[Show abstract][Hide abstract] ABSTRACT: Glucagon-like peptide 1 (GLP-1) is a glucose-lowering, intestinal-derived factor with multiple physiological effects, making it attractive for diabetes therapy. However, the therapeutic potential of endogenous GLP-1 is limited, because of rapid inactivation by dipeptidyl peptidase-4. Recently, enhanced incretin preparations, such as liraglutide, have emerged, which are more resistant to degradation and longer lasting. Liraglutide is a long-acting acylated human GLP-1 receptor agonist, with a 97% amino acid sequence identity to endogenous human GLP-1, and 100% amino acid sequence homology with canine GLP-1.
Full-text · Article · Apr 2013 · Research in Veterinary Science
[Show abstract][Hide abstract] ABSTRACT: Insulin detemir is the first member of a new class of long-acting soluble insulin analogues capable of maintaining the basal level of insulin in humans. In this preliminary study, we investigated the time-action profiles of insulin detemir in normal and diabetic dogs since the use of insulin detemir in canines has yet to be determined. Eight animals were used in our study (three normal and five insulin dependent diabetic dogs). Time-action profiles of insulin detemir were monitored in normal dogs using an artificial pancreas apparatus under euglycemic condition. Blood sampling was performed at 2h intervals post feeding, with insulin administration, in insulin dependent diabetic dogs. Time-action profiles of insulin detemir, in normal dogs, demonstrated that insulin detemir is a long-lasting preparation similar to what has been observed in humans. A pronounced peak was detected at 8-10h while the glucose-lowering effect lasted for over 24h after insulin injection, thus illustrating its longer prolonged peak activity time. Furthermore, intensive glycemic control was achieved with insulin detemir in insulin dependent diabetic dogs, using a lower dosage than NPH insulin and insulin glargine therapeutic doses. Our results indicate that insulin detemir has a greater effect than either NPH insulin or insulin glargine in canines, requiring a lower dose than either insulin preparation. However, using insulin detemir also carries a higher risk of inducing hypoglycemia as compared to either NPH insulin or insulin glargine.
Full-text · Article · Jun 2011 · Research in Veterinary Science
[Show abstract][Hide abstract] ABSTRACT: Metabolite, insulin and adiponectin concentrations and LDH, AST and ALT activities were measured in plasma of 142 client-owned cats (1-13years old, 16 breeds) to set up a new criterion of hypertriglyceridemia (hyper-TG) with increased plasma insulin concentrations for early diagnosis of lipid metabolism abnormality including obesity. 25 cats with over 165mg/dl of plasma triglyceride (TG) concentrations were decided as hyper-TG with increased plasma insulin concentrations, and prevalence of hyper-TG was 16.7% in young (1-6years old) and 18.3% in old (>7years old) cats examined. In the hyper-TG cats, their plasma TG concentrations increased to 6.6-7.4-fold of the values of control cats with 35-50mg/dl of plasma TG and their plasma cholesterol, FFA and insulin concentrations and LDH and ALT activities increased significantly, whereas their plasma adiponectin concentrations decreased significantly compared to those in the control cats. Hyper-TG cats with significantly increased body weights and plasma insulin and decreased plasma adiponectin seemed to be in early stage of obesity accompanying increased plasma insulin concentrations. Increased TG, insulin, LDH and ALT and decreased adiponectin values in plasma seemed to be key factors for diagnosis of lipid metabolism abnormality at early stage in cats.
No preview · Article · Jun 2010 · Research in Veterinary Science
[Show abstract][Hide abstract] ABSTRACT: Glimepiride and nateglinide are two common oral hypoglycemic agents currently being used with humans suffering from Type 2 diabetes mellitus. Neither drug has been tested with cats thus far and it is currently unknown whether either of these drugs exert any effect in cats or not. The objective of this study was to determine the effect of glimepiride and nateglinide on glucose and insulin responses in healthy control cats, in order to determine their potential use in diabetic cats. The intravenous glucose tolerance tests was carried out since it is an excellent test for evaluating pancreatic beta-cell function for insulin secretion. Alterations in the insulin secretion pattern can be perceived as the earliest sign of beta-cell dysfunction in many species, including cats. Nateglinide demonstrated a quick action/short duration type effect with serum glucose nadiring and insulin response peaking at 60 and 20 minutes, respectively. Alternatively, glimepiride is medium-to-long acting with serum glucose nadiring and insulin response peaking at 180 minutes and 60 minutes, respectively. Nateglinide's potency was evident allowing it to induce a 1.5-2 higher preliminary insulin peak (3.7 +/- 1.1 pg/ml) than glimepiride's (2.5 +/- 0.1 pg/ml), albeit only for a short period of time. Because glimepiride and nateglinide have a shared mode of action, no significant differences in overall glucose AUC(0-360 min) (24,435 +/- 2,940 versus 24,782 +/- 2,354 mg min/dl) and insulin AUC(0-360 min) (410 +/- 192 versus 460 +/- 159) in healthy control cats were observed. These findings may provide useful information when choosing a hypoglycemic drug suited for the treatment of diabetic cats depending on the degree of diabetes mellitus the cat is suffering from.
