scholarly journals Role for leptin in promoting glucose mobilization during acute hyperosmotic stress in teleost fishes

2013 ◽  
Vol 220 (1) ◽  
pp. 61-72 ◽  
Author(s):  
David A Baltzegar ◽  
Benjamin J Reading ◽  
Jonathon D Douros ◽  
Russell J Borski
Keyword(s):  
Amino Acid ◽  
Plasma Glucose ◽  
Metabolic Regulation ◽  
Leptin Receptor ◽  
Control Fish ◽  
Plasma Metabolites ◽  
Endocrine Regulation ◽  
Glucose Levels ◽  
Lactate Levels

Osmoregulation is critical for survival in all vertebrates, yet the endocrine regulation of this metabolically expensive process is not fully understood. Specifically, the function of leptin in the regulation of energy expenditure in fishes, and among ectotherms, in general, remains unresolved. In this study, we examined the effects of acute salinity transfer (72 h) and the effects of leptin and cortisol on plasma metabolites and hepatic energy reserves in the euryhaline fish, the tilapia (Oreochromis mossambicus). Transfer to 2/3 seawater (23 ppt) significantly increased plasma glucose, amino acid, and lactate levels relative to those in the control fish. Plasma glucose levels were positively correlated with amino acid levels (R2=0.614), but not with lactate levels. The mRNA expression of liver leptin A (lepa), leptin receptor (lepr), and hormone-sensitive and lipoprotein lipases (hslandlpl) as well as triglyceride content increased during salinity transfer, but plasma free fatty acid and triglyceride levels remained unchanged. Both leptin and cortisol significantly increased plasma glucose levelsin vivo, but only leptin decreased liver glycogen levels. Leptin decreased the expression of liverhslandlplmRNAs, whereas cortisol significantly increased the expression of these lipases. These findings suggest that hepatic glucose mobilization into the blood following an acute salinity challenge involves both glycogenolysis, induced by leptin, and subsequent gluconeogenesis of free amino acids. This is the first study to report that teleost leptin A has actions that are functionally distinct from those described in mammals acting as a potent hyperglycemic factor during osmotic stress, possibly in synergism with cortisol. These results suggest that the function of leptin may have diverged during the evolution of vertebrates, possibly reflecting differences in metabolic regulation between poikilotherms and homeotherms.

Rapid translocation of hepatic glucokinase in response to intraduodenal glucose infusion and changes in plasma glucose and insulin in conscious rats

2004 ◽  
Vol 286 (4) ◽  
pp. G627-G634 ◽  
Author(s):  
Chang An Chu ◽  
Yuka Fujimoto ◽  
Kayano Igawa ◽  
Joseph Grimsby ◽  
Joseph F. Grippo ◽  
...  
Keyword(s):  
Portal Vein ◽  
Plasma Glucose ◽  
Regulatory Protein ◽  
Glucose Infusion ◽  
Insulin Levels ◽  
Conscious Rats ◽  
Glucose Levels ◽  
Glucose Ingestion ◽  
Plasma Insulin Levels

The rate of liver glucokinase (GK) translocation from the nucleus to the cytoplasm in response to intraduodenal glucose infusion and the effect of physiological rises of plasma glucose and/or insulin on GK translocation were examined in 6-h-fasted conscious rats. Intraduodenal glucose infusion (28 mg·kg-1·min-1 after a priming dose at 500 mg/kg) elevated blood glucose levels (mg/dl) in the artery and portal vein from 90 ± 3 and 87 ± 3 to 154 ± 4 and 185 ± 4, respectively, at 10 min. At 120 min, the levels had decreased to 133 ± 6 and 156 ± 5, respectively. Plasma insulin levels (ng/ml) in the artery and the portal vein rose from 0.7 ± 0.1 and 1.8 ± 0.3 to 11.8 ± 1.5 and 20.2 ± 2.0 at 10 min, respectively, and 12.4 ± 3.1 and 18.0 ± 4.8 at 30 min, respectively. GK was rapidly exported from the nucleus as determined by measuring the ratio of the nuclear to the cytoplasmic immunofluorescence (N/C) of GK (2.9 ± 0.3 at 0 min to 1.7 ± 0.2 at 10 min, 1.5 ± 0.1 at 20 min, 1.3 ± 0.1 at 30 min, and 1.3 ± 0.1 at 120 min). When plasma glucose (arterial; mg/dl) and insulin (arterial; ng/ml) levels were clamped for 30 min at 93 ± 7 and 0.7 ± 0.1, 81 ± 5 and 8.9 ± 1.3, 175 ± 5 and 0.7 ± 0.1, or 162 ± 5 and 9.2 ± 1.5, the N/C of GK was 3.0 ± 0.5, 1.8 ± 0.1, 1.5 ± 0.1, and 1.2 ± 0.1, respectively. The N/C of GK regulatory protein (GKRP) did not change in response to the intraduodenal glucose infusion or the rise in plasma glucose and/or insulin levels. The results suggest that GK but not GKRP translocates rapidly in a manner that corresponds with changes in the hepatic glucose balance in response to glucose ingestion in vivo. Additionally, the translocation of GK is induced by the postprandial rise in plasma glucose and insulin.

