Increased Plasma Glucose Research Articles

Effect of Bergenin on the Kidney of C57BL/6J Mice with High Fat-Diet Induced Oxidative Stress

The present study evaluated the protective effect of bergenin on high fat diet (HFD) induced diabetic mice. C57BL/6J mice were segregated in two groups, one fed standard diet (NC) and the other fed HFD for 16 weeks. Mice were fed continuously with high fat diet for 16 weeks and subjected to intragastric administration of bergenin (10, 20 and 40 mg/kg body weight (BW)), metformin (25 mg/kg BW) 9 to 16 weeks. At the end of the treatment nephritic markers, lipid peroxidation product, antioxidant and histopathological examination were carried out to assess the efficacy of the treatment. HFD fed mice showed increased plasma glucose, insulin, altered nephritic markers, antioxidant and histopathological abnormalities. Oral Treatment with bergenin (40 mg/kg BW) showed near normalized levels of plasma glucose, lipid peroxidation product, antioxidants, improved insulin and reduced kidney damage. The effects of bergenin were comparable with standard drug, metformin. These data suggest that bergenin protect kidney from deleterious effect of glucose.

Abstract 614: TRAIL Deletion in Mice Promotes Vascular Insulin Resistance

TNF-related apoptosis-inducing ligand (TRAIL) is protective in cardiovascular disease and diabetes; whether it regulates insulin resistance and inflammation in the vessel wall is unknown. Wildtype and Trail -/- mice were placed on a high fat diet (HFD) for 12 w. Plasma chemistries were assessed; glucose and insulin tolerance tests performed. Histological GLUT4 expression in skeletal muscle was assessed. Aortic inflammatory marker expression and downstream insulin signaling was also measured; myography was performed. In response to a HFD for 12 w, wildtype mice had increased aortic IL-1beta, MCP-1, IL-6, TNF-alpha and TRAIL mRNA, with reduced circulating TRAIL levels. Compared to 12 w HFD-fed wildtype mice, Trail -/- mice had significantly increased plasma glucose, insulin, and cholesterol levels. Insulin intolerance was worse with TRAIL deletion, with reduced GLUT4 expression and glucose uptake in skeletal muscle. In response to insulin, Trail -/- aortas displayed impaired vasorelaxation and reduced aortic p-Akt expression. Importantly, aortic insulin resistance was associated with > 20-fold increased aortic mRNA expression for IL-1beta, IL-6, and TNF-alpha. We show that TRAIL protects against insulin resistance and type-2 diabetes, in part by regulating downstream insulin signals and inflammation in the vessel wall. These findings suggest that TRAIL may offer a novel therapeutic solution to combat inflammation and insulin resistance in diabetic vascular diseases.

Intake of Protein Plus Carbohydrate during the First Two Hours after Exhaustive Cycling Improves Performance the following Day.

Intake of protein immediately after exercise stimulates protein synthesis but improved recovery of performance is not consistently observed. The primary aim of the present study was to compare performance 18 h after exhaustive cycling in a randomized diet-controlled study (175 kJ·kg-1 during 18 h) when subjects were supplemented with protein plus carbohydrate or carbohydrate only in a 2-h window starting immediately after exhaustive cycling. The second aim was to investigate the effect of no nutrition during the first 2 h and low total energy intake (113 kJ·kg-1 during 18 h) on performance when protein intake was similar. Eight endurance-trained subjects cycled at 237±6 Watt (~72% VO2max) until exhaustion (TTE) on three occasions, and supplemented with 1.2 g carbohydrate·kg-1·h-1 (CHO), 0.8 g carbohydrate + 0.4 g protein·kg-1·h-1 (CHO+PRO) or placebo without energy (PLA). Intake of CHO+PROT increased plasma glucose, insulin, and branch chained amino acids, whereas CHO only increased glucose and insulin. Eighteen hours later, subjects performed another TTE at 237±6 Watt. TTE was increased after intake of CHO+PROT compared to CHO (63.5±4.4 vs 49.8±5.4 min; p<0.05). PLA reduced TTE to 42.8±5.1 min (p<0.05 vs CHO). Nitrogen balance was positive in CHO+PROT, and negative in CHO and PLA. In conclusion, performance was higher 18 h after exhaustive cycling with intake of CHO+PROT compared to an isocaloric amount of carbohydrate during the first 2 h post exercise. Intake of a similar amount of protein but less carbohydrate during the 18 h recovery period reduced performance.

