Liver Glycogen Levels Research Articles

Antioxidant and antidiabetic activities of the seed and leaf extracts of Chrysophyllum albidum

ObjectiveTo investigate the antioxidant and antidiabetic activities of the seed and leaf extracts of Chrysophyllum albidum (C. albidum). MethodsAfter assessing the in vitro ferric reducing power and hydrogen peroxide scavenging activities as well as the flavonoid and flavanol contents, the seed and leaf extracts were administered to diabetic rats for 7 days. The animals were sacrificed and serum was obtained for the determination of blood glucose level while liver sample was used for the quantification of glycogen level as well as lipidic peroxidation and catalase activity. ResultsSeed and leaf extracts of C. albidum showed ferric reducing activity and very high hydrogen peroxide scavenging potential. After the administration of treatment in diabetic rats, there was a significant decrease (P <0.05) in blood sugar level and a significant increase (P<0.05) in liver glycogen level in Groups 3 and 4 animals administered the leaf and seed extracts respectively compared to Group 1 (the negative control). Also, catalase activity and malondialdehyde levels increased in Groups 3 and 4 administered the extracts compared to Group 1 animals (the negative control). Flavonoids and flavanol were present and significantly higher (P<0.05) in the leaf than seed extract. In all, the leaf extract showed the greatest activities. ConclusionsThese results suggest that the leaf and seed extracts of C. albidum possess both in vitro and in vivo antioxidant activities in scavenging free radicals as well as antidiabetic activity, and as such, a potentially important compound in antidiabetic drug discovery.

Anti-Diabetic Activity Of Aqueous Extract Of Pithecellobium Dulce Benth Fruit Peel On Streptozotocin Induced Diabetic Rats

The decoction of the Pithecellobium dulce fruit peel has been used for the control of diabetes mellitus in the traditional method adopted by the local people of northwest region of Tamil Nadu, India. The present study was carried out to investigate the anti-diabetic potential of aqueous extract of Pithecellobium dulce fruit peel by its oral administration (200 mg/kg) to streptozotocin-induced diabetic rats. The levels of blood glucose, urine sugar, glycosylated hemoglobin, glucose-6-phosphatase, fructose-1,6-bisphosphatase, total cholesterol, triglycerides, aspartate transaminase, alanine transaminase, alkaline phosphatase and reduced glutathione were increased significantly whereas the levels of plasma insulin, hexokinase, protein, liver glycogen, reduced glutathione, superoxide dismutase, catalase and glutathione peroxidase were decreased in streptozotocin-induced diabetic rats and it was normalized after treatment of aqueous extract. Glibenclamide was used as the standard drug. These outcomes suggest that the aqueous extract possesses anti-diabetic activity and supports the traditional use of the Pithecellobium dulce fruit peel decoction as hypoglycemic agent.

Reducing the effect of pre-slaughter fasting on the stress response of rainbow trout (Oncorhynchus mykiss)

AbstractFasting is commonly used in aquaculture to empty the gut before slaughter, but little is known about how feeding frequency before fasting affects the stress response of trout. To find out more, 240 rainbow trout (Oncorhynchus mykiss) were separated into three groups with different feeding schedules during the final month of fattening, from 26 September to 28 October 2013 (daily, every two days or every four days) and two durations of pre-slaughter fasting (two days of fasting; 24.3 degree days, to nine days of fasting; 102 degree days). After slaughter, a number of stress-related parameters were measured, such as liver glycogen, skin/gill colour and haematological parameters (cortisol, glucose, lactate, triglycerides, lactate dehydrogenase and creatine phosphokinase). Trout given food every two days on the farm had lower levels of cortisol and higher levels of triglycerides and liver glycogen than the other treatments after two days of fasting; indicating that habituating trout to feed once every two days in the final month of fattening lowered their stress response to two days of fasting before slaughter.

