Acute stress hyperglycemia in cats is associated with struggling and increased concentrations of lactate and norepinephrine

We characterized the changes in blood glucose concentrations in healthy cats exposed to a short stressor and determined the associations between glucose concentrations, behavioral indicators of stress, and blood variables implicated in stress hyperglycemia (plasma glucose, lactate, insulin, glucagon, cortisol, epinephrine, and norepinephrine concentrations). Twenty healthy adult cats with normal glucose tolerance had a 5-minute spray bath. Struggling and vocalization were the most frequent behavioral responses. There was a strong relationship between struggling and concentrations of glucose and lactate. Glucose and lactate concentrations increased rapidly and significantly in all cats in response to bathing, with peak concentrations occurring at the end of the bath (glucose baseline 83 mg/dL, mean peak 162 mg/dL; lactate baseline 6.3 mg/dL, mean peak 64.0 mg/dL). Glucose response resolved within 90 minutes in 12 of the 20 cats. Changes in mean glucose concentrations were strongly correlated with changes in mean lactate (r = .84; P < .001) and mean norepinephrine concentrations (r = .81; P < .001). There was no significant correlation between changes in mean glucose concentrations and changes in mean insulin, glucagon, cortisol, or epinephrine concentrations. Struggling and lactate concentrations were predictive of hyperglycemia. Gluconeogenesis stimulated by lactate release is the likely mechanism for hyperglycemia in healthy cats in this model of acute stress. Careful handling techniques that minimize struggling associated with blood collection may reduce the incidence of stress hyperglycemia in cats.     

Short-term effects of energy changes on plasma leptin concentrations and glucose tolerance in healthy ponies

To determine whether plasma leptin concentrations and glucose tolerance are affected by changes in energy balance, nine healthy Shetland ponies were fed at 140% followed by 75% of their maintenance requirements for 13 days in each of the two periods. Bodyweight was recorded every three days. Blood samples were taken every two days and analysed for leptin and cortisol. An oral glucose tolerance test was performed on day 7 of each period. Serial blood samples were analysed for glucose and insulin. Although bodyweight was not affected, plasma leptin concentrations increased (P<0.001) initially during overfeeding, but returned to previous values after 7 days. During underfeeding, plasma leptin concentrations decreased (P<0.001). Underfeeding was associated with a higher AUC for plasma glucose (P=0.02) and plasma insulin (P=0.05) resulting in a decreased glucose tolerance (AUC glucose/AUC insulin; P=0.008), probably due to a plasma cortisol increase caused by the reduced feed intake. It is concluded that changes in energy balance, without altering bodyweight, can influence plasma leptin concentrations in ponies.     

Stability of plasma metabolites and hormones in parturient dairy cows

Metabolic changes that accompany the transition from parturition to lactation in dairy cows were studied. To measure these changes, plasma samples were obtained from 20 mature Holstein-Friesian dairy cows 10 days before through 10 days after parturition. They were analyzed for glucose, free fatty acids (FFA), lactic acid, ketone bodies, glucocorticoids, insulin, and growth hormone concentration. Lactic acid and glucocorticoids remained constant during the experiment, except for the day of parturition itself. In the prepartum period, changes were not detected in concentrations of hormones (glucocorticoids, insulin, and growth hormone), whereas, plasma metabolites began changing prior to parturition. Most evident were prepartum increased in FFA, ketones, and glucose. Postpartum plasma glucose concentration rapidly returned to prepartum concentrations. Plasma concentration of FFA and ketone bodies remained elevated for longer periods.     

