Studies on the Blood Glucose Level in Channa punctatus (Bloch.)

The normal blood glucose level of Channa punctatus undergoes a seasonal change. A post-spawning hyperglycemia is found during August, September, October and November. Fish kept out of water show increase in blood glucose level upto 24 hours. When returned to water, the asphyxial hyperglycemia subsides after 24 hours. Starvation does not appear to affect the blood glucose in this fish.     

应激性高血糖与急性自发性脑出血患者术后并发症和早期预后的相关性研究

目的:探讨应激性高血糖与自发性脑出血患者术后并发症及早期预后的关系。方法:回顾性分析我院收治的自发性脑出血患者358例,根据入院时血糖水平、糖化血红蛋白(HbAlc)及既往有无糖尿病史分为血糖正常组(96例)、应激性高血糖组(107例)及糖尿病组(155例),记录和比较各组入院时的血糖、格拉斯哥昏迷评分(GCS)、平均出血量及入院后30 d时各组的术后并发症发生情况、格拉斯哥预后评分(GOS)的差异。结果:糖尿病组入院时血糖水平、平均出血量、重型患者所占比率、脑出血破入脑室、颅内再出血、颅内感染、肺部感染、尿路感染及上消化道出血发生率、GOS分级植物状态或死亡发生率均明显高于应激性高血糖组(P0.05),GOS分级良好率低于应激性高血糖组(P0.05);而应激性高血糖组入院时血糖水平、平均出血量、重型患者所占比率、脑出血破入脑室、颅内再出血发生率、GOS分级植物状态或死亡发生率均明显高于血糖正常组(P0.05)。结论:自发性脑出血患者入院时应激性高血糖与患者的病情显著相关,可加重急性脑出血的不良预后。     

Flight is the key to postprandial blood glucose balance in the fruit bats Eonycteris spelaea and Cynopterus sphinx

Excessive sugar consumption could lead to high blood glucose levels that are harmful to mammalian health and life. Despite consuming large amounts of sugar‐rich food, fruit bats have a longer lifespan, raising the question of how these bats overcome potential hyperglycemia. We investigated the change of blood glucose level in nectar‐feeding bats (Eonycteris spelaea) and fruit‐eating bats (Cynopterus sphinx) via adjusting their sugar intake and time of flight. We found that the maximum blood glucose level of C. sphinx was higher than 24 mmol/L that is considered to be pathological in other mammals. After C. sphinx bats spent approximately 75% of their time to fly, their blood glucose levels dropped markedly, and the blood glucose of E. spelaea fell to the fast levels after they spent 70% time of fly. Thus, the level of blood glucose elevated with the quantity of sugar intake but declined with the time of flight. Our results indicate that high‐intensive flight is a key regulator for blood glucose homeostasis during foraging. High‐intensive flight may confer benefits to the fruit bats in foraging success and behavioral interactions and increases the efficiency of pollen and seed disposal mediated by bats.     

Effect of streptozotocin on the blood glucose level and histology of the principal islets of Channa punctatus (Bloch).

The effect of streptozotocin, an antibiotic and diabetogenic drug, has been studied on the blood glucose level and islet histology of a freshwater fish, Channa punctatus. The drug elicits a triphasic response in the blood glucose level, comprising an initial hyperglycemia followed by a transient fall, and restitution of normal values 3...4 days after the treatment. Significant degenerative changes occur in the islet beta cells. Severity of the beta cell damage is dose dependent and the drug has been found to be beta-cytotoxic to a considerable extent. Unlike mammals, Channa punctatus does not become diabetic following the streptozotocin administration, at doses varying 200-400 mg/kg b.wqnd over a period of 96 hours post-injection.     

Glucose intolerance in teleost fish: fact or fiction?

Teleost fish are generally considered to be glucose intolerant. This mini-review examines some of the background and the possible mechanistic bases for this statement. Glucose intolerance is a clinical mammalian term meaning that a glucose load results in persistent hyperglycemia. Teleost fish show persistent hyperglycemia that is generally coincident with transient hyperinsulinemia. The fact that teleost generally have high plasma insulin compared with mammals implies insulin-deficiency is not a suitable explanation for this persistent hyperglycemia. Instead, peripheral utilization of glucose is probably the principle cause of hyperglycemia. Recent evidence for muscle insulin receptors, glucose transporters and hexokinase/glucokinase is reviewed and future experimental directions are suggested. If by altering peripheral glucose utilization fish could become more glucose tolerant, costs to the aquaculture industry may be substantially reduced.     