The metabolic consequences of repeated anoxic stress in the western painted turtle, Chrysemys picta bellii

The painted turtle is known for its extreme tolerance to anoxia, but it is unknown whether previous experience with anoxic stress might alter physiological performance during or following a test bout of anoxia. Repeatedly subjecting 25°C-acclimated painted turtles to 2h of anoxic stress every other day for 19days (10 submergence bouts total) caused resting levels of liver glycogen to decrease by 17% and liver citrate synthase (CS) and cytochrome oxidase (COX) activities to increase by 33% and 112%, respectively. When the repeatedly submerged turtles were studied during a subsequent anoxic stress test, liver COX and CS activities decreased during anoxia to the same levels of naïve turtles, which were unchanged, and remained there throughout metabolic recovery. There were no effects of the repeated anoxia treatment on any of the other measured variables, which included lactate dehydrogenase and phosphofructokinase activities in liver, skeletal muscle, and ventricle, blood acid-base status, hemoglobin, hematocrit and plasma ion (Na, K, Ca, Mg, Cl) and metabolite concentrations (lactate, glucose, free-fatty acids), before, during, or after the anoxic stress test. We conclude that although painted turtles can show a physiological reaction to repeated anoxic stress, the changes appear to have no measurable effect on anaerobic physiological performance or ability to recover from anoxia.

Sesame oil in diets for lambari: Effects on growth parameters, corporal chemical composition and physiological alterations

ABSTRACT: The inclusion of sesame oil associated with soybean, linseed and freshwater fish residue oil in the diets fed to Lambaris Astyanax altiparanaewas evaluated by the growth performance parameters, body composition and possible physiological changes (GARUTTI &amp; BRISTSKI, 2000). The experiment was a completely randomized design in two factorial parameters tested: three oil types (soy oil (SO), linseed oil (LO) and freshwater fish residue oil (FRO)), combined or not with sesame oil (SEO), totalizing six treatments and four replications 24 cages, capacity of 0.70m3 (density of 251 fish m-3). The fish (mean weight 2.35g±0.62g and mean length 5.25cm±0.68cm) were fed with the experimental diets twice a day. After 75 days, the following parameters were determined: body chemical composition and fatty acid profile, glycemia, liver (LG) and muscle glycogen (MG) levels, and lipid peroxidation (TBARS). Fish fed with diets containing SEO had higher desaturation index values of LNA while those fed with SEO combined with LO displayed reduced hepatic lipid oxidation. Inclusion of SEO improved the fatty acid profile and stability, without causing problems related to fish performance and health.

Antidiabetic potential of the leaf extract of Centella asiatica in alloxaninduced diabetic rats

The study was designed to evaluate the glucose and cholesterol lowering effect of the aqueous extract of Centella asiatica leaf using the alloxan-induced diabetic rats and compared the activity with diabetic control and antidiabetic drug (Glibenclamide). Leaf extract (50 mg/kg) of C. asiatica and Glibenclamide were administered to normal and experimental diabetic rats for the duration of 10 days. In the alloxan-induced diabetic rat model, C. asiatica extract (50 mg/kg) significantly (p &lt; 0.05) lowered the fasting blood glucose level as well as the total cholesterol level. Serum insulin levels were not stimulated in the animals treated with the extract. In addition, changes in body weight, serum lipid profiles and liver glycogen levels assessed in the extract treated diabetic rats were compared with diabetic control and normal animals. Significant results (p &lt; 0.05) were observed in the estimated parameters. Surprisingly, body weight was increased significantly (p &lt; 0.05) in the C. asiatica treated diabetic group. Phytochemical screening showed the presence of alkaloids, flavonoids, glycosides, steroids and tannins in significant amountsJahangirnagar University J. Biol. Sci. 4(1): 51-59, 2015 (June)

Preconditioning with ethyl 3,4-dihydroxybenzoate augments aerobic respiration in rat skeletal muscle.

