immunofluorescence. We revealed that the TC samples expressed high levels of PYGB compared to normal thyroid tissue. Electron microscopy revealed that normal thyroid cells organized glycogen in discrete glycosomes, while ATC cells exhibited smaller, dispersed glycogen packets. Importantly, we demonstrated that the glycogen synthase inhibitor guaiacol depleted glycogen content and reduced ATC cell viability. Conversely, the glycogen phosphorylase inhibitor CP-91,149 (CP) increased glycogen levels and induced apoptosis. Importantly, CP also reduced the number of stem cells in the ATC cell population. We further showed that CP synergized with sorafenib to more effectively inhibit ATC proliferation. CP enhanced glycolysis but inhibited oxidative phosphorylation as revealed using Seahorse. We confirmed an increase in glucose transporter expression using RT-qPCR and glucose import following CP treatment. This possibly represents a futile response to PYGB inhibition. We reasoned that glycogen was preferentially metabolized in ATC to fuel the pentose phosphate pathway to protect against reactive oxygen species (ROS). Indeed, we detected significantly higher levels of ROS in ATC cells treated with CP. We demonstrated that thyroid cells are able to metabolize glycogen and identified a potential biomarker for thyroid cancer (PYGB), which was targeted with CP-91,149. Our work establishes glycogen metabolism as a novel metabolic process in thyroid cells that is associated with TC dedifferentiation and provides insight to the effectiveness of inhibiting glycogen metabolism as a novel therapeutic strategy in ATC. Citation Format: Cole Davidson, Jennifer Tomczak, Eyal Amiel, Frances Carr. Glycogen phosphorylase and synthase inhibitors: Novel therapeutic approaches in anaplastic thyroid cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P148.

Disruption of Hydrogen Gas Synthesis Enhances the Cellular Levels of NAD(P)H, Glycogen, Poly(3-hydroxybutyrate) and Photosynthetic Pigments Under Specific Nutrient Condition(s) in Cyanobacterium Synechocystis sp. PCC 6803

In photoautotrophic Synechocystis sp. PCC 6803, NADPH is generated from photosynthesis and utilized in various metabolism, including the biosynthesis of glyceraldehyde 3-phosphate (the upstream substrate for carbon metabolism), poly(3-hydroxybutyrate) (PHB), photosynthetic pigments, and hydrogen gas (H2). Redirecting NADPH flow from one biosynthesis pathway to another has yet to be studied. Synechocystis's H2 synthesis, one of the pathways consuming NAD(P)H, was disrupted by the inactivation of hoxY and hoxH genes encoding the two catalytic subunits of hydrogenase. Such inactivation with a complete disruption of H2 synthesis led to 1.4-, 1.9-, and 2.1-fold increased cellular NAD(P)H levels when cells were cultured in normal medium (BG11), the medium without nitrate (-N), and the medium without phosphate (-P), respectively. After 49-52 d of cultivation in BG11 (when the nitrogen source in the media was depleted), the cells with disrupted H2 synthesis had 1.3-fold increased glycogen level compared to wild type of 83-85% (w/w dry weight), the highest level reported for cyanobacterial glycogen. The increased glycogen content observed by transmission electron microscopy was correlated with the increased levels of glucose 6-phosphate and glucose 1-phosphate, the two substrates in glycogen synthesis. Disrupted H2 synthesis also enhanced PHB accumulation up to 1.4-fold under -P and 1.6-fold under -N and increased levels of photosynthetic pigments (chlorophyll a, phycocyanin, and allophycocyanin) by 1.3- to 1.5-fold under BG11. Thus, disrupted H2 synthesis increased levels of NAD(P)H, which may be utilized for the biosynthesis of glycogen, PHB, and pigments. This strategy might be applicable for enhancing other biosynthetic pathways that utilize NAD(P)H.

Early diagnostic and prognostic criteria for health disorders in chemical workers.