Scanning electron microscopic analysis of intramyocellular lipid droplets in an animal model of type 2 diabetes

Objective: To evaluate the accumulation pattern of intramyocellular lipids (IMCLs) in striated muscle during the development and progression of diabetes, using a novel scanning electron microscopic method. Methods and Procedures: Hyperglycemia was induced by feeding diabetes‐prone (DP) Psammomys obesus a high‐energy (HE) diet. Lipid accumulation within gastrocnemius muscle fibers was assessed in formalin‐fixed muscle samples during the development of hyperglycemia using high resolution imaging in a scanning electron microscope. We evaluated the temporal relationship between changes in IMCL quantity and morphology and the altered glucose metabolism and assessed the effect of reversal of hyperglycemia on IMCL level and morphology. Diabetes‐resistant (DR) P. obesus served as controls. Results: Lipid accumulation in the muscle fibers of DP animals was increased with the development of hyperglycemia. This was characterized by increased lipid density as well as by an abundance of large lipid droplets. Reversal of the phenotype resulted in the disappearance of large lipid droplets. The IMCL level and the distribution of lipid droplet size were similar in muscles of both the normoglycemic DR and DP animals, with an abundance of small lipid droplets. This profile was changed following a HE diet only in the DP animals. Discussion: Lipid accumulation in the muscle of P. obesus during the development of hyperglycemia is characterized by increased quantity and accumulation of large lipid droplets. These changes were reversible upon normalization of blood glucose. The evaluated methodology is a useful tool for the study of the dynamics of lipid accumulation in different metabolic conditions.     

Taurine Alters Respiratory Gas Exchange and Nutrient Metabolism in Type 2 Diabetic Rats

Objective: To assess the effect of taurine supplementation on respiratory gas exchange, which might reflect the improved metabolism of glucose and/or lipid in the type 2 diabetic Otsuka Long‐Evans Tokushima Fatty (OLETF) rats. Research Methods and Procedures: Male OLETF rats (16 weeks of age) were randomly divided into two groups: unsupplemented group and taurine‐supplemented (3% in drinking water) group. After 9 weeks of treatment, indirect calorimetry and insulin tolerance tests were conducted. The amounts of visceral fat pads, tissue glycogen, the blood concentrations of glucose, triacylglycerol, taurine, and electrolytes, and the level of hematocrit were compared between groups. A nondiabetic rat strain (Long‐Evans Tokushima Otsuka) was used as the age‐matched normal control. Results: The indirect calorimetry showed that the treatment of OLETF rats with taurine could reduce a part of postprandial glucose oxidation possibly responsible for the increase of triacylglycerol synthesis in the body. Taurine supplementation also improved hyperglycemia and insulin resistance and increased muscle glycogen content in the OLETF rats. Supplementation with taurine increased the blood concentration of taurine and electrolyte and fluid volume, all of which were considered to be related to the improvement of metabolic disturbance in OLETF rats. Discussion: Taurine supplementation may be an effective treatment for glucose intolerance and fat/lipid accumulation observed in type 2 diabetes associated with obesity. These metabolic changes might be ascribed, in part, to the alteration of circulating blood profiles, where the improved hyperglycemia and/or the blood accumulation of taurine itself would play roles.     

Induction of hyperglycemia in adult intrauterine growth-restricted rats: effects on renal function

Intrauterine growth restriction (IUGR) leads to a reduction in nephron endowment at birth and is linked to renal dysfunction in adulthood. The aim of the present study was to determine whether kidneys of IUGR rat offspring are more vulnerable to a secondary insult of hyperglycemia. IUGR was induced in Wistar-Kyoto rats by maternal protein restriction. At 24 wk of age, diabetes was induced in male IUGR and non-IUGR offspring by streptozotocin injection; insulin was injected daily to maintain blood glucose levels at either a mild (7-10 mmol/l; n=8/group) or a moderate (10-15 mmol/l; n=8/group) level. At 32 wk of age, renal function was assessed using ultrasound and [(3)H]inulin and [(14)C]para-aminohippurate clearance techniques. Conscious mean arterial blood pressure and heart rate were unchanged in IUGR offspring. Relative kidney length was increased significantly in IUGR offspring, and renal function was altered significantly; of importance, there was a significant increase in filtration fraction, indicative of glomerular hyperfiltration. Induction of hyperglycemia led to marked impairment of renal function. However, the response to hyperglycemia was not different between IUGR and non-IUGR offspring. Maintaining blood glucose levels at a mild hyperglycemic level led to marked improvement in all measures of renal function in IUGR and non-IUGR offspring. In conclusion, while the IUGR offspring showed evidence of hyperfiltration, the response to hyperglycemia was similar in IUGR and non-IUGR kidneys in adulthood. Importantly, maintaining blood glucose levels at a mild hyperglycemic level markedly attenuated the renal dysfunction associated with diabetes, even in IUGR offspring.     