Full-text · Article · Oct 2009 · Veterinary Research Communications
[Show abstract][Hide abstract] ABSTRACT: Circulating levels of monosaccharides can act as a reflection of systemic glucose/ energy metabolism. Characteristic changes observed in these levels can be seen in patients with diabetes and other metabolic disorders. There have been a few reports describing the significance of mannose metabolism as an energy source under physiological and pathological conditions. However, the relationship between circulating levels of mannose and the pathophysiology of diabetes mellitus are unknown in dogs. This study examined circulating levels of mannose between healthy control and diabetic dogs and evaluated the clinical significance of mannose levels in dogs. Diabetic dogs demonstrated a higher circulating level of mannose in comparison to normal healthy control dogs. Plasma mannose was positively correlated with plasma glucose and fructosamine, respectively. Interestingly, plasma mannose levels were affected by plasma insulin levels. In the context of feeding and glucose tolerance tests, plasma mannose levels responded to changes in circulating insulin levels. Circulating plasma mannose levels decreased after feeding in both control and diabetic animals in spite of observed insulin level differences. However, when glucose tolerance tests were given, a positive correlation between mannose levels and insulin levels was observed. Therefore, plasma mannose levels obtained via glucose tolerance testing may be used as a new diagnostic method for evaluating insulin resistance or deficiency in diabetic dogs.
Full-text · Article · Jun 2009 · Veterinary Research Communications
[Show abstract][Hide abstract] ABSTRACT: Measurements of serum fructosamine, glycated hemoglobin, and glycated albumin (GA) complement serum glucose concentration for better management of diabetes mellitus (DM). Especially, the serum fructosamine test has long been used for diagnosing and monitoring the effect of treatment of DM in dogs. However, fructosamine tests are currently not performed in veterinary medicine in Japan. GA and fructoasmine levels have been shown to strongly correlate. However, the clinical implications of using GA remain to be elucidated. Therefore, the purpose of the current study was threefold: 1) Determine whether GA% is altered by acute hyperglycemia in normal dogs, simulating stress induced hyperglycemia; 2) Demonstrate that GA% does not dynamically change with diurnal variation of blood glucose concentration in diabetic dogs; and 3) Investigate whether GA% is capable of providing an index of glycemic control for 1-3 weeks in diabetic dogs as is the case with diabetic human patients. Our study demonstrated that serum GA% remains very stable and unaltered under acute hyperglycemic conditions (intravenous glucose injection) and in spite of diurnal variation of blood glucose concentration. Furthermore, serum GA% can reflect long-term changes (almost 1-3 weeks) in blood glucose concentration and the effect of injected insulin in diabetic dogs.
Full-text · Article · Jun 2009 · Veterinary Research Communications
[Show abstract][Hide abstract] ABSTRACT: In order to evaluate the immune state of dogs suffering from pituitary-dependent hyperadrenocorticism (PDH), peripheral lymphocyte subsets were examined. Twenty seven PDH dogs and eight healthy control dogs were used in the current study. Eight healthy dogs served as the control group. Twenty seven PDH dogs were categorized into 4 groups based on their post serum cortisol concentrations by ACTH stimulation test: 2-5, excellent control (n = 8); 5-20, fair control (n = 7); >20, poor control (n = 4); and untreated (n = 8). Cell counts were executed with white blood cells (WBC), lymphocytes, CD3(+) (T lymphocytes), CD4(+) (Helper T lymphocytes), CD8(+) (Cytotoxic T lymphocytes), CD21(+) (B lymphocytes) cells in addition to calculating CD4(+)/CD8(+) ratio. Results indicated a significant difference in lymphocyte numbers and lymphocyte subset populations (CD3(+), CD4(+), CD8(+), and CD21(+) cells) between PDH and control dogs. Moreover, comparison of the PDH groups (excellent control; fair control; poor control; untreated) demonstrated that all groups had a significant decrease in lymphocytes numbers (CD3(+), CD4(+) and CD21(+) cell counts) as compared to control group. Meanwhile, no significant differences were observed in WBC counts and CD4(+)/CD8(+) ratio between groups. Furthermore, lymphocyte subset distribution in excellent control PDH dogs without concurrent disease (n = 4) better resembled that of control dogs as compared to PDH dogs with concurrent disease (n = 4). PDH dogs may be suffering from an immuno-depressed state as evidenced by significant differences in lymphocyte subset populations. Furthermore, treatment of both PDH and concurrent disease might improve lymphocyte subset distribution.