Response to intravenous injections of amylin and glucagon in fasted, fed, and hypoglycemic rats

1993 ◽  
Vol 264 (6) ◽  
pp. E943-E950 ◽  
Author(s):  
A. A. Young ◽  
G. J. Cooper ◽  
P. Carlo ◽  
T. J. Rink ◽  
M. W. Wang
Keyword(s):  
Plasma Glucose ◽  
Insulin Infusion ◽  
Sodium Lactate ◽  
Plasma Lactate ◽  
Glucose Response ◽  
Intravenous Injections ◽  
Glucose Levels ◽  
Fasted State ◽  
Islet Hormone ◽  
Lactate Levels

The actions of intravenous glucagon and amylin, a newly discovered hyperglycemic pancreatic islet hormone, have been compared in 20-h fasted and fed, lightly anesthetized rats, and in rats made hypoglycemic with an insulin infusion. In fasted animals, amylin (75 nmol/kg) was more effective than glucagon (90 nmol/kg) in increasing plasma glucose (glucose increment 4.55 vs. 1.71 mM, P < 0.001). Amylin elicited a marked increase in plasma lactate, as previously reported, whereas glucagon did not alter plasma lactate. In fed animals, glucagon elicited twice as much increase in plasma glucose as did amylin; amylin again elicited a marked lactate increase that was greater (increment 1.45 vs. 0.97 mM, P < 0.05) and more prolonged than in the fasted state, whereas glucagon was without effect on lactate levels. These findings are consistent with glucagon's known action to promote hyperglycemia from hepatic glycogenolysis and amylin's demonstrated action to promote muscle glycogenolysis and increase lactate supply to the liver. Infusions of sodium lactate that produced plasma lactate increments similar to those evoked by 75 nmol/kg amylin evoked patterns of glucose response in fasted and fed rats similar to those evoked by amylin. Thus increased lactate supply to the liver may account for amylin's hyperglycemic effects. Amylin and glucagon could each restore plasma glucose to control levels in fasted animals made hypoglycemic by insulin infusion (plasma glucose reduced to 3.3 mM). A bolus of 75 nmol/kg amylin was more effective than 180 nmol/kg glucagon, restoring basal glucose levels for > 3 h, whereas glucagon restored it for < 1 h.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals A Pilot Study on Antimalarial Effects of Moringa oleifera Leaf Extract in Plasmodium berghei Infection in Mice

2017 ◽  
Vol 15 (2) ◽  
pp. 151-156
Author(s):  
Somrudee NAKINCHAT ◽  
Voravuth SOMSAK
Keyword(s):  
Plasma Glucose ◽  
Crude Extract ◽  
Plasmodium Berghei ◽  
Leaf Extract ◽  
Moringa Oleifera ◽  
Dependent Manner ◽  
Glucose Levels ◽  
New Compounds ◽  
Dose Dependent