The production of synthetic materials - fiberglass and rubber-technical products, as well as products derived from oil refining wastes continues to grow. A characteristic feature of the working conditions of these enterprises is the content of chemicals of hazard class 1-4, which may be potentially hazardous to workers. It imperative to justify prenosological laboratory criteria for health problems of manufacturing workers. The results of the hematological, biochemical, immunological and cytochemical parameters among manufacturing workers are presented. Significant changes in the processes of oxidative metabolism, lipid metabolism, impaired immune status, and intracellular enzyme activity were found in a significant proportion of the workers. Changes were detected in workers even with a short work experience (5 years) and of young age (20-30 years). With an increase in the occupational length of service, the frequency of these disorders increased. Based on the results obtained, early diagnostic and prognostic criteria for health disorders in workers of diverse chemical industries are substantiated. Based on the results obtained, early diagnostic and prognostic criteria for health disorders in workers of diverse chemical industries are substantiated. For rubber manufacturing workers: increased malonic dialdehyde, reduced catalase activity, the activity of catalase is lowering; increased enzymes activity (AST, ALT, GGT), protein abnormalities, erythropenia, decreased hemoglobin levels, increased reticulocyte. For fiber glass manufacturing workers: indicators of the oxidative antioxidant system, hemograms - increased lymphocytes, erythrocytosis, leukocytosis, increased CD3 +, increased CD4 +, CD 16+, CD 20 +, FAL, IgG, increased total protein, hyperfermentemia (GGT, ALT), changes in the intracellular enzymes activity - acid phosphatase of neutrophils and lymphocytes, decreased myeloperoxidase, increased glycogen levels. For olefin oxides manufacturing workers - this is hyperfermentemia (ALT, alkaline phosphatase), protein metabolism changes, increased red blood cells, reticulocytes, neutrophils, lymphocytes, eosinophils, platelets, leucopenia, decreased FAL, increased IgM, decreased IgA, IgG, changes in the intracellular enzymes activity - decrease myeloperoxidase, increase acid phosphatase of neutrophils and lymphocytes.

Supplementation with embryo chicken egg extract improves exercise performance and exerts anti-fatigue effects via AMPK/mTOR signalling pathway in mice.

Embryo chicken egg is a nutritional supplement that has been used to enhance physical fitness and promote wound healing according to traditional Chinese medicine for many years. In this study, we evaluated the effects of embryo chicken egg extract (ECE) on the exercise performance and fatigue in mice and the underlying mechanisms. The results indicated that ECE can prolong the exhaustive swimming time, decrease lactic acid, blood urea nitrogen, creatine kinase, and malondialdehyde levels, and increase superoxide dismutase, glutathione peroxidase, and glycogen levels. Additionally, ECE can also regulate the balance of oxidative stress via the adenosine monophosphate activated protein kinase/mammalian target of rapamycin signalling pathway. Taken together, these results showed that ECE can improve exercise performance and reduce physical fatigue in mice, which indicates that ECE can be used as a potential supplement to reduce physical fatigue. © 2020 Society of Chemical Industry.

Floral Resources for Trissolcus japonicus, a Parasitoid of Halyomorpha halys.

The egg parasitoid Trissolcus japonicus is the main candidate for classical biocontrol of the invasive agricultural pest Halyomorpha halys. The efficacy of classical biocontrol depends on the parasitoid’s survival and conservation in the agroecosystem. Most parasitoid species rely on floral nectar as a food source, thus identifying nectar sources for T. japonicus is critical. We evaluated the impact of eight flowering plant species on T. japonicus survival in the lab by exposing unfed wasps to flowers inside vials. We also measured the wasps’ nutrient levels to confirm feeding and energy storage using anthrone and vanillin assays adapted for T. japonicus. Buckwheat, cilantro, and dill provided the best nectar sources for T. japonicus by improving median survival by 15, 3.5, and 17.5 days compared to water. These three nectar sources increased wasps’ sugar levels, and cilantro and dill also increased glycogen levels. Sweet alyssum, marigold, crimson clover, yellow mustard, and phacelia did not improve wasp survival or nutrient reserves. Further research is needed to determine if these flowers maintain their benefits in the field and whether they will increase the parasitism rate of H. halys.

Metabolic responses to intermittent hypoxia are regulated by sex and gonadal hormones in mice.