Energy metabolism in the newborn farm animal with emphasis on the calf: endocrine changes and responses to milk-born and systemic hormones

Neonatal mammals need adaption to changes in nutrient supply because energy intake shifts from continuous parenteral supply of nutrients (mainly glucose, lactate, and amino acids) via the placenta to discontinuous colostrum and milk intake with lactose and fat as main energy sources. Besides ingested lactose, endogenous glucose production is essential in the neonate to assure sufficient glucose availability. Fetal endogenous glucose production is low, but endocrine changes (especially the prenatal rise of glucocorticoid production) promote maturation of metabolic pathways that enable marked glycogen synthesis before and enhanced gluconeogenesis after birth to establish an adequate glucose status during postnatal maturation. In preterm born farm animals gluconeogenic activity is low, mainly because of a low glucocorticoid and thyroid status. In full-term neonates, endogenous glucose production increases with age. Colostral bioactive components (such as growth factors, hormones, bioactive peptides, and cytokines) do not have a direct effect on endogenous glucose production. However, colostrum feeding stimulates intestinal growth and development, an effect at least in part mediated by bioactive substances. Increased nutrient and glucose absorption thus allows increased glucose supply and hepatic glycogen storage, which improves the glucose status. The improved energetic status of colostrum-fed neonates is reflected by an accelerated maturation of the somatotropic axis, leading especially to enhanced production of IGF-I in the neonate. Secretion and production of hormones involved in the regulation of glucose and fat metabolism in neonates depend on the developmental stage and the response to feeding. In addition, many such hormones have actions in the neonate that differ from adult animals. Endocrine action to support endogenous energy supply in neonates is probably not fully established, and therefore, needs postnatal maturation. Therefore, our knowledge on energy metabolism in the neonate needs to be extended to better understand the function and the failure and to assess endocrine responses during the neonatal period.     

Changes in blood glucose and insulin responses to intravenous glucose tolerance tests and blood biochemical values in adult female Japanese black bears (Ursus thibetanus japonicus)

The metabolic mechanisms to circannual changes in body mass of bears have yet to be elucidated. We hypothesized that the Japanese black bear (Ursus thibetanus japonicus) has a metabolic mechanism that efficiently converts carbohydrates into body fat by altering insulin sensitivity during the hyperphagic stage before hibernation. To test this hypothesis, we investigated the changes in blood biochemical values and glucose and insulin responses to intravenous glucose tolerance tests (IVGTT) during the active season (August, early and late November). Four, adult, female bears (5-17 years old) were anesthetized with 6 mg/kg TZ (tiletamine HCl and zolazepam HCl) in combination with 0.1 mg/kg acepromazine maleate. The bears were injected intravenously with glucose (0.5 g/kg of body mass), and blood samples were obtained before, at, and intermittently after glucose injection. The basal triglycerides concentration decreased significantly with increase in body mass from August to November. Basal levels of plasma glucose and serum insulin concentrations were not significantly different among groups. The results of IVGTT demonstrated the increased peripheral insulin sensitivity and glucose tolerance in early November. In contrast, peripheral insulin resistance was indicated by the exaggerated insulin response in late November. Our findings suggest that bears shift their glucose and lipid metabolism from the stage of normal activity to the hyperphagic stage in which they show lipogenic-predominant metabolism and accelerate glucose uptake by increasing the peripheral insulin sensitivity.     

Effect of feeding glucose, fructose, and inulin on blood glucose and insulin concentrations in normal ponies and those predisposed to laminitis

Identification of ponies (Equus caballus) at increased risk of pasture-associated laminitis would aid in the prevention of the disease. Insulin resistance has been associated with laminitis and could be used to identify susceptible individuals. Insulin resistance may be diagnosed by feeding supplementary water-soluble carbohydrate (WSC) and measuring blood glucose and insulin concentrations. The aim of this study was to assess the glycemic and insulinemic responses of 7 normal (NP) and 5 previously laminitic (PLP), mixed breed, native UK ponies fed glucose, fructose, and inulin [1 g/(kg(.)d) for 3 d] or no supplementary WSC (control) in spring and fall after a 7-d adaptation to a pasture or hay diet. Blood samples were taken for 12 h after feeding on each day, and baseline and peak concentrations and area under the curve (AUC) for glucose and insulin were recorded. Linear mixed models were used for statistical analysis. Differences between PLP and NP groups were most marked after glucose feeding with differences in peak glucose (P = 0.02) and peak insulin (P = 0.016) concentrations. Season and diet adaptation also affected results. Peak concentrations of glucose and insulin occurred 2 to 4 h after WSC feeding. Peak insulin concentration was greater and more variable in fall, particularly in PLP adapted to fall pasture. Baseline glucose and insulin concentrations varied between individuals and with season and diet adaptation but were not greater in PLP than NP. Insulin AUC was greater in PLP than NP after feeding both glucose and fructose (P = 0.017), but there were no differences between PLP and NP in glucose AUC. Glycemic and insulinemic changes were less (P ≤ 0.05) after feeding fructose than glucose, although differences between PLP and NP were still evident. Minimal changes in glucose and insulin concentrations occurred after inulin feeding. Measurement of peak insulin 2 h after feeding of a single dose of glucose (1 g/kg) may be a simple and practical way to aid identification of laminitis-prone ponies before the onset of clinical disease, particularly when ponies are adapted to eating fall pasture.     