Muscle respiratory capacity decides the amount of exertion one’s skeletal muscle can undergo, and endurance exercise is believed to increase it. There are also certain preconditioning methods by which muscle respiratory and exercise performance can be enhanced. In this study, preconditioning with ethyl 3,4-dihydroxybenzoate (EDHB), a prolyl hydroxylase domain enzyme inhibitor, has been investigated to determine its effect on aerobic metabolism and bioenergetics in skeletal muscle, thus facilitating boost in physical performance in a rat model. We observed that EDHB supplementation increases aerobic metabolism via upregulation of HIF-mediated GLUT1 and GLUT4, thus enhancing glucose uptake in muscles. There was also a twofold rise in the activity of enzymes of tricarboxylic acid (TCA) cycle and glycolysis, ie, hexokinase and phosphofructokinase. There was an increase in citrate synthase and succinate dehydrogenase activity, resulting in the rise in the levels of ATP due to enhanced Krebs cycle activity as substantiated by enhanced acetyl-CoA levels in EDHB-treated rats as compared to control group. Increased lactate dehydrogenase activity, reduced expression of monocarboxylate transporter 1, and increase in monocarboxylate transporter 4 suggest transport of lactate from muscle to blood. There was a concomitant decrease in plasma lactate, which might be due to enhanced transport of lactate from blood to the liver. This was further supported by the rise in liver pyruvate levels and liver glycogen levels in EDHB-supplemented rats as compared to control rats. These results suggest that EDHB supplementation leads to improved physical performance due to the escalation of aerobic respiration quotient, ie, enhanced muscle respiratory capacity.

Comparison of Antifatigue Activity of Five Sea Cucumber Species in a Mouse Model of Intense Exercise

Background: Sea cucumber (class Holothuroidea, phylum Echinodermata) is a marine food rich in valuable nutrients and is confirmed to have antifatigue effects. This study aimed to compare the antifatigue activity of five sea cucumber species from China and Thailand. Materials and Methods: A mouse model of effective intense exercise was used. Blood levels of lactic acid (LA), and creatine kinase (CK), liver and muscle glycogen content, malondialdehyde (MDA) content and blood superoxide dismutase (SOD) activity were investigated. Results: Holothuria scabra (Thailand) supplementation decreased blood LA and CK levels from 9.17 ± 0.59 and 0.52 ± 0.03 to 7.82 ± 0.97 mmol/L and 0.40 ± 0.08 U/ml, respectively and increased liver and muscle glycogen levels after intense exercise from 10.70 ± 0.18 and 0.93 ± 0.02 to 14.57 ± 1.61 and 1.02 ± 0.06 mg/g, respectively. Identical results were also obtained in the popular Chinese species A. japonicas. Furthermore, A. japonicus and Thenenota ananas supplementation decreased MDA content significantly (p<0.01 and p<0.05, respectively). A. japonicus, H. scabra, Acaudina molpadioides and Cucumaria frondosa supplementation significantly increased SOD level. Conclusion: The five sea cucumber species, especially A. japonicus and H. scabra, display good antifatigue activities.

Antidiabetic activity of polyherbomineral formulation: Chandrakala rasa

Objective: Chandrakala rasa (CKR), a herbomineral formulation is used to treat diabetes mellitus in ayurvedic system of health care. The present study aims to evaluate the antihyperglycemic potential of CKR in normoglycemic and streptozotocin (STZ)-nicotinamide (NAD)-induced Type 2 diabetic rats. Materials and Methods: Effects of CKR (100, 200 and 400 mg/kg, p.o.) on hypoglycemia as well as on oral glucose tolerance test (OGTT) were evaluated in normoglycemic rats by measuring the blood glucose concentrations. Similarly, blood glucose level was measured after 7, 14 and 21 days in STZ-NAD-induced diabetic rats treated with CKR. Different biochemical parameters such as total cholesterol, triglyceride, low density lipoprotein-cholesterol, and high density lipoprotein-cholesterol were estimated in a blood sample. In vivo antioxidant potential of CKR was measured in isolated liver sample of rats. Results: CKR (400 mg/kg, p.o.) did not show any hypoglycemic effect in normoglycemic rats. In OGTT, it significantly reduced the hike in blood glucose levels within 30-60 min after glucose administration without causing any hypoglycemic effect. Administration of CKR significantly reduced the fasting blood glucose levels on 7th, 14th and 21st days in STZ-NAD-induced diabetic rats. Treatment of rats with CKR reversed plasma lipid profile as well as increases liver glycogen level significantly in STZ-NAD-induced diabetic rats. Treatment with CKR in diabetic rats significantly restored the levels of lipid per-oxidation, superoxide dismutase and catalase as compared to negative control rats. Conclusion: The present study showed that CKR has antidiabetic activity probably because of antioxidant potential

Effect of Total Flavonoids from Vexibia alopecuroides on the Course of Experimental Diabetes in Rats

Total flavonoids from Vexibia alopecuroides administered for two weeks to rats with alloxan diabetes lowered the blood glucose level and increased the lactic-pyruvic acid redox potential and liver glycogen level. Lipid metabolism, the antioxidant protection system, and peroxidation processes showed a distinct tendency to normalize in vivo through the influence of the total flavonoids. In this respect, total flavonoids from V. alopecuroides were as effective in the conducted experiments as the known anti-diabetes agent diabeton.