Sleep apnea is a respiratory disease characterized by intermittent hypoxia (IH) due to repeated obstructions of the airways during sleep. Men and women after menopause are more likely to develop sleep apnea than women before menopause. In addition to disrupting sleep quality, sleep apnea is strongly associated with metabolic syndrome and type 2 diabetes, and the metabolic consequences of sleep apnea may vary according to sex or the hormonal status. We therefore used intact males, intact females, and ovariectomized (OVX) female mice to ask if IH induces sex‐specific metabolic responses and if endogenous female hormones prevent these effects. Within each group, mice were exposed to room air (RA) or IH (nadir 6% O2, 10 cycles/hour, 12 hours/day) during 2 weeks. Body weights were measured before and after the exposures to IH. At the end of the IH exposures, mice were fasted for 6 hours, a blood sample was drawn from the saphenous vein to measure fasting plasma glucose and insulin levels. We then performed intraperitoneal insulin or glucose tolerance tests to further assess glucose homeostasis. In distinct groups, we assessed liver levels of glycogen, triglycerides (TG), and expression levels of selected genes involved in glucose metabolism. In intact males, IH reduced weight gain, lowered the fasting levels of glucose and insulin in plasma, and slightly increased glucose tolerance. In intact females, the only effect of IH was a modest decrease of glucose tolerance. In OVX females, IH exposures reduced fasting glucose and insulin levels, induced insulin resistance, and led to a major glucose intolerance. In the liver, IH exposures slightly increased glycogen levels in males and OVX females and had a profound effect to decrease TG levels only in males. The expression levels of key liver glycolytic (LDH) and mitochondrial (Citrate synthase, PDH, PDK) genes were reduced by IH in males or in OVX females. We conclude that the metabolic consequences of IH exposures are sex specific. In females, endogenous ovarian hormones appear to prevent the development of a major glucose intolerance during IH exposure and help maintaining a normal expression pattern of hepatic genes involved in glucose metabolism. Surprisingly, the effects of IH are different in males and OVX females, suggesting that endogenous testosterone might also have a role in males.Support or Funding InformationSupported by CIHR.

Antidiabetic efficacies of methanolic and ethyl acetate extracts of Aristolochia ringens (Vahl) roots: in vivo comparative studies

Antidiabetic effects of methanol and ethyl acetate extracts of roots of Aristolochia ringens (Vahl) were comparatively assessed in streptozotocin (STZ)-induced rats. Pulverized root of A. ringens was soaked with methanol, filtered, and concentrated to dryness. The resulting residue was subsequently dissolved in ethyl acetate, filtered, and concentrated to dryness to obtain ethyl acetate extract. Methanol and ethyl acetate extracts of A. ringens root yielded 20.50 g (10.25%) and 16.4 g (8.2%) respectively. Both extracts (150 mg/kg bw) and metformin (14.2 mg/kg bw) used as reference were administered orally to STZ-induced diabetic rats for 7 days. Fasting blood glucose (FBG) level was monitored and percentage reduction in glycemia computed. Hepatic concentrations of glucose and glycogen as well as alpha amylase and glucose-6-phosphate dehydrogenase activities were also evaluated. FBG level persisted in animals that were diabetic but not treated (323.20 ± 1.01 mg/dL), whereas FBG levels in treated rats following administration of metformin, ethyl acetate, and methanol extracts for 7 days were 148.55 ± 1.62, 129.08 ± 2.52, and 181.21 ± 0.44 mg/dL, resulting in percentage reduction of 80.93%, 85.44%, and 69.10% in glycemia respectively. Ethyl acetate extracts from A. ringens root caused higher reduction in hepatic glucose concentration with concomitant increase in glycogen level when compared to the methanol extract. The root extracts also stimulated the activity of glucose-6-phosphate dehydrogenase while inhibiting the activity of α-amylase in the liver of the treated groups compared to the untreated groups. Findings from this study revealed that ethyl acetate extract of Aristolochia ringens displayed strong antidiabetic potential than the methanol extract of the same plant.

The bioaccumulation of waterborne zinc in tissues of silver catfish (Rhamdia quelen) and its effect on biochemical parameters.

Silver catfish (Rhamdia quelen) is a fish species with neotropical distribution, and is a potential model organism to study polluted environment. The aim of this study is to analyze the response of silver catfish to environmental concentrations of waterborne zinc (Zn) over 96h. Significant metal accumulation was seen in gill, intestine and liver tissues. No significant accumulation was seen in muscle tissue. Lipid peroxidation increased in the brain, and decreased in the muscle and liver at all levels of exposure. Zinc exposure led to decreased protein carbonyl levels in the brain and increased levels in the liver. The activity of catalase in the liver was reduced for all exposed groups. Glutathione S-transferase activity decreased in the brain at the highest level of exposure and in the liver at all Zn concentrations tested. Non-protein thiols increased in the muscle and in the gills after exposure. Ascorbic acid levels increased in the brain and in the gills. Exposure to Zn also altered the metabolic parameters, causing decreased lactate and ammonia levels in the muscle, and decreased glycogen in the liver. Zinc exposure increased ammonia and amino acid levels in the liver, and increase glycogen and amino acid levels in muscle tissue. Our results demonstrate that exposure to environmentally relevant concentrations of Zn led to accumulation of metals in the tissues of silver catfish, with significant changes in biochemical parameters.