Effect of diphenyl diselenide diet supplementation on oxidative stress biomarkers in two species of freshwater fish exposed to the insecticide fipronil

The ability of diphenyl diselenide [(PhSe)2] to attenuate oxidative damage was evaluated in the liver, gills, brain, and muscle of carp (Cyprinus carpio) and silver catfish (Rhamdia quelen) experimentally exposed to fipronil (FPN). Initially, the fish were fed a diet without (PhSe)2 or a diet containing 3.0mg/kg of (PhSe)2 for 60days. After the 60-day period, the fish were exposed to 0.65µg/L of FPN for 192h. The results showed that carp exposed to FPN and not fed with (PhSe)2 exhibited acetylcholinesterase (AChE) inhibition in brain and muscle, and increased thiobarbituric acid-reactive substance (TBARS) in liver, gills, and brain. Furthermore, FPN decreased nonprotein thiols (NPSH) and δ-aminolevulinate dehydratase (δ-ALA-D) in carp liver and gills, and increased plasma glucose and protein levels. In silver catfish, FPN inhibited AChE and increased TBARS levels in muscle. In addition, glutathione S-transferase (GST) decreased in liver and muscle, and plasma glucose was increased. (PhSe)2 reversed some of these effects. It prevented the increase in TBARS levels in liver, gills, and brain in carp and in silver catfish muscle, and reversed the increase in plasma glucose levels in both species. Additionally, (PhSe)2 increased the NPSH levels in carp and silver catfish that had decreased in response to FPN exposure. However, (PhSe)2 was not effective in reversing the AChE inhibition in brain and muscle or the δ-ALA-D decrease in carp liver. Thus, (PhSe)2 protects tissues of both species of fish, mainly by preventing or counteracting the effects of FPN, on TBARS levels, antioxidants, and present anti-hyperglycemic property.

Bidirectional electromagnetic control of the hypothalamus regulates feeding and metabolism.

Targeted, temporally regulated neural modulation is invaluable in determining the physiological roles of specific neural populations or circuits. Here we describe a system for non-invasive, temporal activation or inhibition of neuronal activity in vivo and its use to study central nervous system control of glucose homeostasis and feeding in mice. We are able to induce neuronal activation remotely using radio waves or magnetic fields via Cre-dependent expression of a GFP-tagged ferritin fusion protein tethered to the cation-conducting transient receptor potential vanilloid 1 (TRPV1) by a camelid anti-GFP antibody (anti-GFP-TRPV1). Neuronal inhibition via the same stimuli is achieved by mutating the TRPV1 pore, rendering the channel chloride-permeable. These constructs were targeted to glucose-sensing neurons in the ventromedial hypothalamus in glucokinase-Cre mice, which express Cre in glucose-sensing neurons. Acute activation of glucose-sensing neurons in this region increases plasma glucose and glucagon, lowers insulin levels and stimulates feeding, while inhibition reduces blood glucose, raises insulin levels and suppresses feeding. These results suggest that pancreatic hormones function as an effector mechanism of central nervous system circuits controlling blood glucose and behaviour. The method we employ obviates the need for permanent implants and could potentially be applied to study other neural processes or used to regulate other, even dispersed, cell types.

Effects of dry period length and dietary energy source on milk yield, energy balance, and metabolic status of dairy cows over 2 consecutive years: Effects in the second year

The objective of the current study was to evaluate the effect of dry period (DP) length on milk yield, energy balance (EB), and metabolic status in cows fed a lipogenic or glucogenic diet in the second year after implementation of DP and dietary treatments. Holstein-Friesian dairy cows (n=167) were assigned randomly to 1 of 3 DP lengths (0, 30, or 60d) and 1 of 2 early lactation diets (glucogenic or lipogenic) for 2 consecutive years. Results of the first year were reported previously. In the second year, 19 cows in the 0-d DP group were attributed to a new group (0→67d DP) because these cows had a milk yield of <4kg/d at least 30d before expected calving date and were dried off. Milk yield was recorded and EB was calculated from wk –8 to 9 relative to calving. Blood samples were taken weekly from wk –3 to 8 relative to calving. Liver samples were taken in wk –2, 2, and 4 relative to calving. At the onset of lactation, cows with a 0-d or 0→67-d DP had greater body condition score (BCS) than cows with a 60-d DP. During the first 9wk, cows with a 0- or 30-d DP produced 5.0 and 4.3kg less milk per day, respectively, but had similar EB compared with cows with a 60-d DP. Cows with a 0- or 30-d DP produced additional milk precalving, which could compensate milk yield losses in the first 9wk postcalving. Cows with a 0-d DP did not have milk yield losses or improve EB in the second year as much as in the first year. Cows with a 0-d DP had greater plasma insulin and insulin-like growth factor-I (IGF-I) and lower liver triacylglycerol concentrations than cows with other DP lengths. Cows with a 0→67-d DP had lower EB, and greater plasma free fatty acids (FFA) and β-hydroxybutyrate (BHB) concentrations than cows with other DP lengths. Feeding a glucogenic diet increased plasma glucose, IGF-I, and insulin concentrations, and decreased plasma FFA, BHB, and urea concentrations compared with a lipogenic diet, independent of DP length. In conclusion, omitting the DP or feeding a glucogenic diet improved metabolic status in early lactation of the second year after implementation of DP length and dietary treatments, although effects of omitting the DP were less pronounced in the second year than in the first year. The less pronounced improvement of EB in the second year was related to the high BCS at the onset of lactation and reduced milk yield losses in cows with a 0-d DP.

