Changes in muscle, liver, and plasma free fatty acid levels in the pigeon on acute exposure to cold.

Adult pigeons were subjected to acute cold exposure (-25 degrees C; 30 min). Fully-plumed birds, showed a pronounced increase in the level of FFA in the blood, but not in the liver or muscle. Partially-defeathered (dorsum and pectoral regions) birds, likewise, showed a marked increase in plasma FFA level but failed to indicate any change in FFA levels in the liver or the muscle. It is concluded that even if the mobilized FFA may have supported calorigenic processes in the normothermic cold-exposed pigeon, lipid reserves are unlikely to have served as a significant source of energy for thermogenic functions in the hypothermic (defeathered) bird.     

The effect of exercise and restraint on pectoral muscle metabolism in pigeons

The effect of various activity regimes on metabolism of pigeon pectoralis was examined by measurement of blood lactate following exercise, total lactate dehydrogenase activity of pectoral muscle, and proportions of specific isoenzymes of pectoral muscle lactate dehydrogenase. Sprint-trained birds had the highest pectoral muscle lactate dehydrogenase activity (1409 IU · g⁻¹ wet tissue), while endurance-trained birds had the highest peak lactate levels (287 mg · dl⁻¹, extrapolated from decay curves) and fastest half-time of the lactate response (4.8 min) following exercise, but the lowest lactate dehydrogenase activity (115 IU · g⁻¹ wet tissue). Immobilization of one wing for 3 weeks following endurance training produced a marked increase in lactate dehydrogenase activity of the immobilized muscle, compared to that in the contralateral pectoralis and endurance-trained muscle. Aerobic forms of the lactate dehydrogenase enzyme (that favor conversion of lactate to pyruvate) predominated in pectoral muscle of endurance-trained birds, while cage-confined birds exhibited primarily the anaerobic isoenzymes. These results demonstrate that conversion of pectoral muscle lactate dehydrogenase isoenzymes, total lactate dehydrogenase activity, and half-time of lactate response after exercise is dependent on activity regime in pigeons. In this respect, pigeon pectoral muscle responds to training and disuse in a manner similar to that of mammalian skeletal muscle. Accepted: 10 September 1996     

Flight effects on plasma glucose, lactate, catecholamines and corticosterone in homing pigeons

Significant increase in the circulating levels of glucose, lactate, adrenaline (A) and noradrenaline (NA) was observed in homing pigeons after a flight of 48 km, lasting 60-80 min. There was, however, no change in plasma corticosterone concentrations. The increase in lactate has been attributed mainly to the activity of the white glycolytic fibres in the flight muscles. The increase in A and NA indicated increased sympathetic activity. It is suggested that the flight-induced increase in A stimulated the release of glucagon which could account for the increase in plasma glucose. The lack of any increase in plasma corticosterone implied that the birds were not under any serious stress during the flight and that these results represent the normal changes that may be expected in pigeons during a free flight of the specified distance and duration.     

Studying the influence of some reactive oxygen species on physical and chemical parameters of blood

The aim of this work was to estimate the dynamics of blood physical and chemical parameters when blood specimens were processed by singlet oxygen in vitro. Our experiments were executed with whole blood specimens of healthy people (n = 10). Each specimen was divided into five separate portions of 5 mL. The first portion was a control (without any exposures). The second one was processed by an oxygen-ozone mixture (at ozone concentration of 500 μg/L, the third portion by oxygen, and the fourth and fifth ones were processed by a gas mixture with singlet oxygen (50 and 100% of generator power). In blood samples after processing we studied the activity of lactate dehydrogenase, aldehyde dehydrogenase and superoxide dismutase, erythrocyte and plasma levels of glucose and lactate, acid-base balance and the partial pressure of gases in blood. It was found out, that blood processing by singlet oxygen leads to optimization of energy, detoxication and antioxidant enzymes functioning with changes in plasma and erythrocyte level of glucose and lactate, normalization of blood gases level and acid-base balance. Our results show, that the effect of singlet oxygen on enzyme activity is more pronounced than exposure to an oxygen-ozone gas mixture.     