Extraction, purification and anti-fatigue activity of γ-aminobutyric acid from mulberry (Morus alba L.) leaves.

Mulberry (Morus alba L.) is a tree species of Moraceae widely distributed in Southern China. In the present study, the white crystal of γ-aminobutyric acid (GABA) was purified from mulberry leaves, and its bioactivity was also investigated. The main results were as follows: first, the crude GABA was extracted from mulberry leaves by using biochemical methods. Then, the crude was purified by chromatography over an S-8 macroporous resin, Sephadex G-10, and 732 cation exchange resin to yield a white crystal. Lavage administration and exposure of GABA to male NIH mice showed no adverse effects on their growth and development. In an endurance capacity test, the average loaded-swimming time of medium dose was 111.60% longer than the control (P < 0.01). Further investigations showed that relative to that of model control, the respective blood lactate (BL) concentrations of low- and medium-dose were 28.52% and 28.81% lower (P < 0.05), whereas the levels of blood urea nitrogen (BUN) were 36.83% and 40.54% lower (P < 0.05), and that of liver glycogen (LG) levels were 12.81% and 17.22% lower (P < 0.05). The results indicated that GABA has an advantage over taurine of anti-fatigue effect. These findings were indicative of the anti-fatigue activity of GABA.

Evaluation of &lt;i&gt;in vivo&lt;/i&gt; Antioxidant Potential of the Aerial Parts of &lt;i&gt;Aerva lanata&lt;/i&gt; Linn Juss in Streptozotocin Induced Oxidative Stress Rats

To evaluate the invivo antioxidant activities of methanol (MEAL) and aqueous extracts (AEAL) of aerial parts of Aerva lanata Linn Juss in streptozotocin induced oxidative stress rats which are used in the folklore system for the treatment of diabetes mellitus in India. Rats were divided into seven groups of six rats (n=6) each. Group 1 served as vehicle control using normal saline (0.9 % w/v NaCl), Group 2 served as diabetic control, Group 3 served as standard treated with 0.5 mg/kg of glibenclamide, Group 4 and 5 was treated with MEAL 200 and 400 mg/ kg, p.o., Group 6 and 7 was treated with AEAL 200 and 400 mg/kg, p.o. Phenolic content, antioxidant enzymes, liver glycogen and lipid peroxidation were evaluated and compared with diabetic control. MEAL (400 mg/kg) showed significant increase in the protein, catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), reduced glutathione (GSH), hexokinase and liver glycogen levels (p<0.01) than AEAL when compared with diabetic control. The MEAL at the dose of 400 mg/kg showed significant decrease in thiobarbituric acid reactive substance (TBARS) levels, Glucose 6-phosphatase (G6-pase), Fructose 1,6 biphosphatase (FD-pase). Thus, these results scientifically that confirm that MEAL at the higher dose may effectively normalize the various disorders caused by free radicals and other chemical substances due to the presence of secondary metabolites that exert antioxidant activity.

Administration of Lactobacillus casei and Bifidobacterium bifidum Ameliorated Hyperglycemia, Dyslipidemia, and Oxidative Stress in Diabetic Rats.