Cold temperature blocks thyroid hormone-induced changes in lipid and energy metabolism in the liver of Lithobates catesbeianus tadpoles.

BackgroundExposure of the American bullfrog Lithobates catesbeianus tadpoles to low temperature affects many biological processes including lipid metabolism and the thyroid hormone (TH) signaling pathway, resulting in arrest of TH-induced metamorphosis. To clarify what molecular events occur in this phenomenon, we investigated the glycerophospholipid and fatty acid (FA) compositions, the activities of mitochondrial enzymes and the transcript levels of related genes in the liver of control (26 °C) and cold-treated (4 °C) tadpoles with or without 5 nM 3,3′,5-triiodothyronine (T3).ResultsExposure to T3 decreased the tail height and polyunsaturation of FAs in the glycerophospholipids, and increased plasma glucose levels and transcript levels of primary TH-response genes including TH receptor, and some energy metabolic (cox4, srebp1 and fas) and FA chain elongase genes (elovl3 and elovl5). However, these T3-induced responses were abolished at 4 °C. Exposure to cold temperature enhanced plasma glucose, triglyceride and free FA levels, monounsaturation of FAs, mitochondrial enzymes activities (cytochrome c oxidase and carnitine palmitoyltransferase; U/g liver), with the upregulation of the genes involved in glycogenolysis (pygl), gluconeogenesis (pck1 and g6pc2), FA β-oxidation (acadl), and cholesterol uptake and synthesis (hmgcr, srebp2 and ldlr1), glycerophospholipids synthesis (pcyt1, pcyt2, pemt, and pparg), and FA monounsaturation (scd1) and chain elongation (elovl1 and elovl2). T3 had little effect on the cold-induced changes.ConclusionsOur study demonstrated that exposures to T3 and cold temperature exert different effects on lipid metabolism, resulting in changes in the FA composition in glycerophospholipids, and suggests that a cold-induced signal may block TH-signaling pathway around primary TH-response genes.Electronic supplementary materialThe online version of this article (doi:10.1186/s13578-016-0087-5) contains supplementary material, which is available to authorized users.

Pancreatic α-Cells and Insulin-Deficient Diabetes

Glucagon plays a major role in glucose homeostasis. This pancreatic hormone acts primarily on the liver activating gluconeogenesis and glycogenolysis, which promote hepatic glucose output, and increases plasma glucose levels (1, 2). Although glucagon secretion by pancreatic -cells is inhibited at high glucose concentrations, this process is augmented at low glucose levels (3). In this manner, glucagon release is one of the main lines of defense against hypoglycemia (4, 5). The complementary function of glucagon and insulin and their different regulation by nutrients and other control signals allow for the maintenance of plasma glucose levels within physiological ranges. Furthermore, glucagon stimulates hepatic fatty acid oxidation and ketogenesis, regulates food intake by central actions, increases adipose tissue thermogenesis and opposes to several insulin actions (2, 6). In addition to its role in glucose homeostasis, a growing body of evidence indicates that glucagon is also involved in the pathophysiology of diabetes and some of its complications. Hyperglucagonemia, either absolute or relative to plasma insulin levels, has been related with increased hepatic glucose output in type 1 diabetes (T1D), which aggravates hyperglycemia. Despite the high plasma glucose levels present in diabetic individuals, glucagon secretion is not suppressed (4). In this regard, several therapeutic designs involve the decrease of glucagon secretion from pancreatic -cells and/or the attenuation of glucagon actions on peripheral tissues (7). With the progression of T1D, the ability of pancreatic -cells to respond to hypoglycemia becomes impaired, leading to defective counterregulation to falling plasma glucose levels (4, 5). This is a life-threatening situation, particularly in those diabetic patients subjected to insulin treatment (iatrogenic hypoglycemia) (8). All these functional defects in glucagon secretion in T1D have been related with the lack of intraislet insulin signaling in pancreatic -cells, intrinsic -cell glucose-sensing defects, and/or altered neural regulation of glucagon release (2, 8). However, the specific nature of these functional defects is still not well defined. The dynamics of the pancreatic -cell mass also seems to play an important role to maintain absolute or relative hyperglucagonemia in diabetes. Although T1D leads to specific immunological attack and destruction of pancreatic -cells, which results in decreased -cell mass, -cell mass has been reported to be invariable or slightly increased in different models of autoimmune and insulin-deficient diabetes (9–11). This survival ability of pancreatic -cells in a T1D environment may be probably related with their better autonomous immune responses (12) and survival gene networks (13) compared with -cells. Despite the importance of pancreatic -cells and glucagon secretion in glucose homeostasis and diabetes, the research about the physiology of this islet population has been neglected for a long time. In part, this minor attention has been due to the central role of pancreatic -cells in the pathogenesis of diabetes, which has been the focus of most islet biology research. The study on -cells was also hampered because of the lack of physiological identification patterns to recognize this islet cell type. Additionally, the number of pancreatic -cells within the islet are scarce in rodents (15%–20% of total cells), the main animal models used in diabetology (14). All these factors, together with the difficulties to separate from non-cells in enriched samples as well as limitations of conventional techniques, have been a further restriction for a deeper exploration of this islet cell type. However, since the nineties, numerous technical advances have allowed to overcome these problems and to undertake in depth studies on the regulation