Decreased cerebral blood flow and hemodynamic parameters during acute hyperglycemia in mice model observed by dual‐wavelength speckle imaging

In this study, we use dual‐wavelength optical imaging‐based laser speckle technique to assess cerebral blood flow and metabolic parameters in a mouse model of acute hyperglycemia (high blood glucose). The effect of acute glucose levels on physiological processes has been extensively described in multiple organ systems such as retina, kidney, and others. We postulated that hyperglycemia also alters brain function, which in turn can be monitored optically using dual‐wavelength laser speckle imaging (DW‐LSI) platform. DW‐LSI is a wide‐field, noncontact optical imaging modality that integrates the principles of laser flowmetry and oximetry to obtain macroscopic information such as hemoglobin concentration and blood flow. A total of eight mice (C57/BL6) were used, randomized into two groups of normoglycemia (control, n = 3) and hyperglycemia (n = 5). Hyperglycemia was induced by intraperitoneal injection of a commonly used anesthetic drug combining ketamine and xylazine (KX combo). We found that this KX combo increases blood glucose (BG) levels from 150 to 350 mg/dL, approximately, when measured 18 minutes post‐administration. BG continues to increase throughout the test period, with BG reaching an average of 463 ± 20.34 mg/dL within 60 minutes. BG levels were measured every 10 minutes from tail blood using commercially available glucometer. Experimental results demonstrated reductions in cerebral blood flow (CBF) by 55%, tissue oxygen saturation (SO₂) by 15%, and cerebral metabolic rate of oxygen (CMRO₂) by 75% following acute hyperglycemia. The observed decrease in these parameters was consistent with results reported in the literature, measured by a variety of experimental techniques. Measurements with laser Doppler flowmetry (LDF) were also performed which confirmed a reduction in CBF following acute hyperglycemia. In summary, our findings indicate that acute hyperglycemia modified brain hemodynamic response and induced significant changes in blood flow and metabolism. As far as we are aware, the implementation of the DW‐LSI to monitor brain hemodynamic and metabolic response to acute hyperglycemia in intact mouse brain has not been previously reported.      

Dammarane-type triterpene extracts of Panax notoginseng root ameliorates hyperglycemia and insulin sensitivity by enhancing glucose uptake in skeletal muscle

Skeletal muscle is an important organ for controlling the development of type 2 diabetes. We discovered Panax notoginseng roots as a candidate to improve hyperglycemia through in vitro muscle cells screening test. Saponins are considered as the active ingredients of ginseng. However, in the body, saponins are converted to dammarane-type triterpenes, which may account for the anti-hyperglycemic activity. We developed a method for producing a dammarane-type triterpene extract (DTE) from Panax notoginseng roots and investigated the extract’s potential anti-hyperglycemic activity. We found that DTE had stronger suppressive activity on blood glucose levels than the saponin extract (SE) did in KK-A^y mice. Additionally, DTE improved oral glucose tolerance, insulin sensitivity, glucose uptake, and Akt phosphorylation in skeletal muscle. These results suggest that DTE is a promising agent for controlling hyperglycemia by enhancing glucose uptake in skeletal muscle.     

Effect of corticoliberin fragment CRF4-6 on blood glucose level and body temperature of rats

The effects of tripeptide corticoliberin fragment CRF4-6 (Pro-Pro-Ile) on blood glucose level and the rat body temperatire were investigated. Intracerebroventricularly injected CRF4-6 (6, 30, 150 nmol/head) causes a dosedependent hyperglycemia and hyperthermia in anaesthetized animals. Corticotropin releasing factor antagonist alpha-helical CRF4-6 (6.5 nmol/head) abolishes the influence of tripeptide CRF4-6 (6 nmol/head) on blood glucose level and body temperature of rats. Bilateral adrenalectomy has no effect on tripeptide-induced hyperglycemia and hyperthemia. This result indicates that hyperglycemic and hyperthermal effects of tripeptide occur independently of adrenal gland catecholamines. In addition, non-pituitary corticoliberin receptors are involved in CRF4-6 influences on blood glucose level and body temperature.     