Estimation of some molecular effects of gaseous nitrogen oxide on human blood in vitro

The aim of this work is complex estimation of the nitric oxide action on whole blood of healthy people. We tested the reaction of whole human blood (n = 14) to the processing of it with cold NO-containing plasma. We performed direct sparging of blood samples by gaseous flow with NO in a special plant. Cold NO-containing plasma was generated by apparatus “Plazon” (Russia). We tested lactate dehydrogenase activity in direct and reverse reactions, aldehyde dehydrogenase and superoxide dismutase activity, total protein and lactate level, acid-base balance and the partial pressure of gases in blood. For integral assessment of energy metabolism changes a number of derivative parameters (coefficients of energy reaction balance and substrate provision) were used. Our experiments showed that the processing of whole human blood with NO-containing gas flow (NO concentration — 800 ppm) results in significant changes of its physical and chemical parameters. This exposure leads to inhibition of erythrocytes energy metabolism, decreasing plasma antioxidant reserves, developing moderate ionic disorders and acid-base disbalance in blood samples in vitro.     

Metabolic adjustments of an air-breathing teleost, Channa maculata, to acute and prolonged exposure to hypoxic water

Plasma and tissue metabolite levels were measured in the air-breathing Channa maculata during acute and prolonged exposure to normoxic and hypoxic water. Exposure of the fish to hypoxic water (water oxygen partial pressure, PwO ₂= 50 mmHg) for 1 h caused increases in plasma glucose and lactate, liver and brain lactate, liver a-amino acid, heart and brain alanine and brain succinate levels. The metabolic changes in heart, brain and muscle could only be detected when Pw O₂ was 30 or 10 mmHg. Heart glycogen and liver lipid decreased during acute exposure. Prolonged exposure to hypoxic water ( Pw O₂= 30 mmHg) for 3 days caused an increase in plasma glycerol and liver lactate dehydrogenase activity, and a depletion of glycogen store in all tissues investigated. However, metabolite levels which had been elevated during acute hypoxic exposure were observed to return to their normoxic values after prolonged exposure. It was concluded that anaerobic metabolism was triggered by acute exposure to hypoxic water. Prolonged exposure to hypoxic water induced a metabolic readjustment involving mobilisation of lipid and glycogen stores, which is probably a reflection of the high metabolic load of aerial respiration imposed on the fish during exposure to hypoxic water.     

Effects of cold acclimation on the activity levels of creatine kinase, lactate dehydrogenase and lactate dehydrogenase isoenzymes in various tissues of the rat.

The effects of cold acclimation on the activity levels of creatine kinase, lactate dehydrogenase and lactate dehydrogenase isoenzymes in various tissues/ organs of the rat (Rattus norvegicus) were investigated. Male Sprague-Dawley rats were divided into two groups. One group was housed at 4+/-1 degrees C (experimental group) and the other at 24+/-1 degrees C (control group) for six months. The rats were housed in single cages and had access to food and water ad libitum. The tissues/organs investigated were heart, liver, lung, kidney, gastrocnemius muscle and interscapular brown adipose tissue as well as serum. With the exception of lung, (which showed a decrease of 24%) total creatine kinase activity levels were significantly increased (P< 0.05) in all the tissues/organs investigated (17-51%) as well as serum (34%), in cold acclimated animals. Cold acclimation also resulted in significantly increased (P< 0.05) activity levels of lactate dehydrogenase in all the tissues/organs investigated (14-24%) as well as serum (35%). Cold exposure resulted in an increase of the activity levels of all the detectable isoenzymes of lactate dehydrogenase, although not always significant, in all the tissues/organs investigated as well as serum. The M(4)tetramer of lactate dehydrogenase was the only detectable isoenzyme in serum.     