Productive and reproductive performance of rabbits does as affected by bee pollen and/or propolis, inulin and/or mannan-oligosaccharides

&lt;p&gt;The aim of the paper was to compare the effect of prebiotics (inulin and/or mannan-oligosaccharides, MOS) and bee products (bee pollen and/or propolis) on productive and reproductive performance of rabbit does. Seventy nulliparous V-line female rabbits were distributed among 7 groups. The groups were fed the same diet and received no supplements (control group), natural molecules (bee pollen and/or propolis) at 200 mg/kg body weight (BW) or prebiotics (inulin and/or MOS) at 35 mg/kg BW. Productive, reproductive, biochemical and haematological traits were investigated. Bee pollen with propolis significantly increased body weight gain of does 1 wk after mating (3.53%), decreased feed intake (4.49%) and caused larger litter size (39.4%), heavier body weight of litter (17.7%), a greater number of kits born alive (48.7%), higher weight of kits (87.81%) at 28 d of age, higher milk yield (43.6%) and more favourable milk conversion ratio (31.6%). Moreover, bee pollen with propolis had significantly increased plasma total protein (43.1%), albumin (45.7%), globulin (41.0) and progesterone (60.5%), and had a significantly decreased plasma cholesterol (31.1%), aspartate aminotransferase/alanine aminotransferase ratio (20.3%) compared to the control group. Does treated with growth promoters had significantly fewer services per conception (22%) and greater fertility rate (21%) compared to the control group. Inulin with or without MOS significantly increased plasma glucose (49.9 and 50%, respectively) and feed cost (90.2%) compared to the control group. Supplementation of MOS or bee pollen with or without propolis had significantly greater relative economic efficiency (61.9, 55.1 and 27.1%, respectively) than the control group. MOS and bee pollen with or without propolis are able to improve productive and reproductive performance and economic efficiency of rabbit does in comparison to the unsupplemented group.&lt;/p&gt;

Short communication: Production performance and plasma metabolites of dairy ewes in early lactation as affected by chitosan

The objective of this study was to evaluate the effects of chitosan (CHI) supplementation on production performance and blood parameters in dairy ewes. Twenty-four multiparous Latxa dairy ewes at d 16 of lactation were divided into two groups of 12 ewes each. Ewes were fed one of two experimental concentrates (0.840 kg dry matter/d), control or supplemented with 1.2% CHI, on a dry matter basis. Ewes also had free access to tall fescue hay, water, and mineral salts. The experimental period lasted for 25 d, of which the first 14 d were for treatment adaptation and the last 11 d for measurements and samplings. Supplementation with CHI decreased total (p=0.043) and fescue (p=0.035) dry matter intake (DMI), but did not affect concentrate DMI. Supplementation with CHI, moreover, increased plasma glucose (p=0.013) and BUN concentrations (p=0.035), but did not affect those of non-esterified fatty acids. Dietary supplementation with CHI, however, did not affect milk yield, 6.5% FCM, milk composition, or BW, but it improved dietary apparent efficiency by increasing the milk yield-to-DMI (p=0.055) and 6.5% FCM-to-DMI (p=0.045) ratios. In conclusion, dietary supplementation of chitosan maintained ewe performance while reducing feed intake and improving dietary apparent efficiency.

