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Effects of sprint training on extrarenal potassium regulation with intense exercise in Type 1 diabetes.
Harmer, AR, Ruell, PA, McKenna, MJ, Chisholm, DJ, Hunter, SK, Thom, JM, Morris, NR, Flack, JR
Journal of applied physiology (Bethesda, Md. : 1985). 2006;(1):26-34
Abstract
Effects of sprint training on plasma K+ concentration ([K+]) regulation during intense exercise and on muscle Na+-K+-ATPase were investigated in subjects with Type 1 diabetes mellitus (T1D) under real-life conditions and in nondiabetic subjects (CON). Eight subjects with T1D and seven CON undertook 7 wk of sprint cycling training. Before training, subjects cycled to exhaustion at 130% peak O2 uptake. After training, identical work was performed. Arterialized venous blood was drawn at rest, during exercise, and at recovery and analyzed for plasma glucose, [K+], Na+ concentration ([Na+]), catecholamines, insulin, and glucagon. A vastus lateralis biopsy was obtained before and after training and assayed for Na+-K+-ATPase content ([3H]ouabain binding). Pretraining, Na+-K+-ATPase content and the rise in plasma [K+] ([K+]) during maximal exercise were similar in T1D and CON. However, after 60 min of recovery in T1D, plasma [K+], glucose, and glucagon/insulin were higher and plasma [Na+] was lower than in CON. Training increased Na+-K+-ATPase content and reduced [K+] in both groups (P < 0.05). These variables were correlated in CON (r = -0.65, P < 0.05) but not in T1D. This study showed first that mildly hypoinsulinemic subjects with T1D can safely undertake intense exercise with respect to K+ regulation; however, elevated [K+] will ensue in recovery unless insulin is administered. Second, sprint training improved K+ regulation during intense exercise in both T1D and CON groups; however, the lack of correlation between plasma delta[K+] and Na+-K+-ATPase content in T1D may indicate different relative contributions of K+-regulatory mechanisms.
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2.
Prolonged exercise to fatigue in humans impairs skeletal muscle Na+-K+-ATPase activity, sarcoplasmic reticulum Ca2+ release, and Ca2+ uptake.
Leppik, JA, Aughey, RJ, Medved, I, Fairweather, I, Carey, MF, McKenna, MJ
Journal of applied physiology (Bethesda, Md. : 1985). 2004;(4):1414-23
Abstract
Prolonged exhaustive submaximal exercise in humans induces marked metabolic changes, but little is known about effects on muscle Na+-K+-ATPase activity and sarcoplasmic reticulum Ca2+ regulation. We therefore investigated whether these processes were impaired during cycling exercise at 74.3 +/- 1.2% maximal O2 uptake (mean +/- SE) continued until fatigue in eight healthy subjects (maximal O2 uptake of 3.93 +/- 0.69 l/min). A vastus lateralis muscle biopsy was taken at rest, at 10 and 45 min of exercise, and at fatigue. Muscle was analyzed for in vitro Na+-K+-ATPase activity [maximal K+-stimulated 3-O-methylfluorescein phosphatase (3-O-MFPase) activity], Na+-K+-ATPase content ([3H]ouabain binding sites), sarcoplasmic reticulum Ca2+ release rate induced by 4 chloro-m-cresol, and Ca2+ uptake rate. Cycling time to fatigue was 72.18 +/- 6.46 min. Muscle 3-O-MFPase activity (nmol.min(-1).g protein(-1)) fell from rest by 6.6 +/- 2.1% at 10 min (P <0.05), by 10.7 +/- 2.3% at 45 min (P <0.01), and by 12.6 +/- 1.6% at fatigue (P <0.01), whereas 3[H]ouabain binding site content was unchanged. Ca2+ release (mmol.min(-1).g protein(-1)) declined from rest by 10.0 +/- 3.8% at 45 min (P <0.05) and by 17.9 +/- 4.1% at fatigue (P < 0.01), whereas Ca2+ uptake rate fell from rest by 23.8 +/- 12.2% at fatigue (P=0.05). However, the decline in muscle 3-O-MFPase activity, Ca2+ uptake, and Ca2+ release were variable and not significantly correlated with time to fatigue. Thus prolonged exhaustive exercise impaired each of the maximal in vitro Na+-K+-ATPase activity, Ca2+ release, and Ca2+ uptake rates. This suggests that acutely downregulated muscle Na+, K+, and Ca2+ transport processes may be important factors in fatigue during prolonged exercise in humans.
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3.
Hypothalamic digoxin, hemispheric chemical dominance, and chronic bronchitis emphysema.