Glycaemic and insulinaemic responses to mechanical or thermal processed barley in horses

This study was conducted to evaluate the effects of different barley processing techniques on the glycaemic and insulinaemic responses in horses. It was hypothesized that the changes in pre-caecal starch digestibility caused by barley processing would affect metabolic responses. Six horses were fed in random order: whole (WB), finely ground (FGB), steamed (SB), steam-flaked (SFB) and popped barley (PB). The total barley intake was adjusted to 630 g starch/horse/day (1.2-1.5 g starch/kg BW/day). During a 10-day stabilization period, the horses also received 6 kg grass hay/horse/day. On the blood collection day, the horses were fed their test diet (exclusively barley), and blood samples were taken at defined times for glucose and insulin analysis. The degree of starch gelatinization (DG) in the untreated or thermally processed barley was analysed using the glucoamylase method. In general, barley feeding resulted in a significant increase in mean plasma glucose and insulin concentrations within 30-45 min after feeding. While the highest glucose and insulin responses occurred after intake of SFB with a DG of 28.7%, the changes in glucose and insulin were more pronounced with PB with a DG of 95.6%, with SB (DG: 22.2%), FGB (DG: 14.9%) and WB (DG: 14.9%). The peak plasma glucose varied between 5.72 +/- 0.67 mmol/l with FGB and 6.52 +/- 0.64 mmol/l with SFB (treatment p < 0.05). These results confirm the post-prandial changes in plasma glucose and insulin after intake of the different barley products, but also show that there was no association of the highest degree of gelatinization in the different barley diets with the most pronounced glycaemic or insulinaemic response.     

Comparison of two formulations of buprenorphine in cats administered by the oral transmucosal route

This randomised, blinded, cross-over study investigated the ease of oral transmucosal administration of two formulations of buprenorphine using glucose as a control in 12 cats. The cats received three treatments: buprenorphine multi-dose, buprenorphine and the equivalent volume of glucose 5%. Ease of treatment administration, observation of swallowing, changes in pupil size, sedation, salivation, vomiting, behaviour and food intake were assessed. The data were analysed using MLwiN and multi-level modelling. Ease of administration of buprenorphine multi-dose was statistically different from glucose (P <0.001), and the administration of all treatments became easier over the study periods. Swallowing was not statistically different between groups (P >0.05). Mydriasis was evident after the administration of both formulations of buprenorphine. Sedation, salivation, vomiting, behavioural changes or in-appetence were not observed after any treatment. Cats tolerated oral transmucosal administration of glucose better than buprenorphine multi-dose, while buprenorphine administration was tolerated as well as glucose.     