Glucose and fatty acid metabolism in infarcted heart from streptozotocin-induced diabetic rats after 2weeks of tissue remodeling.

BackgroundThe effects of streptozotocin (STZ)-induced diabetes on heart metabolism and function after myocardial infarction (MI) remodelling were investigated in rats.MethodsFifteen days after STZ (50 mg/kg b.w. i.v.) injection, MI was induced by surgical occlusion of the left coronary artery. Two weeks after MI induction, contents of glycogen, ATP, free fatty acids and triacylglycerols (TG) and enzyme activities of glycolysis and Krebs cycle (hexokinase, glucose-6-phosphate dehydrogenase, phosphofructokinase, citrate synthase) and expression of carnitine palmitoyl-CoA transferase I (a key enzyme of mitochondrial fatty acid oxidation) were measured in the left ventricle (LV). Plasma glucose, free fatty acids and triacylglycerol levels were determined. Ejection fraction (EF) and shortening fraction (SF) were also measured by echocardiography.ResultsGlycogen and TG contents were increased (p < 0.05) whereas ATP content was decreased in the LV of the non-infarcted diabetic group when compared to the control group (p < 0.05). When compared to infarcted control rats (MI), the diabetic infarcted rats (DI) showed (p < 0.05): increased plasma glucose and TG levels, elevated free fatty acid levels and increased activity of, citrate synthase and decreased ATP levels in the LV. Infarct size was smaller in the DI group when compared to MI rats (p < 0.05), and this was associated with higher EF and SF (p < 0.05).ConclusionsSystolic function was preserved or recovered more efficiently in the heart from diabetic rats two weeks after MI, possibly due to the high provision of glucose and free fatty acids from both plasma and heart glycogen and triacylglycerol stores.

Hot topic: Early postpartum treatment of commercial dairy cows with nonsteroidal antiinflammatory drugs increases whole-lactation milk yield

Previous research has shown that postpartum administration of the nonsteroidal antiinflammatory drug (NSAID) sodium salicylate can increase 305-d milk yield in older dairy cattle (parity 3 and greater). However, in this prior work, sodium salicylate was delivered to cows via the drinking water, a method that does not align well with current grouping strategies on commercial dairy farms. The objective of the current study was to replicate these results on a commercial dairy farm with a simplified treatment protocol and to compare sodium salicylate with another NSAID, meloxicam. Dairy cattle in their second lactation and greater (n=51/treatment) were alternately assigned to 1 of 3 treatments at parturition, with treatments lasting for 3d. Experimental treatments began 12 to 36h after parturition and were (1) 1 placebo bolus on the first day and 3 consecutive daily drenches of sodium salicylate (125g/cow per day; SAL); (2) 1 bolus of meloxicam (675mg/cow) and 3 drenches of an equal volume of water (MEL); or (3) 1 placebo bolus and 3 drenches of water (CON). Blood samples were collected on the first day of treatment, immediately following the last day of treatment, and 7d after the last day of treatment; plasma was analyzed for glucose, β-hydroxybutyrate (BHB), free fatty acids, haptoglobin, and paraoxonase. Milk production, body condition score, reproductive status, and retention in the herd were monitored for 365d posttreatment, and effects of treatment, parity, days in milk, and interactions were evaluated in mixed effects models. Significance was declared at P<0.05. Whole-lactation milk and protein yields were greater in NSAID-treated cows, although 305-d fat production was not affected. There was a significant interaction of treatment and parity for plasma glucose concentration; MEL increased plasma glucose concentrations compared with CON and SAL in older cows. Sodium salicylate decreased plasma BHB concentration compared with MEL at 7d posttreatment, although no difference was detected immediately following treatment. Haptoglobin concentrations were elevated in SAL cows compared with CON. There was a tendency for CON cows to be removed from the herd more quickly than MEL cows (42 vs. 26% at 365d posttreatment). Body condition score, concentrations of plasma free fatty acids and paraoxonase, and time to pregnancy were not affected by treatment. These results indicate that NSAID administration in postpartum cows has the potential to be a viable way to improve productivity and potentially longevity in commercial dairies, although further research is necessary to optimize recommendations for producers.