Effects of flight on blood parameters in homing pigeons

The influence of flight and flight duration on 13 blood parameters was studied in homing pigeons which returned after 2–22 h of flight from release sites 113–620 km away. The haematocrit value decreased from 54.4% in controls to 51.0% in the flown birds. A lowered haematocrit overproportionately improves blood flow. The plasma concentrations of glucose and l(+)-lactate did not differ between experimental and control birds. This is compatible with the idea that carbohydrates are utilized as fuel mainly in the initial phase of flight. Plasma free fatty acid levels were significantly increased during flight and triglyceride concentrations gradually decreased with progressive flight duration. These findings support the view that lipids are the main energy source during flight. Plasma uric acid concentrations were increased two- to fourfold in flown birds. Urea levels gradually rose with flight duration to 400% of controls. Plasma protein concentration was lowered in flown pigeons. These results hint to an increased protein degradation during flight. Na⁺, K⁺, Ca²⁺, and Mg²⁺ levels in the plasma of the flown pigeons were not significantly different from control values. This finding together with the urea/uric acid ratio indicates that no severe dehydration occurred in our pigeons during free-range flight.Abbreviations FA fatty acids - FFA free fatty acids     

The effect of prolonged exercise and in vivo treatment with ACTH and norepinephrine on plasma cortisol and on the levels of energy metabolites in liver, muscle and blood of the guinea pig (Cavia porcellus).

1. Exercise and in vivo treatment with adrenocorticotrophic hormone (ACTH) showed a marked tendency to increase in vivo plasma cortisol levels in the guinea pig (Cavia porcellus). 2. However, in vivo norepinephrine (NE) treatment did not have any notable effect on plasma cortisol levels. 3. Metabolite levels (glycogen, glycerol and lactate) in liver and plantaris and soleus muscle, and the levels of glucose, glycerol and lactate in blood, were determined in response to the same treatments. 4. A number of statistically significant changes, as well as certain trends, in metabolite levels were observed in response to the treatments and are discussed.     

Alterations in plasma-volume-corrected blood components of marathon runners and concomitant relationship to performance

The study was undertaken to determine the effects of running a marathon on concentration of various blood components resulting from phenomena other than fluid loss, and these were related to performance times. Twenty male marathon runners ranging from 20 to 50 years of age participated in the study. Blood samples were collected before and after the subjects ran in a marathon. Blood samples were analyzed for sodium, potassium, glucose, lactate dehydrogenase, creatinine, creatine phosphokinase, triglycerides, cholesterol, hematocrit, hemoglobin, protein, white blood cell number, uric acid, carbon dioxide, and iron. All of the blood parameters increased significantly in concentration with the exceptions of glucose and carbon dioxide which decreased. After accounting for plasma-volume loss (COR), there remained significant increases in blood serum lactate dehydrogenase, creatinine, creatine phosphokinase, uric acid, iron, and whole-blood white blood cell number. Significant decreases in COR serum sodium, protein, glucose, and carbon dioxide were found. Lactate dehydrogenase and creatine phosphokinase concentration changes support the concept of acute damage to muscle tissue resulting from marathon running. No strong relationship between performance time and other measured variables was found. COR measures were more representative of marathon induced blood changes from physiological dynamics other than plasma volume change than presently reported findings.     

Epinephrine, glucose, and lactate infusion in exercising adrenodemedullated rats

The purpose of this study was to determine the metabolic function of the marked increase in plasma epinephrine which occurs in fasted rats during treadmill exercise. Fasted adrenodemedullated (ADM) and sham-operated (SHAM) rats were run on a rodent treadmill (21 m/min, 15% grade) for 30 min or until exhaustion. ADM rats were infused with saline, epinephrine, glucose, or lactate during the exercise bouts. ADM saline-infused rats showed markedly reduced endurance, hypoglycemia, elevated plasma insulin, reduced blood lactate, and reduced muscle glycogenolysis compared with exercising SHAM's. Epinephrine infusion corrected all deficiencies. Glucose infusion restored endurance run times and blood glucose to normal without correcting the deficiencies in blood lactate and muscle glycogenolysis. Infusion of lactate partially corrected the hypoglycemia at 30 min of exercise, but endurance was not restored to normal and rats were hypoglycemic at exhaustion. We conclude that in the fasted exercising rat, actions of epinephrine in addition to provision of gluconeogenic substrate are essential for preventing hypoglycemia and allowing the rat to run for long periods of time.     