The emergence and spread of antimalarial drug resistance of Plasmodium parasites, as well as hypoglycemia, during malaria infection, and subsequent death, are critical problems in malaria-endemic areas. Hence, finding new compounds, especially plant extracts having antimalarial and anti-hypoglycemic activities, are urgently needed. The present study aimed to investigate the antimalarial and anti-hypoglycemic effects of Moringa oleifera leaf extract in Plasmodium berghei infection in mice. Aqueous crude extract of M. oleifera leaves was freshly prepared and used for an efficacy test in vivo. Groups of ICR mice (5 mice in each) were infected with 1´107 infected red blood cells of P. berghei ANKA by intraperitoneal injection and given the extract orally with doses of 100, 500, and 1000 mg/kg for 4 consecutive days. Parasitemia and plasma glucose levels were subsequently measured. The results showed that M. oleifera leaf extract presented significant (p < 0.001) inhibition of parasitemia in a dose-dependent manner. Moreover, this extract exerted anti-hypoglycemia effects in infected mice in a dose-dependent manner. The highest degrees of activity were found at a dose of 1000 mg/kg of the extract. Additionally, no effect on plasma glucose was found in normal mice treated with this extract. It can be concluded that aqueous crude extract of M. oleifera leaves exerted antimalarial and anti-hypoglycemic effects in P. berghei infection in mice.

Regulation of hepatic gluconeogenesis and glycogenolysis by catecholamines in rainbow trout during environmental hypoxia

1989 ◽  
Vol 147 (1) ◽  
pp. 169-188 ◽  
Author(s):  
P. A. Wright ◽  
S. F. Perry ◽  
T. W. Moon
Keyword(s):  
Rainbow Trout ◽  
Plasma Glucose ◽  
Glycogen Phosphorylase ◽  
Active Form ◽  
Glucose Levels ◽  
Mediated Effects ◽  
Inhibition Of Glycolysis ◽  
Pre Treatment ◽  
Lactate Levels ◽  
Liver Glycogenolysis

This study tests the hypothesis that catecholamines regulate glucose availability during hypoxia in the rainbow trout by activating glycogen phosphorylase (GPase) while inhibiting pyruvate kinase (PK) in the liver. The net result would be an increase in liver glycogenolysis and a reduction of glycolysis and/or enhancement of gluconeogenesis. We used the criteria of Stalmans & Hers (1975) and report much lower resting percent GPase a (active) values (20–30%) than those previously published. Dorsal aortic injections of epinephrine or norepinephrine increased plasma glucose (16–46%), had no effect on liver or muscle glycogen levels, decreased the activity of PK, and increased total and percent GPase a activities. Pre-treatment with the beta-adrenoreceptor antagonist propranolol eliminated these effects. During moderate hypoxia, plasma glucose remained unchanged, while lactate levels increased fourfold. When fish were pre-treated with propranolol, hypoxia depressed plasma glucose levels (−26%), total and percent GPase a, and increased PK activity, suggesting that hypoxia mediated the dephosphorylation of these enzymes. We conclude that catecholamines stimulate hepatic beta-adrenoreceptors during hypoxia and sustain plasma glucose levels by nullifying the deleterious effects of hypoxia on metabolic function. The specific metabolic consequences of these catecholamine-mediated effects are an increase in the activity of the active form of GPase and a reduction in PK activity, which suggests an activation of glycogenolysis and an inhibition of glycolysis and/or activation of gluconeogenesis, respectively.

Plasma glucose and insulin responses in growing rats fed a total parenteral nutrition diet either intravenously or intragastrically

1984 ◽  
Vol 62 (7) ◽  
pp. 775-780 ◽  
Author(s):  
Norman S. Track ◽  
Ernest Cutz ◽  
Barbara H. Witt
Keyword(s):  
Amino Acid ◽  
Parenteral Nutrition ◽  
Total Parenteral Nutrition ◽  
Plasma Glucose ◽  
Plasma Insulin ◽  
Glucose Levels ◽  
Group I ◽  
Plasma Insulin Levels ◽  
Group Ii ◽  
Insulin Responses

The effect of administering either intravenously (group I) or intragastrically (group II) a glucose – amino acid total parenteral nutrition diet over a 12-day period upon plasma glucose and insulin responses was examined in adolescent rats. Infusion of the 25% glucose – 12.2% amino acid diet at a rate of 300 kCal∙kg body weight−1∙24 h−1 supported normal weight gain over the 12-day study period in both intravenously (group I) and intragastrically (group II) alimented rats. Mean plasma glucose levels rose dramatically in both groups by the end of day 1; group I had significantly higher mean plasma insulin levels. By day 3, the group I mean plasma glucose value decreased significantly while the group II mean glucose value remained virtually unchanged. Mean plasma insulin values more than doubled in both groups with the group I level still remaining significantly above the group II level. At days 6 and 12, group I mean plasma glucose levels were significantly below group II while both groups had similar plasma insulin levels. Data from this 12-day intravenous–intragastric alimentation study reveals quite different metabolic responses compared with acute (120–180 min) studies of the enteroinsular axis.