Antiparasitic activity of the essential oil of Lippia alba on ectoparasites of Colossoma macropomum (tambaqui) and its physiological and histopathological effects

This study investigated the in vivo and in vitro antiparasitic effects of the essential oil of Lippia alba and the blood-related and histopathological alterations that it causes in Colossoma macropomum. In the in vitro trial, the anthelminthic effects of 160, 320, 640, 1280 and 2560mg/L of the essential oil were tested against monogenoideans (Anacanthorus spathulatus, Notozothecium janauachensis and Mymarothecium boegeri) of the gills of this fish, which are its natural parasites. The concentrations of 1280mg/L and 2560mg/L showed 100% efficacy after 20min of exposure to the essential oil, while at lower concentrations this efficacy against the gill monogenoideans only occurred after 2–3h of in vitro exposure. However, in the controls, mortality of all of these monogenoideans only occurred after 9h. A total of 240 fry were distributed into four treatments (20 fish per repetition) and three repetitions were used in the in vivo trial for baths with 100 and 150mg/L of the essential oil of L. alba, for 30min. The efficacy in this trial against Ichthyophthirius multifiliis in fish exposed to 100 and 150mg/L of the essential oil was 40.7% and 50.3%, respectively. However, for monogenoideans, there was efficacy of 14.0% only in the fish exposed to 100mg/L of the essential oil used. Moreover, the fish exposed to these concentrations of the essential oil presented increased plasma glucose levels, thus denoting signs of stress. Severe lesions such as hyperplasia, fusion of the lamellar epithelium, capillary dilatation, epithelial detachment, lamellar aneurysm, epithelial rupture with hemorrhage, congestion, edema, necrosis, mucous cell proliferation, chloride cells and lamellar hypertrophy were observed in the gills of the fish exposed to 100 and 150mg/L of the essential oil of L. alba. Alterations to total protein levels, hemoglobin, hematocrit, red blood cell number, thrombocytes number, white blood cell number, lymphocytes, eosinophils and blood neutrophil number was also observed in these fish. The essential oil of L. alba showed great potential for antiparasitic treatment, given that it had high in vitro efficacy against monogenoideans and in vivo efficacy against the protozoon I. multifiliis. Because of the low concentrations of the essential oil (100 and 150mg/L) that were tolerated by the fish and thus could be used in the therapeutic baths, the efficacy against monogenoideans was low. This indicates that there is a need for additional strategies for using this essential oil in antiparasitic treatments, since the concentrations that eliminate these ectoparasites are toxic for the hosts. Lastly, this was the first study on the antiparasitic activity of L. alba. Statement of RelevanceThe manuscript entitled “Antiparasitic activity of the essential oil of Lippia alba on ectoparasites of Colossoma macropomum (tambaqui) and its physiological and histopathological effects”, represents original article on use of the essential oil of Lippia alba on ectoparasites of tambaqui, an important finfish of Amazon region. This manuscript includes treatment in vitro against monogeneans, and in vivo against protozoans and monogeneans, besides histopathological and hematological features of the fish exposed to different concentrations of L. alba, a medical plant from South and Central America.

Effects of central gastrin-releasing peptide on glucose metabolism

Gastrin–releasing peptide (GRP) mediated signals in the central nervous system (CNS) influence many functions associated with energy metabolism. The purpose of the present study was to investigate the central effect of GRP on glucose metabolism in the male rat. Intracerebroventricular (icv) administration of GRP caused an immediate hyperglycaemia which was sustained till the end of the infusion. The rise in plasma glucose levels was accompanied by an increase in endogenous glucose production (EGP), as well as increases in plasma glucagon and insulin concentrations. Furthermore, no differences in plasma corticosterone levels were noted between control and GRP treated rats. These results demonstrate that central GRP increases plasma glucose levels, probably by stimulating pancreatic glucagon release and concomitantly or subsequently endogenous glucose production.

The post feeding glycaemic and insulin response to copra meal in horses

Knowing the effect a feed ingredient has on post-feeding glycaemic and insulin responses is important when managing conditions like equine metabolic syndrome, laminitis and the polysaccharide storage myopathy form of tying up in horses. Feeds that cause minimal post-feeding disturbances to plasma glucose and insulin are desirable. This study was conducted to determine the post feeding glycaemic and insulin response in horses to copra meal (Copra Meal; 11% non-structural carbohydrate; NSC) and to compare this to the responses observed to low NSC pasture (Pasture; 7% NSC) and higher NSC extruded pellet (Pellet; 25.3% NSC) and sweetfeed (Sweetfeed; 33.7% NSC) rations.Copra Meal did not increase plasma glucose levels above those observed in horses grazing the low NSC Pasture while the Pellet and Sweetfeed rations caused significant post-feeding rises in plasma glucose. The Pellet and Sweetfeed rations also raised post feeding plasma insulin levels significantly compared to Pasture and Copra Meal. Copra Meal raised plasma insulin levels significantly higher than that observed in horses grazing Pasture from 15 to 60min post feeding, after which time there was no significant difference. The results of this study demonstrated that the NSC content of a feed ingredient will influence the post-feeding glycaemic and insulin response to that feed, with low NSC feeds giving significantly lower responses than higher NSC feeds. The insulin response to Copra Meal observed in this study was small both in magnitude and time in comparison to levels reported in the literature needed to induce laminitis and as such are unlikely to be physiologically significant. Copra Meal is a feed ingredient that could be considered for use in diets for horses needing to remain on a low NSC diet that will cause minimal disturbance to their post feeding glucose and insulin levels.