Exposure of silver carp (Hypophthalmichthys molitrix) to environmentally relevant levels of cadmium: hematology, muscle physiology, and implications for stock enhancement in the Xiangjiang River (Hunan, China)

Cadmium is a non-essential metal with a wide distribution that has severe toxic effects on aquatic animals. Changes in hematology and muscle physiology were examined in silver carp (Hypophthalmichthys molitrix) exposed to environmentally relevant levels of cadmium (0.01 mg L^?1) for 96 h. Cadmium exposure induced significant increases in the red blood cell count, and in the plasma concentrations of cortisol, glucose, and lactate. This suggests that the dose of cadmium was sufficient to cause stress, possibly associated with impaired gas exchange at the gills. There were no changes in hemoglobin concentration or plasma protein concentration. Significant decreases in muscle energy fuels (ATP and glycogen), and increases in muscle lactate persisted until the end of the exposure period, respectively. The changes in muscle lactate and protein in silver carp differed from those observed in response to exposure of fish to cadmium and heavy metals in other studies. The study highlights the importance of selecting unpolluted release sites with suitable water conditions for the survival of newly released individuals for stock enhancement of the Xiangjiang River.     

Changes in metabolite concentration in the plasma, liver and muscle of feed restricted Japanese quail exposed to cold.

Quail fed ad libitum and 50% ad libitum were cold exposed for several weeks, during time control quail remained at 21 degrees C. The concentration of plasma glucose, FFA, and uric acid, tissue glycogen and carcass fat content was measured at the end of the cold exposure period. Quail fed ad libitum showed no significant change in the levels of plasma and tissue metabolites, or the carcass fat content, following cold exposure. The feed consumption by the cold exposed quail increased, and the mean body weight showed little variation from that of the controls. Feed restricted quail which were cold exposed lost significantly more weight, and had a lower ranked fat content than their controls. Whereas feed restriction caused a lowering of the liver glycogen concentration in both treatment groups, muscle glycogen levels were higher than in quail fed ad libitum. However, cold exposure was not accompanied by a change in muscle and liver glycogen levels in feed restricted quail. Feed restricted quail at 21 degrees C were hypoglycaemic and hyperlipaemic compared to quail fed ad libitum, but cold exposed feed restricted quail had a much higher plasma glucose concentration than the controls. The ranked carcass fat content was inversely related to plasma FFA level in both control and cold exposed feed restricted quail. It is suggested that both a glycolytic and lipid mobilizing response to cold is obtained in quail whose body reserves are not spared from catabolism by adequate dietary nutrient absorption, and the possibility of gluconeogenesis from precursors produced by proteolysis is indicated.     

Effect of a 50 Hz electric field on plasma ACTH, glucose, lactate, and pyruvate levels in stressed rats

The effect of extremely low frequency electric field (EF) on stress induced changes of plasma ACTH, glucose, lactate, and pyruvate levels was examined in ovariectomized rats. The rats were exposed to 50 Hz EF (17500 V/m) for 60 min and were restrained for the latter half (30 min) of the EF exposure period. The restraint stress significantly increased the plasma ACTH and glucose levels (P <.05: Student's t test). Restraint induced increase of plasma ACTH and glucose levels tended to be suppressed by exposure to the EF. Meanwhile, the EF exposure also affected plasma lactate level. Thus, the EF exposure significantly decreases plasma lactate levels in the stressed rats (P <.05: Student's t test). Although the precise mechanisms in the restraint dependent alteration in plasma ACTH, glucose, lactate, and pyruvate levels are not fully understood, our results demonstrate that the 50 Hz EF alter both stress responses and energy metabolism in stressed rats.     