鸡体细胞诱导重编程早期的糖代谢变化研究

为研究鸡体细胞诱导重编程早期的糖代谢方式的变化,试验采用OCT4、SOX2、NANOG和LIN28A(OSNL)四因子诱导体系将鸡胚成纤维细胞(Chicken embryo fibroblasts,CEF)重编程为诱导多能干细胞(Induced pluripotent stem cells,iPS),并利用碱性磷酸酶染色、阶段特异性胚胎抗原1(Stage-specific embyronic antigen-1,SSEA-1)免疫荧光染色、体外诱导分化及多能性基因表达检测等对iPS进行鉴定。通过检测重编程过程中糖代谢相关基因表达及酶活性的变化,并对葡萄糖摄取量、乳酸产生量及线粒体膜电位检测等研究鸡体细胞诱导重编程早期的糖代谢变化。结果显示,鸡CEF诱导重编程形成的iPS呈碱性磷酸酶染色阳性,表达SSEA-1蛋白,体外分化形成类胚体且表达多能性标记基因。同时重编程过程中氧化磷酸化基因表达下调而糖酵解相关基因表达上调,糖酵解关键酶活性均增强,且iPS的葡萄糖吸收量及乳酸产生量增加,而线粒体膜电位则下降。结果表明,OSNL四因子体系将鸡CEF诱导重编程形成iPS的过程中,细胞的主要糖代谢方式从氧化磷酸化转变为糖酵解,而糖酵解的激活可能会进一步促进iPS的形成。     

Comparison of Insulin and Glucose Metabolism in Horses with Pituitary Pars Intermedia Dysfunction Treated Versus Not Treated with Pergolide

Equine pituitary pars intermedia dysfunction (PPID) is known to alter glucose/insulin metabolism. This study evaluated changes in parameters relating to glucose/insulin metabolism and determined whether there is a difference between pergolide-treated and untreated animals. We hypothesized that glucose/insulin dynamics in PPID horses receiving pergolide would be different than those in untreated horses. A total of 38 horses with diagnoses of PPID were included in the study (average age: 24 years). A total of 25 horses were untreated; 13 horses were treated with pergolide (>3 months). Parameters relating to glucose/insulin metabolism were determined in all horses, as follows: adrenocorticotropin-releasing hormone (ACTH), insulin, fructosamine, triglyceride, glucose, modified insulin-to-glucose ratio (MIRG), and reciprocal of the square root of insulin (RISQI). A combined glucose-insulin test (CGIT) was performed in 23 horses as not all owners agreed to the testing. Treated animals showed a tendency to have lower ACTH, but results were not significant. All animals had fructosamine levels exceeding reference values (mean value 314 ± 32 μmol/L; reference range: <280 μmol/L). There were no statistically significant differences between insulin, glucose, ACTH, triglycerides concentrations, RISQI/MIRG calculations, and CGIT results of pergolide-treated PPID and those of untreated horses. Five horses (13.2%) had combined hyperglycemia/hyperinsulinemia, whereas 7 horses (18.4%) displayed hyperglycemia, and 3 horses (7.9%) showed hyperinsulinemia alone. Forty percent of the horses with altered glucose/insulin metabolism were treated with pergolide. Based on RISQI and MIRG calculations, 19 animals displayed changes in glucose/insulin metabolism. Fourteen of twenty-three horses (61%) showed signs of insulin resistance in CGIT results. In conclusion, PPID horses frequently show alterations in glucose/insulin metabolism, but no significant differences were found between treated and untreated animals. Changes in insulin/glucose dynamics may not be a useful indicator of response to pergolide treatment.     

