scholarly journals Labeling of the releasable adenine nucleotides of washed human platelets

Blood ◽  
1977 ◽  
Vol 49 (1) ◽  
pp. 89-99 ◽  
Author(s):  
HJ Reimers ◽  
MA Packham ◽  
JF Mustard
Keyword(s):  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Energy Charge ◽  
Human Platelets ◽  
Transport Processes ◽  
Adenylate Energy Charge ◽  
Prolonged Incubation ◽  
Atp Pool ◽  
Adenine Nucleotide Pool

In rabbit platelets, the metabolically active ATP pool equilibrates with the releasable ATP pool within 1 day. The studies showing this have now been extended to human platelets. Human platelets labeled with 14C-adenosine or 14C-adenine were incubated for up to 10 hr in vitro at 37 degrees C. After 10 hr, about 12% of the total platelet 14C-ATP and 14C-ADP had become releasable with thrombin (4.2 units/ml). Lysis of platelets did not occur, since less than 1% of the platelet-bound 51Cr from platelets labeled with this radioisotope appeared in the ambient fluid upon thrombin treatment. The 14C-ATP/14C-ADP ratio of the released adenine nucleotides (7.6) was similar to the 14C-ATP/14C-ADP ratio of the nonreleasable adenine nucleotides (7.1) 2 hr after the labeling with 14C-adenosine. However, upon prolonged incubation (10 hr) in vitro, the 14C-ATP/14C-ADP ratio of the releasable adenine nucleotides decreased to 2.7. The adenylate energy charge and the 14C- ATP/14C-ADP ratio of the metabolic adenine nucleotide pool did not change significantly during the time of observation. The 14C-ATP content of the platelets decreased by less than 1% hr of incubation at 37 degrees C. These observations are interpreted to mean that the 14C is transferred from the metabolically active, nonreleasable adenine nucleotide pool of human platelets into the releasable adenine nucleotide pool as ATP and is partially hydrolyzed there to yield ADP. The transfer of ATP across the storage organelle membrane of platelets may be similar to transport processes in the chromaffin cells of the adrenal medulla and may represent a general phenomenon in cells that possess storage organelles containing adenine nucleotides.

scholarly journals Labeling of the releasable adenine nucleotides of washed human platelets

Blood ◽  
1977 ◽  
Vol 49 (1) ◽  
pp. 89-99 ◽  
Author(s):  
HJ Reimers ◽  
MA Packham ◽  
JF Mustard
Keyword(s):  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Energy Charge ◽  
Human Platelets ◽  
Transport Processes ◽  
Adenylate Energy Charge ◽  
Prolonged Incubation ◽  
Atp Pool ◽  
Adenine Nucleotide Pool

Abstract In rabbit platelets, the metabolically active ATP pool equilibrates with the releasable ATP pool within 1 day. The studies showing this have now been extended to human platelets. Human platelets labeled with 14C-adenosine or 14C-adenine were incubated for up to 10 hr in vitro at 37 degrees C. After 10 hr, about 12% of the total platelet 14C-ATP and 14C-ADP had become releasable with thrombin (4.2 units/ml). Lysis of platelets did not occur, since less than 1% of the platelet-bound 51Cr from platelets labeled with this radioisotope appeared in the ambient fluid upon thrombin treatment. The 14C-ATP/14C-ADP ratio of the released adenine nucleotides (7.6) was similar to the 14C-ATP/14C-ADP ratio of the nonreleasable adenine nucleotides (7.1) 2 hr after the labeling with 14C-adenosine. However, upon prolonged incubation (10 hr) in vitro, the 14C-ATP/14C-ADP ratio of the releasable adenine nucleotides decreased to 2.7. The adenylate energy charge and the 14C- ATP/14C-ADP ratio of the metabolic adenine nucleotide pool did not change significantly during the time of observation. The 14C-ATP content of the platelets decreased by less than 1% hr of incubation at 37 degrees C. These observations are interpreted to mean that the 14C is transferred from the metabolically active, nonreleasable adenine nucleotide pool of human platelets into the releasable adenine nucleotide pool as ATP and is partially hydrolyzed there to yield ADP. The transfer of ATP across the storage organelle membrane of platelets may be similar to transport processes in the chromaffin cells of the adrenal medulla and may represent a general phenomenon in cells that possess storage organelles containing adenine nucleotides.