外源性胰岛素对斑马鱼血糖及其转运的影响

斑马鱼（Danio rerio）在糖负荷状态下表现出持续高血糖现象。与对照组（仅腹腔注射灭菌去离子水）相比,葡萄糖组（仅腹腔注射葡萄糖）血浆胰岛素水平无显著差异,胰岛素基因表达显著上调,肝胰脏葡萄糖转运蛋白（glucose transporters,GLUTs）基因表达无显著差异,说明斑马鱼自身胰岛素分泌不足和葡萄糖转运迟缓是导致其在糖负荷状态下持续高血糖的原因。为了观察外源性胰岛素对斑马鱼血糖及其在体内转运的影响,设计低（1.25 IU/kg）、中（12.5 IU/kg）、高（125 IU/kg）3个浓度的胰岛素,分别与葡萄糖溶液（0.1 g/mL）共注射斑马鱼并观察其血糖变化。结果表明,低剂量胰岛素能有效促进斑马鱼血糖的降低,且能直观反映糖负荷后血糖的变化情况,为最适注射浓度。此外,研究显示斑马鱼血糖变化不受性别影响。在胰岛素最适注射浓度下,与葡萄糖组相比,胰岛素组（葡萄糖与胰岛素共注射）可以显著减少斑马鱼血糖恢复到正常水平的时间,进一步分析发现,斑马鱼血浆胰岛素水平增加,肝胰脏葡萄糖转运蛋白基因表达显著上调,但胰岛素基因表达却被显著抑制。综上所述,胰岛素分泌不足和葡萄糖转运迟缓是造成斑马鱼持续高血糖的原因;外源性胰岛素能够促进糖负荷状态下斑马鱼血糖的降低,但是具有反馈抑制斑马鱼肝胰脏胰岛素基因表达的作用。     

Vascular Perfusion and Blood-Brain Glucose Transport in Acute and Chronic Hyperglycemia

We studied the effects of acute and streptozotocin-induced chronic hyperglycemia on regional brain blood flow and perfusion characteristics, and on the regional transport of glucose across the blood-brain barrier in awake rats. We found (1) a generalized decrease in regional brain blood flow in both acute and chronic hyperglycemia; (2) that chronic, but not acute, hyperglycemia is associated with a marked and diffuse decrease in brain L-glucose space; and (3) that chronic hyperglycemia does not alter blood-to-brain glucose transport. Taken together, these results suggest that in streptozotocin-induced chronic hyperglycemia, there is a reduction in the proportion of perfused brain capillaries and/or an alteration in brain endothelial membrane properties resulting in decreased noncarrier diffusion of glucose.     

Hematology and recovery response in jacundá, Crenicichla saxatilis (Linnaeus, 1758) after short‐term handling stress

The objective of this study was to evaluate the hematological response of ringtail pike cichlid ornamental fish (Crenicichla saxatilis) during the recovery period after short‐term stress. The fish were previously submitted to the stress of chasing, capture and air exposure. Assayed were 24 C. saxatilis (85.2 ± 61.6 g) in three groups of eight fish; after 0.5, 6 and 24 h recovery, blood samples were collected. The total erythrocyte, relative thrombocyte and differential leukocyte counts as well as total hemoglobin, hematocrit, glucose, total plasma protein and the red blood cells (RBC) indices of mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and MCH concentration (MCHC) were determined. Stress responses were observed after 0.5 h, although hyperglycemia remained constant during the experiment. Total lymphocyte and hemoglobin values decreased after 0.5 h in the recovery period. An increase of neutrophils and monocytosis was observed after 0.5 and 6 h, respectively. The MCHC remained stable until after 0.5 h, then varied from this time forward. MCV, MCH and erythrocyte numbers oscillated throughout the experiment. Intense stress was observed in the studied C. saxatilis, with most hematological variables not returning to their initial levels after 24 h.     

Genetic engineering of Lactococcus lactis to produce an amylase inhibitor for development of an anti-diabetes biodrug

Diabetes is known as a multifactorial disease. The treatment of diabetes is complicated due to its inherent pathophysiological factors related to the disease. One of the complications of diabetes is postprandial hyperglycemia. Glucosidase inhibitors, particularly ?-amylase inhibitors can help manage postprandial hyperglycemia. The low molecular weight inhibitor of ? -amylases called PAMI (peptide amylase inhibitor) inhibits the ? -amylase. In this study we cloned this amylase blocker PAMI in Lactococcus lactis. Using this Lactococcus lactis expressing the PAMI, we prepared yogurt and fed it to diabetic mice models. There was decrease in the blood glucose level after 20 days of oral administration of the yogurt. This product be used as a biodrug in maintaining the blood glucose level in diabetic patients.     

Investigation on the acute toxic effect of pyrethrum on the blood glucose and of glucose administration on the acute pyrethrum toxicity in Meriones hurrianae Jerdon (Rodentia).

