Comparison of enzyme activities in plasma and leukocytes in dairy and beef cattle

Concentrations of plasma glucose, immunoreactive insulin (IRI) and free fatty acid (FFA) and activities of enzymes related to energy metabolism and lactate dehydrogenase (LDH) isoenzyme pattern in plasma and leukocytes were investigated in lactating Holstein cows (dairy cattle) and fattening Japanese Black Wagyu x Holstein steers (beef cattle). IRI concentrations and LDH and malate dehydrogenase (MDH) activities in the plasma of beef cattle were significantly higher than those in dairy cattle. The cytosolic ratio of MDH/LDH activity in the leukocytes of beef cattle was significantly higher than that of dairy cattle. These findings might be associated with the different energy metabolism between dairy and beef cattle.     

Enzyme activities in some types of peripheral leukocytes of thoroughbred race horses before and after the races

Glucose, free fatty acid (FFA), triglyceride (TG) and immunoreactive insulin (IRI) concentrations in plasma and activities of enzymes related to energy metabolism in some types of peripheral leukocytes were measured in thoroughbred race horses before and after racing. Glucose, FFA, TG and IRI concentrations and enzyme activities did not change significantly in plasma. However, the activities of cytosolic hexokinase, malate dehydrogenase (MDH), mitochondrial MDH and aspartate aminotransferase decreased significantly in leukocytes of the horses after the races. The cytosolic ratio of MDH/LDH activity (ML ratio) in leukocytes decreased significantly after racing, and the ratio may be a useful indicator to evaluate energy metabolism in race horses.     

Thymoquinone enhances the activities of enzymes related to energy metabolism in peripheral leukocytes of diabetic rats

The aim of this study was to examine the effect of glycemic control using thymoquinone (TQ) on energy metabolism related enzymes in leukocytes of streptozotocin (STZ)-induced diabetic rats. The treatment of both TQ and insulin commenced 4 weeks after induction of diabetes. Plasma glucose, cholesterol and triglycerides levels were significantly reduced after TQ treatment, whereas immunoreactive insulin (IRI) showed significant increase. The activities of malate dehydrogenase (MDH) in cytosolic and mitochondrial fractions of peripheral blood leukocytes were significantly higher in rats treated with TQ and insulin as compared to that in diabetic controls. On the other hand the activities of lactic dehydrogenase (LDH) showed no significant changes between groups. ML ratio (cytosolic MDH/LDH specific activity ratio) was restored to those in the control rats. The results of this study demonstrate that TQ significantly increased insulin level and the activities of cytosolic and mitochondrial MDH in leukocytes of STZ-diabetic rats.     

Activities of enzymes in the malate-aspartate shuttle and the isoenzyme pattern of lactate dehydrogenase in plasma and peripheral leukocytes of lactating Holstein cows and riding horses

The activities of the enzymes involved in the malate-aspartate shuttle and lactate dehydrogenase (LDH) and the pattern of the isoenzymes of LDH were determined in plasma and peripheral leukocytes of lactating Holstein cows and thoroughbred riding horses as representative herbivorous animals. In the horse plasma, LDH activities were significantly lower and AST activities were significantly higher than those in the cow plasma. The specific activities of cytosolic malate dehydrogenase (MDH), LDH and AST in the horse leukocytes were higher than those in the cows. The cytosolic ratio of MDH/LDH activity (ML ratio) in the horse leukocytes was significantly lower than that in the cow leukocytes owing to significantly higher activities of LDH. The ML ratio was considered to reflect the difference in energy metabolism in leukocytes between cows and horses. The plasma LDH isoenzyme patterns of cow and horse showed the characteristic as herbivorous animals with dominance of LDH-1, -2 and -3. The LDH isoenzyme patterns with dominance of LDH-3 and -4 in the horse leukocytes were remarkably different from those in the cow leukocytes. There were significant differences in activities of malate-aspartate shuttle enzymes, ML ratio and LDH isoenzyme patterns in the cytosolic fractions of leukocytes between the lactating cows and the riding horses.     