Background:The present work was planned to evaluate the antihyperglycemic, lipid-lowering, and antioxidant effect of Lactobacillus casei and Bifidobacterium bifidum in streptozotocin (STZ)-induced diabetic rats.Methods:Single daily dose of 1 × 107 cfu/ml of L. casei and B. bifidum alone and in combination of both was given to Wistar rats orally by gavaging for 28 days. Glucose tolerance test, fasting blood glucose (FBG), lipid profile, and glycosylated hemoglobin (HbA1c) were measured from blood. Glycogen from thigh muscles and liver and oxidative stress parameters from pancreas were analyzed.Results:Administration of L. casei and B. bifidum alone and in combination of both to diabetic rats decreased serum FBG (60.47%, 55.89%, and 56.49%, respectively), HbA1c (28.11%, 28.61%, and 28.28%), total cholesterol (171.69%, 136.47%, and 173.58%), triglycerides (9.935%, 8.58%, and 7.91%), low-density lipoproteins (53.27%, 53.35%, and 52.91%) and very low-density lipoproteins (10%, 8.58%, and 11.15%, respectively) and increased high-density lipoproteins (13.73%, 15.47%, and 15.47%), and insulin (19.50%, 25.80%, and 29.47%, respectively). The treatment also resulted in increase in muscle (171.69%, 136.47%, and 173.58%) and liver (25.82%, 6.63%, and 4.02%) glycogen level. The antioxidant indexes in pancreas of diabetic rats returned to normal level with reduction in lipid peroxidation (30.89%, 46.46%, and 65.36%) and elevation in reduced glutathione (104.5%, 161.34%, and 179.04%), superoxide dismutase (38.65%, 44.32%, and 53.35%), catalase (13.08%, 27%, and 31.52%), glutathione peroxidase (55.56%, 72.23%, and 97.23%), glutathione reductase (49.27%, 88.40%, and 110.86%), and glutathione-S-transferase (140%, 220%, and 246.6%, respectively) on treatment with L. casei, B. bifidum, and combination treatment.Conclusions:Administration of L. casei and B. bifidum alone and in combination of both ameliorated hyperglycemia, dyslipidemia, and oxidative stress in STZ-induced diabetic Wistar rats.

Renoprotective Effects, Protein Thiols and Liver Glycogen Content of Alloxan-induced Diabetic Rats Treated with Different Fractions of Heartwood of Pterocarpus marsupium

Oxidative stress is believed to be a pathogenic factor in the development of diabetic complications. In the present study, we aimed to evaluate the effects of different fractions of heart wood of Pterocarpus marsupium on antioxidant enzyme like protein thiols and also check the efficacy of the extract for the protection of the renal function in alloxan induced diabetic rats. The present study also investigates the levels of liver glycogen which are considered as the best biomarker for assaying the hypoglycemic activity of any drug. Diabetes was induced by administering alloxan dissolved in saline, while the normal control group was given propylene glycol. Diabetes induced animals were randomly assigned into different groups. Blood samples were collected from all the experimental and control groups. Estimation of urea, uric acid and creatinine along with protein thiols was made on day 30 only. At the end, all the animals were sacrificed to collect liver tissue to analyze glycogen content. The 30 days treatment with various extracts (75 mg/kg body wt) significantly lowered protein thiol levels, which probably represents increased utilization for neutralizing free radicals. There was no significant increase in the levels of renal parameters in the extract treated groups which revealed that the employed dose of the extract is nontoxic to the kidney. There was also a significant decrease in the glycogen content in insulin and alcohol-extract treated groups and should be encouraging for the treatment of diabetes mellitus. The extract showed a promising antioxidant effect, as well as hypoglycemic activity, and should be encouraged for the treatment of diabetes.

Ingestion of glucose or sucrose prevents liver but not muscle glycogen depletion during prolonged endurance-type exercise in trained cyclists.