Influence of seasonal forage quality on glucose kinetics of young beef cows

Extensive range livestock production systems in the western United States rely heavily on rangeland forages to meet the nutritional needs of grazing livestock throughout the year. Interannual variation in the quantity and quality of rangeland forage in the Northern Great Plains, as well as throughout much of the western United States, may play a pivotal role in how well grazing ruminants sequester nutrients in their tissues. This variation in forage quality may influence the ability of a beef cow to utilize dietary nutrients via changes in tissue responsiveness to insulin. Identifying specific periods and production states in which this phenomenon is manifested will provide insight into the development and implementation of strategic and targeted supplementation practices that improve nutrient utilization during times of nutritional imbalance and may improve the lifetime productivity of grazing range beef cows. A 2-yr study was conducted to monitor serum metabolites, glucose kinetics during glucose tolerance tests, and forage chemical composition every 90 d in young cows (2 to 4 yr of age; n = 28). In yr 1 and 2, cows were managed on 4 pastures varying in size from 36 to 76 ha in yr 1 and 49 to 78 ha in yr 2. Regardless of year, cow age, or cow physiological status, the main factor influencing glucose half-life was season of the year (P = 0.02). Effects of season on glucose half-life closely followed assessments describing forage quality, with glucose half-lives of 46, 39, 43, and 51 +/- 3.9 min for May, August, December, and March, respectively. Elevated glucose half-life during seasons in which forage quality is of lower nutritive value indicated that tissue responsiveness to the actions of insulin followed seasonal changes in forage quality. Glucose half-life tended (P = 0.09) to decrease between May and August, increased (P = 0.04) between December and March, and showed a tendency (P = 0.10) to decrease in seasons of greater nutrient density (May and August) compared with seasons of lower nutrient density (December and March). Seasonal changes in serum metabolites were also observed and corresponded with changes in forage quality. The results support our hypothesis that as the season progresses and forage quality declines, maternal tissues become less responsive to insulin, indicating that targeted supplementation with glucogenic precursors during these seasons of nutritional stress may improve cow performance.     

Effects of clonidine on glucose production and insulin secretion of cattle

Clonidine-2-(2,6-dichlorophenylamine)-2-imidazoline hydrochloride, a potent alpha-adrenoceptor stimulant, was given to dairy heifers. Administration of either 2 or 20 microgram of drug/kg during 10 minutes resulted in decreased immunoreactive serum insulin (IRI) concentrations and increased serum glucose concentrations 5 minutes after administration. Drug administration resulted in a protracted decrease (P less than 0.01) of serum IRI and a protracted increase (P less than 0.01) in serum glucose. Doses differed significantly (P less than 0.01) with regard to their ability to alter IRI and glucose concentrations. Clonidine also significantly (P less than 0.05) enhanced glucose release from liver slices of heifers in vitro. Clonidine stimulated cyclic 3'5' adenosine monophosphate (cAMP) production in liver tissue slices when they were incubated in the presence (or absence) of theophylline, indicating that the mechanisms bringing about changes in liver glucose release and cAMP production were related.     

Effects of long-term administration of recombinant bovine somatotropin on the concentration of metabolites in milk in different stages of lactation in crossbred Holstein cattle

Effects of long‐term treatment with recombinant bovine somatotropin (rbST) on concentrations of cellular metabolites in the milk of 87.5% crossbred Holstein cattle were performed. The peak milk yield of rbST‐treated animals was 22% higher (P < 0.05) than that of the control animals in early lactation. The mammary glucose uptake of rbST‐treated animals increased in early lactation, but decreased in mid and late lactation, while plasma glucose concentrations were not affected. Lactose and milk triacylglycerol secretion of rbST‐treated animals significantly increased (P < 0.05) when compared with those of control animals in early lactation. The concentrations of milk glucose of rbST‐treated animals significantly increased in early and mid‐lactation (P < 0.05). The concentrations of milk galactose markedly increased (P < 0.05) whereas the concentrations of milk uridine 5′‐diphosphoglucose (UDP‐glucose) and UDP‐galactose showed no significant changes as lactation advances in both groups. The concentrations of isocitrate, 2‐oxoglutarate and citrate in milk from both groups showed no significant changes throughout experiment. The concentration of glucose‐6‐phosphate (G6P), glucose‐1‐phosphate and cyclic adenosine 3,5′monophosphate in milk from both groups markedly decreased as lactation advances exception in early lactation of rbST‐treated animals, which G6P was not affected. These findings suggest that prolonged rbST treatment exerts its galactopoietic action at least in early lactation through both intramammary and extra‐mammary changes. Increases in the concentrations of glucose and G6P in milk maintained the level of pretreatment in early lactation associated with increases in milk yields during rbST administration, reflect their concentrations in the cytosol or Golgi vesicles of mammary cells, which would be one of the factors regulating intermediary metabolites in the lactose biosynthetic pathway.     