Hepatotrophic effects of insulin on glucose, glycogen, and adenine nucleotides in hepatocytes isolated from fed adult rats

1980 ◽  
Vol 58 (10) ◽  
pp. 1004-1011 ◽  
Author(s):  
Khursheed N. Jeejeebhoy ◽  
Joseph Ho ◽  
Rajni Mehra ◽  
Alan Bruce-Robertson
Keyword(s):  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Energy Charge ◽  
Close Correlation ◽  
Adult Rats ◽  
Fed State ◽  
Adenine Nucleotide Pool ◽  
Intracellular Glucose

In vivo observations have suggested that there is an hepatotrophic effect of insulin. By contrast, subsequent in vitro work, using the isolated perfused liver system, showed no effect or indeterminate effects of insulin on the transport of glucose into the hepatocyte. However because this system may not have endured long enough to show such an influence we explored the transport of glucose using a 48-h suspension culture of hepatocytes isolated from young adult fed rats, the suspension being infused continuously with insulin at a rate approximating the maximum entering portal blood in the fed state. (In a separate study phloridzin was added after 2 h of incubation.) DNA, intracellular glucose and its inward transport, glycogen, and the adenine nucleotides were measured at intervals. By comparison with control or untreated cells, insulin-treated cells showed significantly more DNA and intracellular glucose, and the differences were abolished by phloridzin. Glucose transport rates fell to low values in untreated controls and still lower with insulin plus phloridzin. but the initial rate was maintained to the end (48 h) by insulin alone. Results for glycogen were similar to those for intracellular glucose. There was a close correlation (r = 0.96) between these two. The total adenine nucleotide pool and the concentration of ATP were maintained for about 24 h and fell to half their initial values by 48 h. Insulin had increased these concentrations significantly by 6 h. Although concentrations of ADP and AMP decreased gradually in all groups of cells, insulin enhanced the level of ADP by 12 h but had no measurable effect on that of AMP. The energy charge increased slightly throughout incubation but more so (by 6 h) in the presence of insulin. In conclusion the data support the concept that in the longer term (> 12 h) insulin in the portal circulation maintains the characteristic free permeability of the hepatocyte to glucose and this permits a variety of effects related to glucose entry into the hepatocyte.

Effects of Glyoxylate on Adenine Nucletodies and Aggregation of Human Platelets

1975 ◽  
Author(s):  
H. Holmsen ◽  
C. A. Setkowsky ◽  
H. J. Day
Keyword(s):  
Adenine Nucleotide ◽  
Energy Charge ◽  
Krebs Cycle ◽  
Lactate Production ◽  
Human Platelets ◽  
Adenylate Energy Charge ◽  
Atp Levels ◽  
Extracellular Glucose ◽  
Adenine Nucleotide Pool ◽  
Na Uptake

Glyoxylate (G) reduces the ATP/ADP ratio and the adenine nucleotide pool in Ascites tumor cells, probably through inhibition of Krebs cycle and accumulation of citrate (JBC 246, 1607 1971). Incubation of human platelets in plasma or after gelfiltration with G reduced the level of metabolic ATP with a corresponding accumulation of hypoxanthine within the first 10 min after which no changes took place. The decrease in ATP levels is noticeable above 15 mM and is maximal (60–75% decrease) at 45 mM G. Oligomycin, antimycin A (AA), pyruvate, succinate, aspartate or glutamate did not alter the effect of G; 2-deoxyglucose (2-DG) and absence of extracellular glucose enhanced the G-induced reduction in ATP levels. Lactate production was not altered by 45 mM G. The same degree of ATP reduction was observed in the absence and presence of extracellular Na indicating that G did not cause depletion of the adenine nucleotide pool by activating the Na-dependent platelet AMP deaminase through increased Na uptake. The adenylate energy charge (AEC) remained constant (0.89–0.93) despite the large fall in the ATP levels. Primary and secondary platelet aggregation also remained unaffected by G-induced reduction of the ATP levels. Incubation with 2-DG plus AA reduced both ATP levels and AEC, with complete abolishment of secondary and primary aggregation at AEC lower than 0.85 and 0.80, respectively. Although the mechanism whereby G reduces the levels of metabolic ATP remains obscure, these experiments demonstrate clearly that the platelets’ ability to undergo primary and secondary aggregation does not correlate with the level of metabolic ATP, but may correlate with AEC.(Supported by NIH Grant HL 14217–05.)

Hepatic preconditioning preserves energy metabolism during sustained ischemia

2000 ◽  
Vol 279 (1) ◽  
pp. G163-G171 ◽  
Author(s):  
C. Peralta ◽  
R. Bartrons ◽  
L. Riera ◽  
A. Manzano ◽  
C. Xaus ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Energy Charge ◽  
High Energy ◽  
Energetic Cost ◽  
Main Role ◽  
Adenylate Energy Charge ◽  
Glycogen Depletion ◽  
Adenine Nucleotide Pool