Mean platelet volume: An economical diagnostic marker of cardiovascular risk assessment in altered fasting blood glucose levels

Background: Platelets with altered morphology or large size are more thrombogenic and are likely to be associated with increased risk of vascular disease. Platelet parameters especially high mean platelet volume (MPV) has been reported in diabetic patients as major contributing factor. The aim of the present study was to find correlation between fasting blood glucose value and hematological variables (PC and MPV), not only in diabetics, but also in the normoglycemic subjects and patients with impaired fasting blood glucose levels.Materials and Methods: In the present study 3471 subjects were analyzed retrospectively and categorized into three groups based on the fasting blood glucose levels as Group I - normoglycemics (FBG ? 109 mg/dl, n = 1158), Group II- impaired fasting blood glucose (FBG ? 126 mg/dl, n = 1158) and Group III – Diabetics (FBG ? 127 mg/dl, n = 1155).Results: We found progressive increase in value of MPV with the increasing FBG levels, in the following order: G1 (8.44 ± 0.842 fl), G2 (8.98 ± 0.898 fl), G3 (9.31 ± 0.967 fl). The platelet count however, did not show much statistical significance with rising glucose levels.Conclusions: MPV increased proportionally with increasing plasma glucose levels. Although the variation between the normoglycemics and impaired fasting group was not very significant, the parameters still showed progressive increase with rising sugar levels significant in diabetic group.Asian Journal of Medical Sciences Vol.7(1) 2015 30-33

Experimental hyperlipidemia induces insulin resistance in sheep

This study aimed to evaluate the effects of intravenous infusion of a soybean-based lipid emulsion on some blood energy–related metabolites and insulin sensitivity indexes in sheep. Four clinically healthy ewes were assigned into a 2-treatment, 2-period cross-over design. Either normal saline (NS) or lipid emulsion (LE) was intravenously introduced at a rate of 0.025 mL·kg−1 min−1 for 6 h. The concentrations of blood nonesterified fatty acid (NEFA), beta-hydroxybutyrate, triglyceride, cholesterol, urea, creatinine, cortisol, glucose, and insulin were measured at different time points. After 6 h, intravenous glucose tolerance test was performed. Lipid infusion elicited an increase (P < 0.05) in the NEFA, beta-hydroxybutyrate, and triglyceride concentrations compared with the baseline value and NS infusion. Infusion of NS did not influence blood glucose concentration; however, LE infusion increased plasma glucose concentration (P < 0.05). At time point 12 h, serum insulin concentrations were increased (P < 0.05) in NS treatment; however, such an increase was not observed in the LE treatment. Insulin sensitivity index for the LE infusion was lower (P < 0.05) than that for the NS treatment. The glucose effectiveness was not (P > 0.05) different among treatments. In the LE treatment, acute-phase insulin responses increased (P < 0.05) and disposition index decreased (P < 0.001) compared with NS treatment. The results showed that experimentally induced NEFA in blood could cause insulin resistance in sheep. The current model could be used to evaluate the pathogenesis of conditions associated with increased lipid mobilization and insulin resistance.

Evaluation of propylene glycol and glycerol infusions as treatments for ketosis in dairy cows