Activation of anaerobic metabolism in Biomphalaria glabrata (Mollusca: Gastropoda) experimentally infected by Angiostrongylus cantonensis (Nematoda,Metastrongylidae) by high-performance liquid chromatography

The activity of lactate dehydrogenase and the concentrations of glucose in the hemolymph and of glycogen in the digestive gland and cephalopedal mass of Biomphalaria glabrata experimentally infected with Angiostrongylus cantonensis were evaluated. Additionally, high performance liquid chromatography (HPLC) was used to determine the hemolymph concentrations of some carboxylic acids (oxalic, piruvic, lactic and succinic). After one, two and three weeks of infection, the snails were dissected to collect the hemolymph and separate the tissues. A significant reduction of the levels of glucose in the hemolymph was observed as of the first week of infection in relation to the control group. The lactate dehydrogenase activity of the infected group was significantly higher than the average of the control group. This increase was accompanied by a reduction of the levels of piruvic acid and an increase in the levels of lactic acid in the hemolymph of the parasited snails, confirming the acceleration of the anaerobic metabolism, necessary for the host to obtain energy and maintain its redox balance. In parallel, there was a decrease in the glycogen content of the storage tissues, with that reduction being significantly greater in the cephalopedal mass than the digestive gland, demonstrating that in this interaction system, the mobilization of glycogen was not sufficient to maintain and reestablish the normal glycemia of the infected snails.     

Acute cold exposure and the metabolism of glucose and some of its precursors in the liver of the fed and fasted sheep.

Measurements of total body oxygen consumption, visceral and hepatic blood flow, oxygen consumption, exchanges of amino acids, lactate, pyruvate and glucose were made on sheep fed 3--6 h or 21 h before the experiment and exposed for 3 h to a neutral environment (15 degrees C) or a cold environment (0.5 to 4 degrees C with clipped coat and wind speed 2 m.s-1). Recent feeding significantly increasedd the total oxygen consumption and the oxygen consumption of the viscera and liver. No general release of amino acids from the viscera or uptake by the liver after feeding was detected although the arterial plasma concentration of essential amino acids did increase significantly after feeding. The plasma concentration of most non-essential amino acids also increased except that of glycine, which decreased significantly. Cold exposure increased the total oxygen consumption and reduced the respiratory quotient significantly. Release of amino acids from the viscera was stimulated by cold exposure. There was a variable increase in the hepatic uptake of lactate and alanine when the sheep were fasted and cold-exposed. The liver's glucose output doubled and the blood (arterial) glucose concentration significantly increased in the cold.     

Acute stress response of Kootenai River white sturgeon Acipenser transmontanus Richardson reflected in peritoneal fluid and blood plasma

To evaluate whether stress-response indicators in blood plasma (BP) are similarly reflected in the peritoneal fluid (PF) white sturgeon Acipenser transmontanus were stressed by a 30 min air exposure and pH, PCO₂, osmolality, cortisol, glucose and lactate levels measured. Changes in certain stress indicators in the BP (pH, PCO₂, osmolality and glucose) also occurred in the PF, while stressor-induced changes in cortisol and lactate were restricted to the BP. Data suggest that PF is a modified ultrafiltrate of the blood and potentially a useful indicator of animal stress.     

In vitro influence of hormones on transport of glucose and glycogen in liver and muscle of pinealectomised pigeons, Columba livia Gmellin.

To substantiate the increased peripheral utilization of blood glucose by pineal in wild pigeons, an in vitro study on the ability of liver and muscle slices of intact and pinealectomised wild pigeons (C. livia) in terms of uptake and release of glucose, and deposition and depletion of glycogen, in presence of insulin, acetylcholine, glucagon and adrenaline has been undertaken. A total insensitivity of liver and muscle of pinealectomised birds for glycogen deposition and insensitivity of liver for glucose uptake has been observed. Increased glucose release from liver in response to adrenalin has been observed. The results are discussed in terms of involvement of pineal in metabolic regulation associated with breeding activities.