The effect of Psidium guajava aqueous leaf extract on liver glycogen enzymes, hormone sensitive lipase and serum lipid profile in diabetic rats

Diabetes mellitus is characterized by hyperglycaemia that results from defects in insulin secretion or insulin action and is accompanied by general disturbances metabolism. Psidium guajava (PG) leaf is known to have antidiabetic effects that include lowering of blood glucose. The aim of the study was to investigate the effect of PG leaf extract on tissue activity of glycogen synthase (GS) and glycogen phosphorylase (GP); tissue activity of hormone sensitive lipase (HSL); serum lipid profile; and serum enzyme biomarkers of tissue damage. Diabetes was induced in male Sprague-Dawley rats with a single dose of 40 mg/kg body weight streptozotocin. The aqueous extract of PG leaves was used to treat both normal and diabetic animals (400 mg/kg body weight) for 2 weeks while control animals were treated with the vehicle. At the end of the treatment period, blood, liver and adipose tissue samples were collected from the euthanized animals. The results show that PG extract significantly decreased (P < 0.05) HSL activity in adipose tissue and liver of diabetic animals which was accompanied by increased glycogen levels, reduced serum triglycerides, total cholesterol, LDL-cholesterol and increased HDL-cholesterol. This study demonstrates that P. guajava has significant anti-diabetic effects that include increased glycogen storage and reduced HSL activity in the liver and adipose tissue with an improved serum lipid profile.

Insulin-Like Peptides Regulate Feeding Preference and Metabolism in Drosophila.

Fruit flies have eight identified Drosophila insulin-like peptides (DILPs) that are involved in the regulation of carbohydrate concentrations in hemolymph as well as in accumulation of storage metabolites. In the present study, we investigated diet-dependent roles of DILPs encoded by the genes dilp1–5, and dilp7 in the regulation of insect appetite, food choice, accumulation of triglycerides, glycogen, glucose, and trehalose in fruit fly bodies and carbohydrates in hemolymph. We have found that the wild type and the mutant lines demonstrate compensatory feeding for carbohydrates. However, mutants on dilp2,3, dilp3, dilp5, and dilp7 showed higher consumption of proteins on high yeast diets. To evaluate metabolic differences between studied lines on different diets we applied response surface methodology. High nutrient diets led to a moderate increase in concentration of glucose in hemolymph of the wild type flies. Mutations on dilp genes changed this pattern. We have revealed that the dilp2 mutation led to a drop in glycogen levels independently on diet, lack of dilp3 led to dramatic increase in circulating trehalose and glycogen levels, especially at low protein consumption. Lack of dilp5 led to decreased levels of glycogen and triglycerides on all diets, whereas knockout on dilp7 caused increase in glycogen levels and simultaneous decrease in triglyceride levels at low protein consumption. Fruit fly appetite was influenced by dilp3 and dilp7 genes. Our data contribute to the understanding of Drosophila as a model for further studies of metabolic diseases and may serve as a guide for uncovering the evolution of metabolic regulatory pathways.

Assay for hypoglycemic functional food of cocoyam (Xanthosoma sagittifolium (L.) Schott.) tuber

Diabetes Mellitus (DM) type II is a degenerative disease that is a major killer in many countries. It is characterized by an increase of the blood glucose level above normal. It is important to choose an appropriate food sources using glycemic index (GI) concept in order to prevent blood glucose increase. One of Indonesian traditional carbohydrate source is cocoyam (Xanthosoma sagittifolium (L.) Schott.) tuber. The tuber is assumed having a higher carbohydrate content with lower GI. The research aims to measure GI of cocoyam tuber (CT) and determine glucose and glycogen level in animal model after CT fed. Experimental research was carried out by using completely randomized design. We used twenty four male rats as animal models. They were grouped in to 4 different treatments. Group I was treated with standard feed, group II was treated with standard feed and glucose, group III was treated with steamed CT, and group IV was treated hypoglicemic agent standard, glibencamide. The research results that GI of steamed CT was low. It was 54. Blood glucose of diabetic rats after fed by CT decreased significantly (p<0.05), similar to diabetic rats after treated by glibencamide. Whereas glycogen level in diabetic rats after fed by CT was higher than in diabetic rats after fed by standard feed. Cocoyam tuber increased glycogen level in diabetic rats significantly (p<0,05). Glycogen level in diabetic rats fed by CT was as high as in healthy rats. Therefore CT is potential consumed for DM type II patients.