Effects of Acute Exposure to Bleached Kraft Pulpmill Effluent on Carbohydrate Metabolism of Juvenile Coho Salmon (Oncorhynchus kisutch) During Rest and Exercise

1975 ◽  
Vol 32 (6) ◽  
pp. 753-760 ◽  
Author(s):  
D. J. McLeay ◽  
D. A. Brown
Keyword(s):  
Plasma Glucose ◽  
Muscle Glycogen ◽  
Coho Salmon ◽  
Liver Glycogen ◽  
Plasma Lactate ◽  
Mean Values ◽  
Glucose Levels ◽  
Lactate Levels ◽  
Sugar Levels ◽  
Glycogen Stores

In the static study (no exercise), liver glycogen stores were unchanged during 12-h exposure to 0.8 of the 96-h LC50; longer exposures caused a progressive decrease to levels one fifth those of controls at 72 h. Plasma glucose levels in fish held in 0.8 LC50 effluent for 3–96 h were elevated; at 96 h, glucose had increased threefold. Mean values for plasma lactate were elevated significantly at 3, 6, 24, 72, and 96 h.In the exercise (swimming one body length per second)–rest study, muscle glycogen levels decreased 53–78% during exercise in water or effluent (0.7 LC50) for 4–12 h, and did not recover during 12-h rest in water. Muscle glycogen for fish exercised for 12 h in effluent and then rested for 4 or 12 h in effluent was lower compared to values for fish exercised in effluent and then rested in water. There was no difference in liver glycogen levels offish exercised in effluent or water for 4–12 h. Values of liver glycogen for fish exercised in effluent for 12 h and then rested for 4, 8, or 12 h in effluent decreased 60–70% compared to fish exercised in water for 12 h and then rested in water and by 55–65% from fish exercised in effluent for 12 h and rested in water for 4–12 h. Plasma glucose levels were elevated one- to fourfold during exercise in water or effluent. Fish resting in water for 4, 8, or 12 h following exercise in water had relatively stable glucose levels; whereas for fish exercised and then rested in effluent the glucose levels increased twofold during resting. Plasma lactate levels were elevated five- to sixfold during exercise in water or effluent for 4–12 h, declining to values 1–2 times those of stock fish within 4-h rest. Plasma lactate levels for fish exercised in effluent and then rested in effluent or water were continually higher than those for fish exercised and rested in water.It was concluded that measurement of carbohydrate metabolites, particularly blood sugar levels, in unexercised fish could prove useful as a rapid method for measuring toxicity of pulpmill effluents and other pollutants.

In vivo effect of Trigonella foenum graecum on the expression of pyruvate kinase, phosphoenolpyruvate carboxykinase, and distribution of glucose transporter (GLUT4) in alloxan-diabetic rats

2006 ◽  
Vol 84 (6) ◽  
pp. 647-654 ◽  
Author(s):  
Sameer Mohammad ◽  
Asia Taha ◽  
Kamal Akhtar ◽  
R.N.K. Bamezai ◽  
Najma Zaheer Baquer
Keyword(s):  
Skeletal Muscle ◽  
Pyruvate Kinase ◽  
Plasma Glucose ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Glucose Transporter ◽  
Diabetic Rats ◽  
Altered Expression ◽  
Glucose Levels ◽  
Glucose Transporter Glut4

Plasma glucose levels are maintained by a precise balance between glucose production and its use. Liver pyruvate kinase (PK) and phosphoenolpyruvate carboxykinase (PEPCK), 2 key enzymes of glycolysis and gluconeogenesis, respectively, play a crucial role in this glucose homeostasis along with skeletal muscle glucose transporter (GLUT4). In the diabetic state, this balance is disturbed owing to the absence of insulin, the principal factor controlling this regulation. In the present study, alloxan-diabetic animals having high glucose levels of more than 300 mmol/L have been taken and the administration of Trigonella seed powder (TSP) to the diabetic animals was assessed for its effect on the expression of PK and PEPCK in liver and GLUT4 distribution in skeletal muscle of alloxan-diabetic rats. TSP treatment to the diabetic animals resulted in a marked decrease in the plasma glucose levels. Trigonella treatment partially restored the altered expression of PK and PEPCK. TSP treatment also corrected the alterations in the distribution of GLUT4 in the skeletal muscle.