Full-text · Article · May 2009 · Veterinary Research Communications
[Show abstract][Hide abstract] ABSTRACT: Dietary therapy is an important treatment component for diabetes mellitus (DM). In this study, the impact of three different commercially available diet regiments (1 general use and 2 aimed for treating obesity and DM) on short-term post-prandial serum glucose and insulin concentrations of five healthy cats to better understand what impact each of these diets may have for diabetic cats. The diet regiments used in this study were as follows: C/D dry (General Use- Low protein, High fat, High carbohydrate, and Low fiber), M/D dry (DM- High protein, High fat, Low carbohydrate, and High Fiber), and W/D dry (DM- Low Protein, Low Fat, High Carbohydrate, and High Fiber). No significant difference in post-prandial serum glucose levels were observed with the C/D (84.6 +/- 1.5 mg/dl) and W/D (83.8 +/- 1.4 mg/dl) dry diets when compared to pre-prandial fasting levels (83.9 +/- 1.4 mg/dl). However, a significant reduction was observed with the M/D diet (78.9 +/- 0.8 mg/dl) which had 50-60% less carbohydrates than either C/D or W/D diet. Unlike what was observed with post-prandial glucose levels, an interesting pattern emerged with post-prandial insulin levels, which were increasing with W/D, C/D, and M/D diets in that order (1.1 +/- 0.2, 1.7 +/- 0.2, and 2.3 +/- 0.2 ng/ml respectively). Most surprising, though, was the fact that the W/D diet did not seem to stimulate insulin secretion as compared to pre-prandial levels (1.1 +/- 0.1 ng/ml) in healthy cats. Interestingly, the W/D diet had high levels of carbohydrate and low levels of protein. Coincidentally, the only diet (M/D) which had a significant reduction in post-prandial glucose also showed the highest increase in post-prandial insulin in healthy cats. Therefore, dietary amounts of carbohydrate, fat, protein and fiber can all have an individual impact on post-prandial glycemia and subsequent insulin requirement levels. Just as concepts regarding dietary management of people with DM are evolving, investigators are reassessing what constitutes the ideal diet for the diabetic feline. As such, having a better understanding for each dietary component, may lead us to better understand how we can synergize certain dietary components to aid in DM management.
Full-text · Article · Apr 2009 · Veterinary Research Communications
[Show abstract][Hide abstract] ABSTRACT: Diabetes mellitus (DM) is a common endocrine disease in cats and dogs with increasing prevalence. Type 1 DM appears to be the most common form of diabetes in dogs whereas Type 2 DM prevails for cats. Since insulin resistance is more frequently encountered in cats than dogs, our laboratory was interested in determining whether differences at the insulin signaling pathway level and differences in glucose and lipid metabolism could be observed between cats and dogs. Insulin resistance has been positively correlated to insulin signaling pathway abnormalities. As such, this study measured insulin receptor substrate-1 (IRS-1), insulin receptor substrate-2 (IRS-2), and phosphatidylinositol 3-kinase (PI3-K) P-85alpha mRNA expression levels in classical insulin-responsive sensitive tissues (liver, skeletal muscle, and abdominal fat) and peripheral leukocytes between cats and dogs by qRT-PCR. Different tissues were sampled because it is currently unknown where insulin-resistance arises from. In addition, enzymes involved in glucose and lipid metabolism, malate dehydrogenase (MDH), glucose-6-phosphate dehydrogenase (G6PDH) and fatty acid synthase (FAS) were also assessed since glucose and lipid metabolism differs between cats and dogs. Overall, IRS-1, IRS-2, PI3-K, MDH, G6DPH, and FAS mRNA tissue expression profiles demonstrated different levels of expression, in various tissues for both canines and felines, which was expected. No distinct expression pattern emerged; however, differences were noted between canines and felines. In addition, IRS-1, IRS-2, PI3-K, MDH, G6DPH, and FAS mRNA expression was significantly higher in canine versus feline tissues, including peripheral leukocytes. Remarkable differences in insulin signaling gene expression between felines and canines indicate that cats may have an underlying low insulin sensitivity level due to low IRS-1, IRS-2, and PI3-K P-85alpha mRNA expression levels which would predispose cats to develop insulin resistance. Moreover, differences in glucose and lipid metabolism related gene expression (MDH, G6DPH, and FAS) demonstrate that felines have an overall lower metabolic rate in various tissues which may be attributed to overall lower insulin signaling gene expression and a lack of physical activity as compared to canines. Therefore, a combination of genetic and environmental factors appears to make felines more prone to suffer from insulin resistance and type 2 DM than canines.