We evaluated the possibility that ischemic preconditioning could modify hepatic energy metabolism during ischemia. Accordingly, high-energy nucleotides and their degradation products, glycogen and glycolytic intermediates and regulatory metabolites, were compared between preconditioned and nonpreconditioned livers. Preconditioning preserved to a greater extent ATP, adenine nucleotide pool, and adenylate energy charge; the accumulation of adenine nucleosides and bases was much lower in preconditioned livers, thus reflecting slower adenine nucleotide degradation. These effects were associated with a decrease in glycogen depletion and reduced accumulation of hexose 6-phosphates and lactate. 6-Phosphofructo-2-kinase decreased in both groups, reducing the availability of fructose-2,6-bisphosphate. Preconditioning sustained metabolite concentration at higher levels although this was not correlated with an increased glycolytic rate, suggesting that adenine nucleotides and cAMP may play the main role in the modulation of glycolytic pathway. Preconditioning attenuated the rise in cAMP and limited the accumulation of hexose 6-phosphates and lactate, probably by reducing glycogen depletion. Our results suggest the induction of metabolic arrest and/or associated metabolic downregulation as energetic cost-saving mechanisms that could be induced by preconditioning.

Phospholipid and adenine nucleotide metabolism in muscle after burn injury

1985 ◽  
Vol 249 (5) ◽  
pp. R603-R610
Author(s):  
J. Turinsky ◽  
I. H. Chaudry
Keyword(s):  
Burn Injury ◽  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Energy Charge ◽  
Nucleotide Metabolism ◽  
Adenylate Energy Charge ◽  
Adenine Nucleotide Metabolism ◽  
Limb Muscles ◽  
32P Incorporation

The role of phospholipid and adenine nucleotide metabolism in postburn unresponsiveness of muscle to insulin was examined. A single hindlimb scald in the rat was produced, and 3 days later soleus muscles were incubated in vitro with and without insulin. Under basal conditions muscles from the burned limbs had normal contents of phosphatidylcholine and phosphatidylinositol but decreased diphosphatidylglycerol (-39%) and phosphatidylethanolamine (-24%) and increased sphingomyelin (+62%), lysophosphatidylcholine (+68%), and phosphatidylserine (+13%) compared with the contralateral unburned limb. Such muscle also incorporated 107-396% more [32P]phosphate into all measured phospholipids, except for diphosphatidylglycerol. The presence of insulin had no effect on either the mass of phospholipids or 32P incorporation in any muscle. The burned limb muscles (frozen in situ) also exhibited lower levels of ATP (-25%) and total adenine nucleotides (-24%) than uninjured muscle but normal adenylate energy charge. The burned limb muscles had lower adenosine (-37%), but inosine and hypoxanthine were 82 and 39% higher, respectively. These data suggest recovery of muscle from local thermal injury is associated with alterations in mass, and possibly also turnover, of tissue phospholipids, the measured phospholipids do not mediate the postreceptor action of insulin in normal muscle, energy charge of the recovering injured muscle is restored before ATP level at the time when this muscle is unresponsive to insulin stimulation.

scholarly journals Acquired granular pool defect in stored platelets

Blood ◽  
1981 ◽  
Vol 57 (2) ◽  
pp. 203-208
Author(s):  
AK Rao ◽  
S Niewiarowski ◽  
S Murphy
Keyword(s):  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Energy Charge ◽  
Adenylate Energy Charge ◽  
Platelet Factor ◽  
Final Volume ◽  
Before And After ◽  
Functional Defect ◽  
Metabolic Pool ◽  
The Mean

Platelets stored as concentrates (PC) for 72 h at 22 degrees C develop a functional defect. Alterations in adenine nucleotides of platelets have been shown to affect platelet function. Adenine nucleotide content of platelets was measured before and after storage and a decrease of 27.1 /+- 1.7% (mean /+- SE) in ATP and 39.1 /+- 2.6% in ADP were found in 34 PC stored with final volume of 50 ml. In 11 PC with 30 ml volume. ATP and ADP decreased by 39.4 /+- 3.2% and 49.4 /+- 2.1%, respectively. The mean ATP to ADP ratio of stored platelets was significantly higher than of fresh platelets in both groups, suggesting a relatively greater decrease in granular than metabolic pool nucleotides. Levels of low affinity platelet factor 4 measured by radioimmunoassay in plasma from 0.86 /+- 0.08 microgram/ml in the fresh PC to 8.59 /+- 0.39 microgram/ml in stored PC, indicating a concomitant alpha-granular secretion. Labeling of metabolic pool with 14C-adenine revealed a mean decrease in the adenylate energy charge of 2.0 /+- 0.4% in 12 of 16 stored PC, with a lower ATP and higher hypoxanthine labeling in stored as compared to fresh platelets. These observations suggest that stored platelets develop an acquired defect in both dense and alpha granules and in their ability to maintain ATP homeostasis.