Localization of the GLUT8 glucose transporter in murine kidney and regulation in vivo in nondiabetic and diabetic conditions

2005 ◽  
Vol 289 (1) ◽  
pp. F186-F193 ◽  
Author(s):  
Mario Schiffer ◽  
Katalin Susztak ◽  
Mollie Ranalletta ◽  
Amanda C. Raff ◽  
Erwin P. Böttinger ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Kidney Disease ◽  
Plasma Glucose ◽  
Glucose Transporter ◽  
Apoptotic Cell ◽  
Major Complication ◽  
Distal Portion ◽  
Glucose Levels ◽  
Transporter Family

Kidney disease is a major complication of diabetes, and poor glycemic control is associated with the development of diabetic nephropathy. The precise mechanisms that lead to diabetic kidney disease still remain largely unknown and are under current investigation. Because glucose transporters in the kidney play an important role in the local maintenance of intracellular glucose and plasma glucose homeostasis, the tissue distribution and regulation of glucose transporter GLUT8, a new member of the glucose transporter family with important functions in cellular survival, were examined. To understand the normal regulation of GLUT8 expression in response to metabolic signals, fasting and feeding conditions were studied. Additionally, GLUT8 expression was studied using two different models of insulin resistance, GLUT4−/− and db/db mice. GLUT8 was localized to glomerular podocytes and tubular epithelial cells in the distal portion of the nephron. Expression of GLUT8 in the kidney was influenced by plasma glucose levels in vivo. Podocytes in kidneys of diabetic db/db mice express higher levels of GLUT8 compared with nondiabetic db/m mice. Because podocytes play an important role in glomerulosclerosis development and high levels of glucose have been shown to induce apoptotic cell death in various kidney cells, these data may provide further insight into the pathogenesis of glomerulosclerosis and diabetic nephropathy.

scholarly journals Glycemic Index of Selected Indian Rice Varieties

2020 ◽  
pp. 137-146
Author(s):  
M. Mohibbe Azam ◽  
Afifa Jahan ◽  
K. Uma Maheshwari ◽  
T. Ram ◽  
Amtul Waris
Keyword(s):  
Glycemic Index ◽  
Plasma Glucose ◽  
Human Subjects ◽  
Standard Procedure ◽  
Eating Quality ◽  
Quality Traits ◽  
Rice Varieties ◽  
Glucose Levels ◽  
Cooking And Eating Quality

Aims: For prevention and management of type II diabetes among rice eating population, consumption of rice with lower Glycemic Index (GI) is highly desirable as low GI food decreases plasma glucose levels and plasma insulin demand. As there is paucity of information on the GIs of commonly consumed rice varieties in India, the aim of this study was to determine GI of selected five rice varieties, and to find relationship of GI with their cooking and eating quality traits. Study Design, Place and Duration: In vivo experiment was conducted at PG&RC, PJTS Agricultural University, Hyderabad, India, during March, 2017 to February, 2018. During this period, cooking and eating quality traits of selected rice varieties were determined in ICAR- Indian Institute of Rice Research, Hyderabad, India. Methodology: GIs were determined by feeding10 fasted human subjects a fixed portion of foods and subsequently measuring plasma glucose of their blood samples at specific interval of time and GIs were calculated using standard formula. Cooking and eating quality traits were determined using standard procedure. Results: The estimated GI values were 56.38(SEM 1.57), 59.23(SEM 1.02), 71.73 (SEM 1.75), 87.40 (SEM 1.90), and 94.05 (SEM 1.21), respectively for Sampada, Dhanrasi, DRR Dhan 42, DRR Dhan 43, and Jarava. Alkali spreading value (ASV), Gel consistency (GC), and Water uptake (WU) values of these five varieties ranged from 4 to 6, 22 mm to 54.5 mm, and 80 ml/ 100 g to 255 ml/100 g, respectively. Conclusion: Two varieties were identified with moderate GI values (Sampada, 56.38 ± 1.57; Dhanrasi, 59.23± 1.02). These varieties can prove to be a healthier option to incorporate in nutritional therapeutic diet. It is also concluded that lower ASV, higher GC, and lower WU, are good predictors for lower GIs of rice varieties. These relationships may be used for screening of low GI rice cultivars in breeding programme.

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