Full-text · Article · Dec 2008 · Veterinary Research Communications
[Show abstract][Hide abstract] ABSTRACT: Intermediate insulin injections are commonly used for glycemic control in insulin dependent diabetic dogs acting as a replacement for natural insulin. Neutral Protamin Hagedorn (NPH) insulin and insulin glargine are two types of injectable insulin preparations commonly used in humans. In our study, we investigated the time-action profiles of both aforementioned insulin preparations in normal dogs in order to determine whether co-administration of NPH and glargine would be of benefit to insulin dependent diabetic dogs as it is for humans suffering from insulin dependent diabetes. Time-action profiles of NPH insulin and insulin glargine in normal dogs demonstrated a clear difference between both insulin preparations confirming that NPH insulin is an intermediate-acting preparation whereas insulin glargine is a long-lasting preparation. In addition, co-administration of NPH insulin and insulin glargine resulted in tight glycemic control as compared to NPH insulin alone in insulin dependent diabetic dogs. However, co-administration result in hypoglycemia at the dosages tested.
Full-text · Article · Jul 2008 · Veterinary Research Communications
[Show abstract][Hide abstract] ABSTRACT: Serum mannose and glucose concentrations in dogs before and after eating a meal were determined simultaneously with a recently established HPLC method combined with a UV and fluorescence detection system of p-aminobenzoic acid ethyl ester (ABEE)-derivatized monosaccharides. In this newly established HPLC method, detection limits were 0.09 micromol/L for mannose and 0.04 mmol/L for glucose. Linearity of peak areas vs. amounts of mannose and glucose in the range of 0.27-320 micromol/L and 0.13-64 mmol/L were observed, respectively. The value of the glucose content measured by the HPLC method was in good agreement with that of the commonly used enzymatic method (control). Serum glucose concentrations in dogs 90 min after the meal were almost the same as those before the meal, whereas serum mannose concentrations decreased significantly after the meal. This HPLC method may be useful for determination of monosaccharides in animal blood.
No preview · Article · Mar 2008 · Research in Veterinary Science
[Show abstract][Hide abstract] ABSTRACT: To investigate the effect of Agaricus mushroom meal on the energy metabolism in animal tissues; plasma glucose, triglyceride, cholesterol and immunoreactive insulin (IRI) concentrations and activities of enzymes related to energy metabolism in plasma and peripheral leukocytes were measured in Japanese Black WagyuxHolstein F1 calves supplemented with Agaricus blazei Murill (A. blazei) extract in milk-replacer at the dose of 60g/head/day for 4 weeks. Activities of malate dehydrogenase and aspartate aminotransferase in cytosol and glutamate dehydrogenase in mitochondria, and the malate dehydrogenase/lactate dehydrogenase ratio in cytosol in peripheral leukocytes of calves with A. blazei were significantly higher than those in control calves without A. blazei. It was concluded that supplementation of Agaricus mushroom meal extract was effective in activation of enzymes related to energy metabolism in peripheral leukocytes of calves.
No preview · Article · Mar 2007 · Research in Veterinary Science
[Show abstract][Hide abstract] ABSTRACT: Activities of enzymes related to energy metabolism and isoenzyme patterns of lactate dehydrogenase (LDH) were determined in peripheral leukocytes and livers of Holstein dairy cows and Institute of Cancer Research (ICR) mice. In dairy cow liver, activities of enzymes in glycolysis, malate-aspartate shuttle and lipogenesis were lower, but activities of glucose-6-phosphatase in gluconeogenesis were higher than those in mouse liver. Glucokinase activities were below detection limit in leukocytes and liver of the cows. Dairy cow leukocytes and liver showed the isoenzyme patterns with dominance of LDH-1, -2 and-3, whereas mouse leukocytes and liver showed that LDH-5 was dominant. The LDH isoenzyme patterns were very similar between leukocytes and liver in each animal species. Some enzymes in leukocytes may reflect those enzymes activities in liver and be a useful indicator for energy metabolism in animals.