The purpose of this study was to define the effect of glucose ingestion compared with sucrose ingestion on liver and muscle glycogen depletion during prolonged endurance-type exercise. Fourteen cyclists completed two 3-h bouts of cycling at 50% of peak power output while ingesting either glucose or sucrose at a rate of 1.7 g/min (102 g/h). Four cyclists performed an additional third test for reference in which only water was consumed. We employed (13)C magnetic resonance spectroscopy to determine liver and muscle glycogen concentrations before and after exercise. Expired breath was sampled during exercise to estimate whole body substrate use. After glucose and sucrose ingestion, liver glycogen levels did not show a significant decline after exercise (from 325 ± 168 to 345 ± 205 and 321 ± 177 to 348 ± 170 mmol/l, respectively; P > 0.05), with no differences between treatments. Muscle glycogen concentrations declined (from 101 ± 49 to 60 ± 34 and 114 ± 48 to 67 ± 34 mmol/l, respectively; P < 0.05), with no differences between treatments. Whole body carbohydrate utilization was greater with sucrose (2.03 ± 0.43 g/min) vs. glucose (1.66 ± 0.36 g/min; P < 0.05) ingestion. Both liver (from 454 ± 33 to 283 ± 82 mmol/l; P < 0.05) and muscle (from 111 ± 46 to 67 ± 31 mmol/l; P < 0.01) glycogen concentrations declined during exercise when only water was ingested. Both glucose and sucrose ingestion prevent liver glycogen depletion during prolonged endurance-type exercise. Sucrose ingestion does not preserve liver glycogen concentrations more than glucose ingestion. However, sucrose ingestion does increase whole body carbohydrate utilization compared with glucose ingestion. This trial was registered at https://www.clinicaltrials.gov as NCT02110836.

Pre-slaughter administration of glycerol as carbohydrate precursor and osmotic agent to improve carcass and beef quality

Glycerol is a by-product from biodiesel production. This molecule is a carbohydrate precursor, thus it maintains the pH of beef at below 5.8 after slaughter, contributing to the prevention of Dry Firm Dark (DFD) meat. Furthermore, glycerol osmotic properties could contribute to alleviating the effects of some stress situations. The aim of this study was to evaluate the effect of administering crude glycerol (2gkg−1 body weight; via nasogastric tube or in drinking water) 24h prior to the slaughter of young bulls, on plasma parameters, liver glycogen levels, carcass (body weight, dressing percentage, carcass weight and length), and beef quality (proximal composition, pH, colour, water holding capacity (WHC), drip loss, cooking loss, and sensory attributes). In general, the plasma parameters and liver glycogen were not affected by glycerol administration (P>0.05). Transport had a significant effect on total protein, albumin, glucose, sodium, potassium, chloride, and lactate plasma levels. Carcass parameters, proximal composition, pH, colour and sensory attributes were not affected (P>0.05) by glycerol treatment but WHC was (P<0.05). The glycerol did not affect the stress markers in plasma during the transport, carcass or meat quality negatively, but it seems to improve WHC of beef.

Effects of macamides on endurance capacity and anti-fatigue property in prolonged swimming mice

Context: Lepidium meyenii Walp. (Brassicaceae), most commonly known as “maca”, has been used as a food or folk medicine to improve vitality in Peru. Previous research demonstrated that lipid-soluble extract from maca improved swimming endurance capacity. Macamides are considered the typical lipid-soluble markers for maca and proved to have several pharmacological properties, such as improving sexual performance and neuroprotective activies.Objective: The present study investigates the effects of macamides on endurance capacity and anti-fatigue property in prolonged swimming mice.Materials and methods: The Balb/c mice were divided into seven groups: a control group, low-dose groups of N-benzyllinoleamide, N-benzyloleamide, and N-benzylpalmitamide, high-dose groups of these macamides. The macamides groups received the commercial products (12 and 40 mg/kg, ig), while the control group received vehicle for 21 d. On the 14th day, the mice were given the weight-loaded swimming test. On the 21st day, the mice were sacrificed immediately after 90 min swimming, and some biochemical parameters were measured.Results and discussion: Compared with the control group, exhaustive swimming time was significantly prolonged in high-dose group of N-benzyloleamide (p < 0.05); the levels of lactic acid (LD), blood ammonia (BA), and lactate dehydrogenase (LDH) were significantly decreased (p < 0.05), whereas the levels of liver glycogen (LG) and non-esterified fatty acid (NEFA) were significantly increased (p < 0.05) in high-dose group of N-benzyloleamide. The malondialdehyde (MDA) contents in the brain, muscle, and liver were significantly decreased (p < 0.05), whereas superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activities in the brain, muscle, and liver were significantly increased in high-dose group of N-benzyloleamide (p < 0.05).Conclusion: The results indicate that N-benzyloleamide has pharmaceutical property against exercise-induced fatigue, and this effect can be explained by the modulated energy metabolism and improved antioxidant status.