Changes in metabolite, energy metabolism related enzyme activities and peripheral blood mononuclear cell (PBMC) Populations in beef heifers with two differing liveweight change profiles in New Zealand

Metabolite and immunoreactive insulin (IRI) concentrations, energy metabolism related enzymes activities and peripheral blood mononuclear cell (PBMC) populations were measured in blood of pregnant Angus heifers with differing liveweight change profiles (gaining or losing), in New Zealand to investigate the meanings of those parameters in the restricted feeding beef heifers. Beef heifers losing liveweight (−412 g/day) showed significantly lower concentrations of plasma IRI, and higher concentrations of plasma free fatty acid (FFA) than heifers gaining liveweight (483 g/day). The cytosolic and mitochondrial malate dehydrogenase (MDH) activities and MDH/lactate dehydrogenase (M/L) ratio in leukocytes of the liveweight losing heifers were significantly higher than those the liveweight gaining heifers. Percentages of cluster of differentiation (CD) 3 positive cells and natural killer (NK) cells in PBMC decreased significantly in the liveweight losing heifers compared to those in the liveweight gaining heifers. Plasma IRI and FFA concentrations, leukocyte cytosolic and mitochondrial MDH activities and CD3 positive and NK cell populations may be useful markers to evaluate metabolic conditions and immunity in the restricted feeding beef heifers.     

Changes in activities of enzymes related to energy metabolism in peripheral leukocytes of diabetic dogs with glycemic control by intensive insulin treatment

Changes in plasma glucose, immunoreactive insulin (IRI), and free fatty acids (FFA) concentrations and activities of enzymes related to energy metabolism in peripheral leukocytes were measured in type 1 diabetic dogs induced by streptozotocin administration before and after intensive insulin treatments. Before the insulin treatment, the plasma glucose concentrations were over 16.7 mmol/L and the activities of enzymes remarkably decreased in leukocytes of the diabetic dogs. In particular, malate dehydrogenase (MDH) activities decreased significantly. After glycemic control was achieved by insulin treatment, the plasma glucose concentrations were maintained between 6.8 and 7.7 mmol/L and the activities of enzymes restored to those in the control dogs. The changes in ML ratio (cytosolic MDH/lactate dehydrogenase specific activity ratio) reflected faithfully to metabolic conditions of animals and were considered to be a useful parameter to evaluate glycemic control and the effect of injected insulin in the diabetic dogs.     

Activities of enzymes in some types of peripheral leucocytes may reflect the differences in nutrient metabolism between dogs and cats

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.     

Activities of Enzymes in the Malate–Aspartate Shuttle in the Peripheral Leukocytes of Dogs and Cats

The activities of the enzymes involved in the malate–aspartate shuttle and the expression of malate dehydrogenase (MDH), a rate-limiting enzyme in the NADH shuttle that produces ATP in glucose metabolism in leukocytes, were determined to investigate the differences in this shuttle system in the peripheral leukocytes of dogs and cats. There were no significant differences between dogs and cats in plasma glucose, immunoreactive insulin, free fatty acid or triglyceride concentrations. The activities of cytosolic and mitochondrial MDH and of mitochondrial glutamate dehydrogenase (GLDH) in canine leukocytes were significantly higher than in feline leukocytes. High activities of MDH in canine leukocytes were confirmed by RT-PCR analysis on the total RNA extracted from leukocytes. It was concluded that there were significant differences between dogs and cats in the NADH shuttle system.     

Cytosolic ratio of malate dehyrogenase/lactate dehydrogenase activity in peripheral leukocytes of race horses with training

The activities of the enzymes involved in the malate-aspartate shuttle and m RNA expression of malate dehydrogenase (MDH), a crucial enzyme for the NADH shuttle that produces ATP in glucose metabolism in the peripheral leukocytes of horses, were measured to investigate the change in metabolic states with training. There were no significant differences in plasma glucose and immunoreactive insulin concentrations between race horses and riding horses, used as a comparable reference. The cytosolic and mitochondrial MDH activities in leukocytes of race horses were significantly higher than those of riding horses. High activities of MDH in leukocytes of race horses were confirmed by RT - PCR analysis on the total RNA extracted from the whole blood. The cytosolic ratio of MDH /lactate dehydrogenase (LDH) activity (M/L ratio) in leukocytes of race horses was significantly higher than in those of riding horses. Increase in the M/L ratio was considered to reflect elevation of energy metabolism in animal tissues. The M/L ratio may be a useful parameter to evaluate the difference in metabolic states between race horses and riding horses.     