To evaluate propylene glycol (PG) and glycerol (G) as potential treatments for ketosis, we conducted 2 experiments lasting 4 d each in which cows received one bolus infusion per day. Blood was collected before infusion, over 240min postinfusion, as well as 24 h postinfusion. Experiment 1 used 6 ruminally cannulated cows (26±7 d in milk) randomly assigned to 300-mL infusions of PG or G (both ≥99.5% pure) in a crossover design experiment with 2 periods. Within each period, cows were assigned randomly to infusion site sequence: abomasum (A)-cranial reticulorumen (R) or the reverse, R-A. Glucose precursors were infused into the R to simulate drenching and the A to prevent metabolism by ruminal microbes. Glycerol infused in the A increased plasma glucose concentration the most (15.8mg/dL), followed by PG infused in the R (12.6mg/dL), PG infused in the A (9.11mg/dL), and G infused in the R (7.3mg/dL). Infusion of PG into the R increased plasma insulin and insulin area under the curve (AUC) the most compared with all other treatments (7.88 vs. 2.13μIU/mL and 321 vs. 31.9min×μIU/mL, respectively). Overall, PG decreased plasma BHBA concentration after infusion (−6.46 vs. −4.55mg/dL) and increased BHBA AUC (−1,055 vs. −558min ×mg/dL) compared with G. Plasma NEFA responses were not different among treatments. Experiment 2 used 8 ruminally cannulated cows (22±5 d in milk) randomly assigned to treatment sequence in a Latin square design experiment balanced for carryover effects. Treatments were 300mL of PG, 300mL of G, 600mL of G (2G), and 300mL of PG + 300mL of G (GPG), all infused into the R. Treatment contrasts compared PG with each treatment containing glycerol (G, 2G, and GPG). Propylene glycol increased plasma glucose (14.0 vs. 5.35mg/dL) and insulin (7.59 vs. 1.11μIU/mL) concentrations compared with G, but only tended to increase glucose and insulin concentrations compared with 2G. Propylene glycol increased AUC for glucose (1,444 vs. 94.3mg/dL) and insulin (326 vs. 6.58min×μIU/mL) compared with G, and tended to increase insulin AUC compared with 2G. Propylene glycol was not different from GPG for glucose, insulin, or BHBA responses. Propylene glycol decreased plasma BHBA concentration (−10.3 vs. −4.21mg/dL) and increased BHBA AUC (−1,578 vs. −1.42min ×mg/dL) compared with G, but not compared with 2G. In general, and compared with G, GPG decreased plasma NEFA concentrations after infusions and PG decreased plasma NEFA concentrations early but not late after infusions. We conclude that a 300-mL dose of PG is more effective at increasing plasma glucose concentration than G and at least as effective as 600mL of G or a combination of G and PG when administered in the cranial reticulorumen.

Wczesne markery miażdżycy u chorych z nieprawidłową glikemią na czczo

Introduction. It is known that increased plasma glucose, which includes impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and diabetes, is a risk factor for atherosclerosis. Individuals with IFG exhibit a higher rate of cardiovascular events compared with those with normal fasting glucose. The aim of the study was to evaluate whether IFG has an influence on early markers of atherosclerosis [intima media thickness (IMT), strain (S, deformation of the vessels wall), and strain rate (Sr, deformation over time)] in common ca­rotid artery (CCA) compare to healthy subjects (without disturbances of glucose metabolism). Patients and methods. A group of 25 dysglycemic patients with IFG and 15 healthy subjects of similar age and gender were examined. Blood analyses and anthropometric measurement [systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR)] were obtained. Carotid IMT, S, and Sr were measured by tissue Doppler. IFP was diagnosed according to the diagnostic criteria for IFG in Poland. Results. Patients with IFG had higher DBP and IMT of CCA (right and left) compared with control. There was no difference in SBP and HR between patients with IFG and controls. Strain of CCA was decreased in subject with IFG compared with controls and strain rate of CCA was increased in patients with IFG compared with the controls. Conclusion. IFG may have an influence on early markers of atherosclerosis, but further investigations are needed to confirm these observations.

Osmoregulatory adaptations of freshwater air-breathing snakehead fish (Channa striata) after exposure to brackish water.

NaCl-rich rock salt dissolved in natural water source leads to salinity fluctuation that profoundly affects freshwater ecosystem and aquatic fauna. The snakehead (Channa striata) can live in saline water, but the osmoregulatory mechanisms underlying this ability remain unclear. Herein, we found that exposure to salinities ≥ 10‰ NaCl markedly elevated plasma cortisol and glucose levels, and caused muscle dehydration. In a study of time-dependent response after being transferred from fresh water (0‰ NaCl, FW) to salt-dissolved brackish water (10‰ NaCl, SW), FW-SW, cortisol increased rapidly along with elevations of plasma glucose and lactate. Interestingly, plasma cortisol returned to baseline after prolonged exposure, followed by a second peak that probably enhanced the branchial Na(+)/K(+)-ATPase activity. Under SW-FW condition, Na(+)/K(+)-ATPase activity was not altered as compared to SW-adapted fish. In conclusion, salinity change, especially FW-SW, induced a stress response and hence cortisol release in C. striata, which might increase plasma glucose and lactate to energize the branchial Na(+)/K(+)-ATPase.