No preview · Article · Feb 2006 · Veterinary Research Communications
[Show abstract][Hide abstract] ABSTRACT: Pleomorphic adenomas of the salivary gland were diagnosed in two dogs. The tumours were single, firm and well circumscribed, with a smooth cut surface. Metastatic tumours were not detected. Histopathological examination revealed that the tumours contained multiple cysts lined with luminal epithelial cells and myoepithelial cells, and mucinous, myxochondroid and cartilaginous tissues. Immunohistochemical examination demonstrated labelling of luminal epithelial cells and myoepithelial cells, and mucinous, myxochondroid and cartilaginous tissues with antibodies to cytokeratin LU-5, AE1/AE3, CK-14, CALP, a-SMA, vimentin, GFAP, and S-100. Labelling for GFAP indicated stromal transformation into myxoid and chondroid tissues.
No preview · Article · Feb 2006 · Journal of Comparative Pathology
[Show abstract][Hide abstract] ABSTRACT: Neuroendocrine (NE) carcinoma was diagnosed in 10 dogs. In six cases examined by cephalometric radiography and computerized tomography, a large mass was seen to fill the nasal cavity. Histopathologically, sheets, nests or ribbons of neoplastic cells were separated by delicate or thick fibrovascular stroma. The neoplastic cells were round, oval, or spindle-shaped; cytoplasmic granules and hyperchromatic nuclei with prominent nucleoli were present. Neoplastic cells were invariably immunohistochemically positive for cytokeratin (CK) AE1/AE3, neuron-specific enolase, chromogranin A and vasoactive intestinal polypeptide. Eight dogs were positive for S100 protein, seven for synaptophysin, five for protein gene product 9.5, two for somatostatin, and one for Leu-7. Immunolabelling gave negative results for CK 8, CK 19, calcitonin, calcitonin gene-related polypeptide, neurofilaments, serotonin, gastrin and glial fibrillary acidic protein. Ultrastructurally, the neoplastic cells contained a large number of round, membrane-bounded, densely-cored granules corresponding to neurosecretory granules. These observations were consistent with the neuroendocrine nature of the carcinomas.
No preview · Article · Aug 2005 · Journal of Comparative Pathology
[Show abstract][Hide abstract] ABSTRACT: Plasma metabolites and immunoreactive insulin (IRI) concentrations and enzyme activities of some types of peripheral leucocytes were measured to clarify one aspect of the differences in nutrient metabolism between dogs and cats. There were no significant differences in plasma concentrations of glucose, triglyceride, free fatty acids and IRI between dogs and cats. Higher total cholesterol and lower HDL cholesterol concentrations were observed in feline plasma, and H/T ratio (HDL/total cholesterol concentrations) was significantly lower than that in canine plasma. The cytosolic activities of fructokinase (FK), pyruvate kinase (PK), glucose-6-phosphate dehydrogenase (G6PD) and lactate dehydrogenase (LDH) were significantly higher and the activities of cytosolic malate dehydrogenase (MDH) and mitochondrial glutamate dehydrogenase (GLDH) were significantly lower in feline leucocytes than those in canine leucocytes. Higher activities of FK, PK and G6PD, which regulate the rate of biosynthesis of fatty acids, may reflect the different characteristics in nutrient metabolism in feline tissues from canine tissues.
No preview · Article · Mar 2005 · Research in Veterinary Science
[Show abstract][Hide abstract] ABSTRACT: The activities of the enzymes in the malate-aspartate shuttle were measured in peripheral leucocytes of spontaneous type 1 diabetic dogs and cats treated with insulin injections. In the diabetic dogs and cats, fasting plasma glucose concentrations were three- or fourfold greater than the control levels in spite of insulin injections and the activities of cytosolic malate dehydrogenase (MDH), one of pivotal enzymes in the malate-aspartate shuttle, were remarkably lower than the controls. Depressed expression of cytosolic MDH mRNA was confirmed by RT-PCR analysis in the diabetic animals. The cytosolic ratio of MDH/lactate dehydrogenase (LDH) activity (M / L ratio) in leucocytes of the diabetic animals was significantly lower than that of normal control animals. The smaller M / L ratio appeared to reflect depression of energy metabolism in the diabetic animals. Intrinsically lower and further decreased MDH activities may be factors that induce insulin resistance observed in diabetic cats.
No preview · Article · Mar 2005 · Research in Veterinary Science