The Activity Ratio of the Cytosolic MDH/LDH and the Isoenzyme Pattern of LDH in the Peripheral Leukocytes of Dogs,Cats and Rabbits

The activities of malate dehydrogenase (MDH) and lactate dehydrogenase (LDH) and the pattern of the isoenzymes of LDH were determined in the peripheral blood leukocytes of dogs, rabbits and cats. Rabbits had significantly higher plasma glucose concentrations than dogs or cats. Feline leukocytes showed higher LDH and lower MDH activities than canine or rabbit leukocytes. The M/L ratio, defined as the MDH activity divided by the LDH activity in cytosolic fractions, was considered to be a good indicator with which to evaluate the metabolic state in animal tissues. The M/L ratio was highest in canine and lowest in feline leukocytes. LDH-2 and LDH-3 isoenzymes were dominant in canine leukocytes. LDH-1 and LDH-2 were dominant in rabbit leukocytes, whereas LDH-5 was dominant in feline leukocytes. It was evident that there were significant differences in energy metabolism between the leukocytes of dogs, rabbits and cats.     

Malate dehydrogenase activities are lower in some types of peripheral leucocytes of dogs and cats with type 1 diabetes mellitus

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.     

Effect of supplementation of Agaricus mushroom meal extracts on enzyme activities in peripheral leukocytes of calves

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.     

Comparison of plasma metabolite concentrations and enzyme activities in beef cattle raised by different feeding systems in Korea, Japan and New Zealand

Concentrations of metabolites and immunoreactive insulin (IRI) and activities of enzymes related to energy metabolism were measured in plasma of Korean and Japanese beef cattle, which were raised by the indoor feeding system programmed to feed larger amount of roughage in their growing periods and larger amount of concentrate diet in their finishing periods (Japanese feeding system), and grazing New Zealand beef cattle. By the Japanese beef grading system, Korean and Japanese beef cattle showed high beef quality score, average grade 3.3 and 3.6, respectively. The plasma free fatty acid and lactate concentrations and lactate dehydrogenase (LDH), malate dehydrogenase (MDH) and aspartate aminotransferase (AST) activities in Korean beef cattle were significantly higher than those in Japanese beef cattle. The plasma lactate concentration in Korean beef cattle was 8.40 mmol/l, which was similar to the values observed in lactic acidosis. The higher activities of plasma LDH, MDH and AST may indicate slight liver damage by slightly acidotic conditions in Korean beef cattle. New Zealand beef cattle fed on pasture which they harvest by grazing showed significantly lower plasma glucose, cholesterol, lactate and IRI concentrations and enzyme activities than those in Korean and Japanese beef cattle fed on larger amount of concentrate diets. Plasma metabolite concentrations and energy metabolism-related enzyme activities may be good indicators for evaluating metabolic conditions of beef cattle raised by different feeding systems.     

Decrease in malate dehydrogenase activities in peripheral leucocytes of type 1 diabetic dogs

The activities of the enzymes involved in the malate-aspartate shuttle were measured in peripheral leucocytes of dogs with type 1 diabetes mellitus. In the diabetic dogs, fasting plasma glucose concentrations were twofold greater than control levels despite insulin injections and the activities of malate dehydrogenase (MDH), which plays a crucial role in the malate-aspartate shuttle, were decreased remarkably. The cytosolic ratio of MDH/lactate dehydrogenase (LDH) activity (M/L ratio) in leucocytes of the diabetic dogs was significantly lower than that of normal control dogs. The decrease of the M/L ratio appeared to reflect depression of energy metabolism in leucocytes of the diabetic dogs. The M/L ratio may be a useful parameter to evaluate metabolic conditions in diabetic dogs.     

