Metabolic effects of ouabain in the perfused rat heart

1964 ◽  
Vol 207 (2) ◽  
pp. 347-351 ◽  
Author(s):  
Robert A. Kreisberg ◽  
John R. Williamson
Keyword(s):  
Calcium Concentration ◽  
Specific Activity ◽  
Calcium Content ◽  
Metabolic Effects ◽  
Rat Hearts ◽  
High Calcium ◽  
High Calcium Concentration ◽  
Free Glucose ◽  
Steady State Levels ◽  
Perfusion Period

Ouabain increased the uptake and oxidation of glucose-U-C14 by perfused guinea pig and rat hearts by 50%. Cardiac glycogen content remained constant and no change in glycogen specific activity was observed. The metabolic changes produced by ouabain were dependent on the calcium concentration of the perfusate. Reduction of the calcium content of the perfusate by 50% abolished the increase in C14O2 production by ouabain. The C14O2 production of hearts perfused with buffer containing twice the physiological calcium concentration was similar to that of hearts perfused with buffer containing the normal calcium concentration and ouabain. The effect of the high calcium concentration combined with ouabain was not different from that produced by either one alone. Steady-state levels of glycolytic intermediates after a 30-min perfusion period were elevated in the absence of glycogenolysis and free glucose did not accumulate intracellularly. In so far as the changes in glucose metabolism are concerned the findings are consistent with the concept that the effects of glycosides on cardiac muscle are dependent on changes in calcium transport or concentration at the site of the contractile elements.

Phosphorylation of Ca-ATPase of Sarcoplasmic Reticulum with Different Substrates

1983 ◽  
Vol 38 (9-10) ◽  
pp. 845-847 ◽  
Author(s):  
Hector Barrabin ◽  
Leopoldo de Meis
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Low Temperatures ◽  
Hplc Analysis ◽  
Calcium Concentration ◽  
Specific Activity ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
High Calcium ◽  
High Calcium Concentration ◽  
Rate Limiting

ATP and GTP as substrate for phosphorylation of sarcoplasmic reticulum ATPase are compared. Maximal levels of phosphoenzyme are between 4.5 and 4.8 nmol per mg of protein when either substrate is used provided that phosphoenzyme hydrolysis are strongly inhibited by high calcium concentration (20 mм) and low temperatures ( 0 ° C ) . The maximal values obtained with GTP are lower than those previously reported. It is shown that this difference is due to underestimation of the specific activity of labeled nucleotides used in previous studies, as revealed by UV absorption and HPLC analysis. The dependence of the phosphoenzyme levels on calcium concentration, pH and temperature confirm previous findings indicating that ATP, but no GTP, accelerates the rate limiting step of the catalytic cycle.

INHIBITORY ACTION OF CALCIUM ON THE INACTIVATION OF ANTIDIURETIC HORMONE BY RAT KIDNEY SLICES

1963 ◽  
Vol 44 (4) ◽  
pp. 563-569 ◽  
Author(s):  
N. A. Thorn ◽  
N. B. S. Willumsen
Keyword(s):  
Arginine Vasopressin ◽  
Inhibitory Action ◽  
Calcium Concentration ◽  
Rat Kidney ◽  
Kidney Medulla ◽  
Marked Inhibition ◽  
High Calcium ◽  
Rational Explanation ◽  
High Calcium Concentration ◽  
Cellular Permeability

ABSTRACT Increasing the calcium concentration 5 times or more in the medium used for studying the inactivation of arginine-vasopressin by rat kidney medulla slices caused a marked inhibition of the inactivating activity of such slices. This effect was not found in homogenates of rat kidney medulla. The results are in agreement with the interpretation that the high calcium concentration decreased the cellular permeability to the hormone. This would seem to give a rational explanation of the vasopressin-resistant diabetes insipidus which is found in hypercalcaemia.

High Calcium Concentration in Water Increases Mortality of Salmon and Trout Eggs

1988 ◽  
Vol 50 (3) ◽  
pp. 129-135 ◽  
Author(s):  
H. George Ketola ◽  
D. Longacre ◽  
A. Greulich ◽  
L. Phetterplace ◽  
R. Lashomb
Keyword(s):  
Calcium Concentration ◽  
High Calcium ◽  
High Calcium Concentration

Calcium effect on fermentative hydrogen production in an anaerobic up-flow sludge blanket system