Kurup, RK, Kurup, PA
The International journal of neuroscience. 2003;(9):1241-58
Abstract
The isoprenoid pathway produces three key metabolites--endogenous digoxin (membrane sodium-potassium ATPase inhibitor, immunomodulator, and regulator of neurotransmitter/amino acid transport), dolichol (regulates N-glycosylation of proteins), and ubiquinone (free radical scavenger). This was assessed in patients with chronic bronchitis emphysema. The pathway was also assessed in patients with right hemispheric, left hemispheric, and bihemispheric dominance to find the role of hemispheric dominance in the pathogenesis of chronic bronchitis emphysema. All the 15 patients with chronic bronchitis emphysema were right-handed/left hemispheric dominant by the dichotic listening test. In patients with chronic bronchitis emphysema there was elevated digoxin synthesis, increased dolichol, and glycoconjugate levels, and low ubiquinone and elevated free radical levels. There was also an increase in tryptophan catabolites and a reduction in tyrosine catabolites. There was an increase in cholesterol:phospholipid ratio and a reduction in glycoconjugate levels of RBC membrane in patients with chronic bronchitis emphysema. The same biochemical patterns were obtained in individuals with right hemispheric dominance. Endogenous digoxin by activating the calcineurin signal transduction pathway of T-cell can contribute to immune activation in chronic bronchitis emphysema. Increased free radical generation can also lead to immune activation. Endogenous synthesis of nicotine can contribute to the pathogenesis of the disease. Altered glycoconjugate metabolism and membranogenesis can lead to defective lysosomal stability contributing to the disease process by increased release of lysosomal proteases. The role of an endogenous digoxin and hemispheric dominance in the pathogenesis of chronic bronchitis emphysema and in the regulation of lung structure/function is discussed. The biochemical patterns obtained in chronic bronchitis emphysema is similar to those obtained in left-handed/right hemispheric chemically dominant individuals by the dichotic listening test. But all the patients with chronic bronchitis emphysema were right-handed/left hemispheric dominant by the dichotic listening test. Hemispheric chemical dominance has no correlation with handedness or the dichotic listening test. Chronic bronchitis emphysema occurs in right hemispheric chemically dominant individuals and is a reflection of altered brain function. Hemispheric chemical dominance can play a role in the regulation of lung function and structure.
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4.
Hypothalamic digoxin, hemispheric chemical dominance, and inflammatory bowel disease.
Kurup, RK, Kurup, PA
The International journal of neuroscience. 2003;(9):1221-40
Abstract
The isoprenoid pathway produces three key metabolites--endogenous digoxin, dolichol, and ubiquinone. It was considered pertinent to assess the pathway in inflammatory bowel disease (ulcerative colitis and regional ileitis). Since endogenous digoxin can regulate neurotransmitter transport, the pathway and the related cascade were also assessed in individuals with differing hemispheric dominance to find out the role of hemispheric dominance in its pathogenesis. All the patients with inflammatory bowel disease were right-handed/left hemispheric dominant by the dichotic listening test. The following parameters were measured in patients with inflammatory bowel disease and in individuals with differing hemispheric dominance: (1) plasma HMG CoA reductase, digoxin, dolichol, ubiquinone, and magnesium levels; (2) tryptophan/tyrosine catabolic patterns; (3) free-radical metabolism; (4) glycoconjugate metabolism; and (5) membrane composition and RBC membrane Na+-K+ ATPase activity. Statistical analysis was done by ANOVA. In patients with inflammatory bowel disease there was elevated digoxin synthesis, increased dolichol and glycoconjugate levels, and low ubiquinone and elevated free radical levels. There was also an increase in tryptophan catabolites and a reduction in tyrosine catabolites. There was an increase in cholesterol:phospholipid ratio and a reduction in glycoconjugate level of RBC membrane in these groups of patients. Inflammatory bowel disease is associated with an upregulated isoprenoid pathway and elevated digoxin secretion from the hypothalamus. This can contribute to immune activation, defective glycoprotein bowel antigen presentation, and autoimmunity and a schizophreniform psychosis important in its pathogenesis. The biochemical patterns obtained in inflammatory bowel disease is similar to those obtained in left-handed/right hemispheric dominant individuals by the dichotic listening test. But all the patients with peptic ulcer disease were right-handed/left hemispheric dominant by the dichotic listening test. Hemispheric chemical dominance has no correlation with handedness or the dichotic listening test. Inflammatory bowel disease occurs in right hemispheric chemically dominant individuals and is a reflection of altered brain function.
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5.
Endotoxemia stimulates skeletal muscle Na+-K+-ATPase and raises blood lactate under aerobic conditions in humans.