Metabolism of naturally occurring [13C]glucose given orally to horses

In 5 horses, 13CO2/12CO2 ratios in expired air were determined using isotope mass spectroscopy to investigate metabolism of naturally occurring [13C]glucose. Oral glucose tolerance tests (OGTT) were performed using maize or beet glucose. Maize has a higher 13C concentration than that of most plants. The 13CO2/12CO2 ratios after OGTT was performed using maize glucose were compared with 13CO2/12CO2 ratios in expired air after OGTT was performed using beet glucose. The ratio also was determined during the period horses were not fed. Using OGTT, all horses were glucose tolerant. The OGTT performed using beet glucose led to minimal changes in 13CO2/12CO2 ratios. The 13CO2/12CO2 ratios decreased significantly (P less than 0.01) when horses were not fed. After oral dosing with maize glucose, 13CO2/12CO2 ratios reached maximal increases 5 hours after dosing and reached baseline values 15 hours after dosing.     

Dietary impact on circulating glucose profiles in the white rhinoceros

Excess dietary glucose may be a factor in several captive wildlife diseases and reproductive abnormalities. The first step in understanding the health consequences of diets high in glucose is to characterize how dietary glucose concentrations change circulating glucose profiles. We adapted the glycemic index approach to detect differences in blood glucose concentrations in white rhinos in response to different meals. Six white rhinos were fasted overnight then randomly assigned to be fed 5 kg of grass hay and one of five meals varying in digestible energy (DE) availability and source (10% DE glucose, 5% DE glucose, 10% DE pelleted horse feed, 10% DE lucerne hay, 10% DE grass hay). After eating, the blood glucose response peaked 45–90 min later and remained elevated up to 180 min. Area under the curve results demonstrated that the blood glucose response was not different between diets. However, at 90 min, serum glucose levels in rhinos eating the 10% lucerne hay diet were significantly lower than the 5% glucose and 10% glucose diets but not the 10% pellet nor 10% grass hay diets. The changes in blood glucose responses to different diets were similar in magnitude to reported domestic horse profiles but are higher than predicted by allometric scaling. We conclude that the grass hay, lucerne hay and low glycemic index horse pellets fed in this study resulted in similar blood glucose responses in white rhinos. The validation of the methodology used in this study is a first step towards elucidating the relationship between glucose, obesity, health and reproduction in rhinos.     

A genetic analysis of the concentrations of blood metabolites and their relationships with age and liveweight gain in young British Friesian bulls

Blood samples were taken from 428 young British Friesian bulls, the sons of 72 sires, between 3 and 15 months of age. The concentrations of blood glucose and haemoglobin and serum cholesterol, urea, albumin, globulin, inorganic phosphate, Ca, Mg, Na, K and Cu were measured and correlated with age and growth rate.Most of the constituents showed highly significant but small changes in concentration with age. The largest changes occurred in the concentrations of urea, albumin and haemoglobin which increased as bulls reached maturity. The concentrations of urea, albumin and globulin were also lower and concentrations of glucose, inorganic phosphate, Ca and K higher than usually occur in older cattle.Highest estimates of heritability, based on the mean of 3 samples, were for K and globulin (> 0.6) and for haemoglobin, cholesterol, inorganic phosphate, Cu and glucose (0.4–0.6). Phenotypic correlations between 0.2 and 0.4 occurred with growth rate for albumin and glucose between 24 and 35 weeks and with body weight for albumin between 27 and 50 weeks of age; however, the phenotypic correlations with average growth rate up to 53 weeks were only 0.15 and 0.07 for albumin and glucose, respectively. Genetic correlations with growth rate were also determined, but standard errors were large.     