2006 ◽  
Vol 54 (9) ◽  
pp. 105-112 ◽  
Author(s):  
F.-Y. Chang ◽  
C.-Y. Lin
Keyword(s):  
Hydrogen Production ◽  
Production Efficiency ◽  
Calcium Concentration ◽  
Operating Conditions ◽  
Multinomial Regression ◽  
Fermentative Hydrogen Production ◽  
High Calcium ◽  
High Calcium Concentration ◽  
Calcium Effect ◽  
Fermentative Hydrogen

The effects of calcium ions on a granular fermentative hydrogen production system were investigated in four lab-scale UASB reactors that fed on sucrose (20 g COD/L). The reactors were seeded with anaerobic sewage sludge microflora and operated at a temperature of 35±1°, pH of 6.7 with hydraulic retention times (HRTs) of 24–6 h. The experimental results indicated that calcium ion addition (75∼150 mg/L) could enhance the granulation and elevate hydrogen production efficiency. However, an overly-high calcium concentration (300 mg-Ca+2/L) deteriorated the hydrogen productivity. A calcium concentration of 150 mg-Ca+2/L resulted in a peak HP of 3.6 mol H2/mol-sucrose and HPR of 807 mmol-H2/L-d at HRTs of 8 and 6 h, respectively. The EPS concentration of biohydrogenic biomass was higher than that of the aerobic or methanogenic biomass. The protein/carbon-ratio ranged from 0.17 to 0.26%. The multinomial regression analysis shows that the 75∼150 mg-Ca+2/L calcium concentrations and HRT of 6 h were the optimal operating conditions to efficiently produce hydrogen.

scholarly journals High calcium concentration in bones promotes bone metastasis in renal cell carcinomas expressing calcium-sensing receptor

2014 ◽  
Vol 13 (1) ◽  
pp. 42 ◽  
Author(s):  
Elke Joeckel ◽  
Tobias Haber ◽  
Dirk Prawitt ◽  
Kerstin Junker ◽  
Christian Hampel ◽  
...  
Keyword(s):  
Bone Metastasis ◽  
Renal Cell ◽  
Calcium Concentration ◽  
Calcium Sensing Receptor ◽  
Renal Cell Carcinomas ◽  
Calcium Sensing ◽  
High Calcium ◽  
High Calcium Concentration

Impact of High Calcium Concentration on Sulfate Scale Prediction at High Temperature from 120°C to 220°C

2018 ◽  
Author(s):  
Guannan Deng ◽  
Amy T. Kan ◽  
Zhaoyi Dai ◽  
Alex Y. Lu ◽  
Khadouja Harouaka ◽  
...  
Keyword(s):  
High Temperature ◽  
Calcium Concentration ◽  
High Calcium ◽  
High Calcium Concentration

HYPERPARATHYROIDISM AND PREGNANCY

1964 ◽  
Vol 47 (4) ◽  
pp. 549-564 ◽  
Author(s):  
Gorm Wagner ◽  
Ib Transbøl ◽  
Johannes C. Melchior
Keyword(s):  
Bone Disease ◽  
Calcium Concentration ◽  
Perinatal Death ◽  
Severe Disease ◽  
Indirect Evidence ◽  
Relative Number ◽  
Consecutive Series ◽  
Number Of Patients ◽  
High Calcium ◽  
High Calcium Concentration

ABSTRACT The obstetric and metabolic observations made in a woman suffering from hyperparathyroidism and her newborn infant are described. The significant findings were: 1) slight maternal hypercalcaemia, 2) a high calcium concentration in amniotic fluid, 3) a foetal hypercalcaemia greater than that in the mother, 4) a low serum calcium concentration during the first few weeks of life but no manifest tetany, 5) a higher than normal plasma alkaline phosphatase level in the newborn but no bone disease demonstrable by X-ray, and 6) a lower content of calcium in the mother's milk than in normal human milk. Pregnancy, labour and delivery were uneventful. A study of the literature comprising 23 females with a minimum of 34 pregnancies during their disease, shows that these females suffered from a more severe disease than 138 patients in a consecutive series of cases of hyperparathyroidism during about the same period (1930–1960). Since the relative number of patients with bone disease has decreased during the last 10–15 years we believe that the risks for perinatal death and tetany observed in this review, i. e. about 25 and 50 per cent, respectively, are greater than would be expected in a consecutive series today. A severe reduction in fertility is presumably not present. Labour and delivery are not interfered with, but there seems to be a tendency toward a low birth weight. Indirect evidence for renal damage and hypertension as the cause of stillbirth and neonatal death is given. Since no case of infantile osteitis fibrosa was observed it is concluded that the maternal parathyroid hormone does not pass freely through the placental barrier. The treatment is discussed.

Sign in / Sign up

Export Citation Format

Share Document