Bundgaard, H, Kjeldsen, K, Suarez Krabbe, K, van Hall, G, Simonsen, L, Qvist, J, Hansen, CM, Moller, K, Fonsmark, L, Lav Madsen, P, et al
American journal of physiology. Heart and circulatory physiology. 2003;(3):H1028-34
Abstract
We assessed the hypothesis that the epinephrine surge present during sepsis accelerates aerobic glycolysis and lactate production by increasing activity of skeletal muscle Na(+)-K(+)-ATPase. Healthy volunteers received an intravenous bolus of endotoxin or placebo in a randomized order on two different days. Endotoxemia induced a response resembling sepsis. Endotoxemia increased plasma epinephrine to a maximum at t = 2 h of 0.7 +/- 0.1 vs. 0.3 +/- 0.1 nmol/l (P < 0.05, n = 6-7). Endotoxemia reduced plasma K(+) reaching a nadir at t = 5 h of 3.3 +/- 0.1 vs. 3.8 +/- 0.1 mmol/l (P < 0.01, n = 6-7), followed by an increase to placebo level at t = 7-8 h. During the declining plasma K(+), a relative accumulation of K(+) was seen reaching a maximum at t = 6 h of 8.7 +/- 3.8 mmol/leg (P < 0.05). Plasma lactate increased to a maximum at t = 1 h of 2.5 +/- 0.5 vs. 0.9 +/- 0.1 mmol/l (P < 0.05, n = 8) in association with increased release of lactate from the legs. These changes were not associated with hypoperfusion or hypoxia. During the first 24 h after endotoxin infusion, renal K(+) excretion was 27 +/- 7 mmol, i.e., 58% higher than after placebo. Combination of the well-known stimulatory effect of catecholamines on skeletal muscle Na(+)-K(+)-ATPase activity, with the present confirmation of an expected Na(+)-K(+)- ATPase-induced decline in plasma K(+), suggests that the increased lactate release was due to increased Na(+)-K(+)-ATPase activity, supporting our hypothesis. Thus increased lactate levels in acutely and severely ill patients should not be managed only from the point of view that it reflects hypoxia.
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6.
Endogenous hypodigoxinemia-related immune deficiency syndrome.
Kurup, RK, Kurup, PA
The International journal of neuroscience. 2003;(9):1287-303
Abstract
The isoprenoid pathway produces three key metabolites--digoxin (membrane Na+-K+ ATPase inhibitor, regulator of neurotransmitter transport, and an immunomodulatory agent), dolichol (a regulator of N-glycosylation of proteins), and ubiquinone (a free radical scavenger). The pathway was assessed in acute rheumatic fever patients with recurrent streptococcal infections, and who were also studied for differences in right and left hemispheric dominance. The isoprenoid pathway was downregulated with decreased digoxin synthesis in these patients and in those with left hemispheric chemical dominance. The tryptophan catabolites were decreased and the tyrosine catabolites increased. In these groups of patients the dolichol and glycoconjugate levels were reduced and lysosomal stability was increased. The ubiquinone levels were elevated and free radical levels decreased in these patients. The membrane cholesterol:phospholipid ratios were decreased and membrane glycoconjugates increased. On the other hand in right hemispheric chemical dominance the reverse patterns and hyperdigoxinemia with an upregulated isoprenoid pathway were noticed. The role of the isoprenoid pathway in the pathogenesis of acute rheumatic fever and recurrent streptococcal infections and its relation to hemispheric chemical dominance is discussed.
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7.
Modulation of Na, K-ATPase activity by immunoglobulins--III. Influence of an ATPase activity regulating agent "Marina" on Na, K-ATPase activity in patients with various chronic disturbances.
Ponomarenko, E, Pokrotnieks, J, Jirgensons, J, Seleznevs, J, Danilans, A, Shubnikova, N, Kalvins, I
Zhonghua yi xue za zhi = Chinese medical journal; Free China ed. 2001;(11):617-20
Abstract
BACKGROUND In some earlier work we have demonstrated that hypotonic mineral water can change the functional activity of Na, K-ATPase both in vitro and in vivo. The current investigation was aimed at measuring of the functional activity of ATPase in erythrocytes from blood samples of patients before and after treatment with the artificially mineralised water "Marina". METHODS "Marina"--an artificial mineral water containing K+ and Mg2+ ions, was investigated by double-blind method. Treatment lasted 7 days, daily intake of "Marina" was 4 x 200 ml before meals. Na, K-ATPase activity in erythrocytes and a number of clinical indices was determined before and after the treatment. RESULTS After the intake of the preparation "Marina" the normal activity pattern of the Na, K-ATPase in chronic active hepatitis or atherosclerosis patients was restored. The restoration of the Na, K-ATPase activity brought about the normalization of vital clinical indices. CONCLUSIONS The summarized data from the in vitro and in vivo experiments point to formation of Na, K-ATPase and immunoglobulin complexes as possible cause of cell disfunction and source of organic disturbances.