Impairment of Liver Glycogen Storage in the db/db Animal Model of Type 2 Diabetes: A Potential Target for Future Therapeutics?

After the discovery of the db gene in 1966, it was determined that a blood-borne satiety factor was produced excessively, but was not responded to, in db/db mice. This model for type 2 diabetes is widely used since it phenocopies human disease and its co-morbidities including obesity, progressive deterioration in glucose tolerance, hypertension and hyperlipidaemia. Db/db mice, unlike their non-diabetic controls, have consistently elevated levels of liver glycogen, most likely due to hyperphagia. In transmission electron micrographs, liver glycogen usually shows a composite cauliflower-like morphology of large "α particles" (with a wide range of sizes) made up of smaller "β particles" bound together. New studies have explored the size distribution of liver glycogen molecules and found that α particles in db/db mice are more chemically fragile than those in healthy mice, and can readily break apart to smaller β particles. There is evidence that smaller glycogen particles have a higher association with glycogen phosphorylase, a key enzyme involved in glycogen degradation, as well as being degraded more rapidly in vitro; therefore the inability to form stable large glycogen α particles is predicted to result in a faster, less controlled degradation into glucose. The implications of this for glycaemic control remain to be fully elucidated. However, "rescuing" the more fragile diabetic glycogen to decrease hepatic glucose output in type 2 diabetes, may provide a potential therapeutic target which is the subject of this review.

Toxicity of atrazine, glyphosate, and quinclorac in bullfrog tadpoles exposed to concentrations below legal limits.

This work sought to ascertain survival and possible changes in levels of glycogen, triglycerides, total lipids, cholesterol, protein, and lipid peroxidation in gills, liver, and muscle of bullfrog tadpoles (Lithobates catesbeianus) exposed to low concentrations of atrazine (2.5μgL(-1)), glyphosate (18μgL(-1)), and quinclorac (0.025μgL(-1)) at laboratorial conditions. Tadpoles showed a reduction of glycogen and triglyceride in all organs and an increase in lipid peroxidation (LPO) compared with control animals. Total lipid in gills and muscle increased in exposure to atrazine, and gills alone in exposure to glyphosate, but decreased in gills, liver, and muscle after quinclorac. Cholesterol increased in gills and liver after atrazine, in gills and muscle after glyphosate, and decreased in liver after quinclorac. Total protein in gills decreased after exposure to all herbicides, increased in muscle after atrazine, and in liver and muscle after quinclorac. These findings show that at concentrations of these herbicides tested can lead to an increase in energy expenditure to maintain homeostasis and survival of these animals despite the increase in lipid peroxidation levels in all organs analyzed. Responses observed can be one of the factors responsible for the decline in the number of amphibians around the world.

Ethanol-induced hepatic steatosis is modulated by glycogen level in the liver

Alcoholic liver disease (ALD) is a major health problem worldwide and hepatic steatosis is an early response to alcohol consumption. Fat and glycogen are two major forms of energy storage in the liver; however, whether glycogen metabolism in the liver impacts alcohol-induced steatosis has been elusive. In this study, we used a mouse model with overexpression of PPP1R3G in the liver to dissect the potential role of glycogen on alcohol-induced fatty liver formation. PPP1R3G is a regulatory subunit of protein phosphatase 1 and stimulates glycogenesis in the liver. Chronic and binge ethanol (EtOH) feeding reduced glycogen level in the mouse liver and such inhibitory effect of EtOH was reversed by PPP1R3G overexpression. In addition, PPP1R3G overexpression abrogated EtOH-induced elevation of serum levels of alanine aminotransferase and aspartate aminotransferase, increase in liver triglyceride concentration, and lipid deposition in the liver. EtOH-stimulated sterol regulatory element-binding protein (SREBP)-1c, a master regulator of lipogenesis, was also reduced by PPP1R3G overexpression in vivo. In AML-12 mouse hepatocytes, PPP1R3G overexpression could relieve EtOH-induced lipid accumulation and SREBP-1c stimulation. In conclusion, our data indicate that glycogen metabolism is closely linked to EtOH-induced liver injury and fatty liver formation.