The effect of different doses of pyrethrum on the blood glucose level and glucose tolerance in pytethrum-administered gerbils, were investigated. Pyrethrum produces hyperglycemia and lowers the glucose tolerance indicating an impairment in the uptake and utilization of glucose. The possible reasons for these effects are discussed.     

α-Glucosidase Inhibitory Activity of a 70% Methanol Extract from Ezoishige (Pelvetia babingtonii de Toni) and Its Effect on the Elevation of Blood Glucose Level in Rats

The 70% methanol extract from ezoishige (Pelvetia babingtonii de Toni) inhibited the rat-intestinal α-glucosidase, sucrase and maltase activities, with IC₅₀ values of 2.24 and 2.84 mg/ml. Sucrose was orally administered with or without the extract to rats at 1000 mg/kg. The postprandial elevation in the blood glucose level at 15 and 30 min after the administration of sucrose with the extract was significantly suppressed when compared with the control. These results suggest that the extract from ezoishige has potent α-glucosidase inhibitors and would be effective for suppressing postprandial hyperglycemia.     

Glycogenolytic effect of pancreastatin in the rat

Pancreastatin is a novel 49-amino acid peptide with a C-terminal glycine amide. The peptide was isolated from porcine pancreatic extracts and shows a structural similarity to chromogranin A. The effect of synthetic porcine pancreastatin on blood glucose levels and hepatic glycogen content was investigated in ratsin vivo. Pancreastatin (300 pmol/kg) produced a time-dependent decrease in glycogen content of liver and a slight hyperglycemia. Basal plasma insulin and glucagon levels were not modified by pancreastatin. We suggest that pancreastatin could play a biological role in the glucose metabolism through a glycogenolytic effect.     

Recovery of wild, juvenile brown trout from stress of flow reduction, electrofishing, handling and transfer from river to an indoor simulated stream channel

Stress in wild brown trout Salmo trutta was assessed by sampling blood and measuring the concentrations of plasma cortisol and blood glucose in fish collected by electrofishing and immediately anaesthetized with metomidate. In the River Nidelva, Trondheim, Norway, the resting blood plasma cortisol concentration in the juvenile (0 + year) brown trout was 52 ± 44 nM (mean ± s .d .) in December and 2·3 nM (detection limit) in January. The corresponding blood glucose values were 1·8 ± 0·9 and 1·2 ± 0·2 mM, respectively. After electrofishing, handling and transport to the artificial stream, plasma cortisol and blood glucose levels increased significantly in both experiments. A maximum plasma cortisol level of 239 ± 120 and 71 ± 32 nM and a maximum blood glucose level of 3·9 ± 0·9 and 3·0 ± 0·9 mM were measured in the December and January stream channel experiments after transport, respectively. After introduction to the artificial stream, the blood plasma cortisol level returned to resting values within 24 h in the January stream channel experiment. The blood glucose levels remained at a higher level compared to the reference group throughout the December experiment, while it returned to resting values after 24 h in the January stream channel experiment. The major difference between the December and January experiments was the temperature within the artificial stream, 15–17° C in December and 7–9° C in January. This may have influenced the blood glucose levels. After dewatering of the artificial streambed there was a significant increase in plasma cortisol both in the December and January experiments, and after 24 h the plasma cortisol returned to the resting level in the January experiment. The blood glucose also increased during dewatering, although not significantly.     

Augmentation of hepatic and renal oxidative stress and disrupted glucose homeostasis by monocrotophos in streptozotocin-induced diabetic rats

Several recent studies have demonstrated that organophosphorus insecticides (OPI) possess the potential to disrupt glucose homeostasis leading to hyperglycemia in experimental animals. The propensity of OPI to induce hyperglycemia along with oxidative stress may have far-reaching consequences on diabetic outcomes and associated complications. The primary objective of this study was to assess the potential of monocrotophos (MCP), an extensively used OPI, on hepatic and renal oxidative stress markers and dysregulation of hepatic glucose homeostasis in experimentally induced diabetic rats. Rats rendered diabetic by a single dose of streptozotocin (60 mg/kg b.w) were orally administered MCP (0.9 mg/kg b.w/d for 5 d). Monocrotophos per se caused only a marginal increase in blood glucose levels but significantly elevated the blood glucose levels and also disrupted glucose homeostasis by depleting liver glycogen content and increasing the gluconeogenetic enzyme activities in diabetic rats. Experimentally induced diabetes was also associated with alterations in antioxidant enzymes in liver and kidney. MCP markedly enhanced lipid peroxidation in kidney and altered the enzymatic antioxidant defense mechanisms in both liver and kidney of diabetic rats. Collectively our data provides evidence that MCP has the propensity to augment the oxidative stress and further disrupt glucose homeostasis in diabetic rats.