Effect of regular walking exercise on glucose tolerance and insulin response to i.v. glucose infusion in growing beef steers

The purpose of the present paper was to investigate the effect of regular walking exercise on glucose tolerance and insulin response to i.v. glucose infusion in growing beef steers. Four crossbred beef steers walked on a treadmill during a 6 week exercise period (1.2 km/h, 1 h/day and 5 days/week). The changes in plasma glucose and insulin levels following glucose infusion were analyzed immediately prior to (bodyweight: 260.4 ± 24.2 kg) and after (295.7 ± 30.1 kg) the exercise period. The basal levels of plasma glucose (86.4 vs. 82.0 mg/dL, P = 0.040) and insulin (24.5 vs. 14.3 μU/mL, P = 0.016) were significantly lower after the exercise period. Further, the increase in the levels of plasma glucose (420.4 vs. 280.8 mg/dL, P < 0.001) and insulin (94.5 vs. 73.1 μU/mL, P = 0.028) following the glucose infusion decreased after the exercise period. The area under the curve of plasma glucose (108.8 vs. 62.9 mg/dL per min, P < 0.001) and insulin (53.6 vs. 29.7 μU/mL per min, P = 0.018) indicated more rapid clearance of exogenous glucose and less insulin secretion for glucose clearance after the exercise period. These results suggest that regular exercise improves glucose tolerance, with lower insulin response to glucose infusion in growing steers, as observed in rodents and humans.     

Diagnostic utility of glycosylated hemoglobin concentrations in the cat

Changes in glycosylated hemoglobin (GHb) concentrations, K values (% disappearance of glucose/min after an intravenous injection of 1 g/kg dextrose), and blood glucose concentrations were examined in eight cats before and during the induction of diabetes, and in four of these cats after they were placed on insulin treatment. There was a statistically significant separation of GHb, K values, and fasting blood glucose concentrations between healthy and diabetic cats. Changes in GHb correlated best with the K value and single weekly fasting glucose concentrations averaged over eight periods for each cat while diabetes was induced (R = 0.80 and 0.78, respectively); however, fasting blood glucose concentrations obtained on the day of the GHb measurement were also highly correlated (R = 0.69; P < 0.001). The correlation between GHb and single weekly glucose concentrations obtained in insulin-treated cats at the time of insulin peak action and averaged over an 8-wk time period for each cat was less but still significant (R = 0.53; P < 0.001). It is concluded that GHb measurements are a simple and reliable way to monitor changes in glucose control in the diabetic cat over a prolonged period.     

Adenosine deaminase and porcine meat quality. II. Effects of adenosine analogues on plasma free fatty acids, glucose and lactate in pigs representing high and low adenosine deaminase red cell activity

The adenosine analogues 5'-(N-ethyl) carboxamidoadenosine (NECA) and N6-(phenylisopropyl) adenosine (R-PIA) were shown to differ in their effect on the plasma level of free fatty acids (FFA), glucose and lactate in pigs representing low (Ada 0) and high (Ada A) red cell adenosine deaminase activity. At the same dosage range (0.001-0.005 mg/kg) R-PIA produced a much stronger suppression of the FFA level than NECA, indicating that A1 adenosine receptors predominate in porcine adipose tissue. Pretreatment with 8-phenyltheophylline completely abolished the antilipolytic effect of both adenosine analogues. NECA in contrast to R-PIA elevated the blood glucose concentration, suggesting that A2 adenosine receptors are involved in the stimulation of glycogenolysis. This effect of NECA was not altered by a beta-adrenoceptor blockade providing evidence for a direct effect of adenosine on glycogenolysis. Whereas the changes in plasma FFA following NECA administration were of similar magnitude in Ada A and Ada 0 pigs, the changes in the blood glucose concentration were different in these two groups of pigs.     

脂多糖致奶牛糖脂代谢异常研究进展

脂多糖（LPS）是革兰阴性菌细胞壁的主要成分,广泛存在于环境中,可诱导机体炎症反应,与奶牛的多种疾病相关。环境和疾病等因素引起机体LPS水平升高,LPS与巨噬细胞、中性粒细胞和上皮细胞等作用,激活NF-κB和MAPKs信号通路,释放炎症因子,改变机体糖脂代谢相关激素和脂肪因子水平,进而影响糖脂代谢,造成奶牛2型糖尿病、酮病、脂肪肝和肥胖等代谢性疾病。本文综述了LPS与炎症反应和糖脂代谢相互作用关系及其导致糖脂代谢异常作用机制,为LPS致奶牛糖脂代谢异常机理研究提供参考。