Effect of castration at 10 months of age on growth physiology and behavior of male feral beef cattle

This study compared the growth performance, plasma testosterone and cortisol levels around castration at 10 months of age, and plasma insulin‐like growth factor (IGF)‐I concentration and flight speed, in intact bulls and steers from 10 to 21 months of age in a feral Spanish breed. Fourteen bulls (366.5 ± 48.5 kg live weight) were assigned at random to one of two treatments: surgically castrated (steers) or intact (bulls), and submitted to an identical fattening period. Steers reared until heavy live weights (21 months of age) grew slowly and had lower plasma IGF‐I concentrations than intact bulls. These differences were mainly highlighted the month after surgery (11 months of age) and the last part of the fattening period (from 19 to 21 months of age). After surgical castration (11 and 12 months of age), steers showed a tendency to display greater flight speed values than intact bulls but baseline plasma cortisol concentration did not differ between groups at this time. At the end, steers and bulls reached nearly similar temperament, as flight speed did not differ between them. The results confirm the role of IGF‐I as a key anabolic hormone in male beef cattle and thus it may reflect growth differences due to altered sex steroids production.     

Changes in activities of enzymes related to malate-aspartate shuttle in leukocytes from dogs given a herb supplement.

Changes in activities of enzymes related to the malate-aspartate shuttle were measured in leukocytes (WBC) from dogs given food supplemented with 2 mg/kg of herb powder, Echevaria glauca, every day for 4 weeks. There were no significant differences in plasma concentrations of glucose, immunoreactive insulin, free fatty acids and triglyceride between dogs given food with or without the herb supplementation. Activities of malate dehydrogenase (MDH) and aspartate aminotransferase (AST) in the malate-aspartate shuttle increased remarkably in mitochondria of WBC from dogs fed the herb supplementation. It is suggested that Echevaria glauca herb supplementation might activate NADH shuttle systems and mitochondrial energy metabolism in dogs.     

Comparison of insulin signaling gene expression in insulin sensitive tissues between cats and dogs

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-85α 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-85α 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.     

Changes in hepatic enzyme activities in transgenic mice carrying human prototype c-Ha-ras gene treated with diethylnitrosamine

Activities of malate dehydrogenase (MDH) and aspartate aminotransferase in the malate-aspartate shuttle were significantly increased in the cytosolic fractions of livers with early neoplastic symptoms such as swelling and discoloration in transgenic mice carrying the prototype human c-Ha-ras gene, Tg-rasH2 mice, which were administered with diethylnitrosamine (DEN) as a carcinogenic chemical at a dose of 200 mg/kg body weight. Cytosolic MDH/LDH (lactate dehydrogenase) (ML) ratio increased significantly and was considered to be a useful marker to characterize the energy metabolism at early neoplastic stage in livers of the Tg-rasH2 mice.     

Basal levels and responses to glucose infusion of plasma glucose and insulin in beef steer before and after the end of the growing phase on pasture

We examined the effect of grazing during the growing phase on plasma glucose and insulin behavior at the end of the growing phase and at the early stage of the subsequent fattening phase in beef steers. From 13 to 45 weeks of age (growing phase), crossbred beef steers were grazed with minimal supplement (group G: n = 5) or housed while being fed on hay and concentrate (group H: n = 5). Following this phase, both groups were housed for finishing (fattening phase). At the end of the growing phase, group G showed faster plasma glucose disappearance after intravenous glucose infusion, with a smaller plasma insulin response, compared with group H. At the third week of the fattening phase, group G still showed higher glucose tolerance, although they experienced abrupt changes in nutritional and environmental factors. The results suggest that grazing during the growing phase probably improves the glucose tolerance and insulin response to glucose infusion in steers compared with animals that were housed during the corresponding period, and the improved properties may persist at least a few weeks after the commencement of fattening.