Contracture of isolated rat heart cells on anaerobic to aerobic transition

1982 ◽  
Vol 242 (6) ◽  
pp. H1022-H1030 ◽  
Author(s):  
C. Hohl ◽  
A. Ansel ◽  
R. Altschuld ◽  
G. P. Brierley
Keyword(s):  
Rat Heart ◽  
Adenine Nucleotide ◽  
Energy Charge ◽  
Creatine Phosphate ◽  
Isolated Rat Heart ◽  
Heart Cells ◽  
Adenylate Energy Charge ◽  
Adult Rat ◽  
Oxygen Paradox ◽  
Adenine Nucleotide Pool

Adult rat heart myocytes prepared by collagenase perfusion show a progressive loss of adenylate energy charge and total adenine nucleotide as a function of time of anaerobic incubation in the absence of glucose. Re-aeration of the rod-shaped anaerobic cells produces a population of viable rounded cells in hypercontracture. The round cells show extensive morphological dislocations but remain metabolically competent in that they 1) restore adenosine 5'-triphosphate levels to the extent permitted by the depleted adenine nucleotide pool: 2) reestablish a low Na+-K+ ratio; and 3) restore creatine phosphate to 73% of control. The hypercontracture on re-aeration of anaerobic myocytes closely resembles an analogous contracture of heart cells in situ produced when hypoxic perfused hearts are reoxygenated, the so-called "oxygen paradox." Both processes are eliminated by inclusion of glucose during the anaerobic phase and by inhibitors of respiration and uncouplers of oxidative phosphorylation added before reoxygenation. Mitochondria in the hypercontracted myocytes retain high acceptor control ratios. Contracture on re-aeration occurs to nearly the same extent in the presence of either mM Ca2+ or 0.1 mM EGTA. Contracture appears related to dislocations in intracellular Ca metabolism that result from the declining energy charge and depleted nucleotide pool produced during anoxic incubation.

Energy status of the rapidly paced canine myocardium in congestive heart failure

1992 ◽  
Vol 73 (6) ◽  
pp. 2363-2367 ◽  
Author(s):  
C. Montgomery ◽  
N. Hamilton ◽  
C. D. Ianuzzo
Keyword(s):  
Heart Failure ◽  
Congestive Heart Failure ◽  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Energy Charge ◽  
Lactate Concentration ◽  
Energy Status ◽  
Glycogen Depletion ◽  
Myocardial Layers ◽  
Adenine Nucleotide Pool

Rapid ventricular pacing (RVP) is used as an experimental model of congestive heart failure (CHF). The purpose of this study was to determine the energy status of the dog myocardium after the development of CHF via chronic RVP. The myocardium had a significantly lower (P < 0.05) energy charge (EC) during CHF (0.63 +/- 0.01) than in sham-operated controls (0.82 +/- 0.02). This was due to significant differences in concentrations in ATP (-48%), ADP (29%), and AMP (275%) in the RVP group. However, the total adenine nucleotide pool was not different between groups. Myocardial lactate concentration was also similar. Glycogen was significantly lower (P < 0.05) by 20% at peak CHF. The adenine nucleotides were similar among the different myocardial layers (endo-, mid-, and epicardium). The administration of enalapril (an inhibitor of angiotension-converting enzyme) to decrease vascular resistance had no effect on the myocardial energy status of CHF dogs. These findings suggest that the lower EC in CHF animals is not the result of subendocardial ischemia. Also, lower EC is not associated with endogenous glycogen depletion or increased lactate concentration. The energy status of the myocardium in RVP-induced CHF is unlike that seen in ischemia-induced heart failure. This suggests that CHF in RVP is not vascular in origin.

scholarly journals Relationship Between Protein Synthesis and Secretion in Liver Cells and the State of the Adenine Nucleotide System

1979 ◽  
Vol 32 (3) ◽  
pp. 299 ◽  
Author(s):  
Kaylene Edwards ◽  
Jörg Urban ◽  
Gerhard Schreiber
Keyword(s):  
Protein Synthesis ◽  
Oxidative Phosphorylation ◽  
Protein Secretion ◽  
Liver Cell ◽  
Maximum Rate ◽  
Adenine Nucleotide ◽  
Energy Charge ◽  
Adenylate Energy Charge ◽  
Atp Level ◽  
Atp Pool

Adenine nucleotide levels could be precisely and reproducibly adjusted in liver cell suspensions by partially depleting the ATP pool with D-fructose or glycerol. Thus, it was possible to quantitatively correlate rates of protein synthesis and secretion with intracellular levels of ATP and with derived parameters, such as the adenylate energy charge. Half the maximum rate of incorporation of leucine into protein was observed at an energy charge of 0�80, a ratio of ATP to ADP of 2�6, and an ATP level of 1�05 pmol per g of wet cells. Proteins were secreted with half the maximum rate at an energy charge of 0�85, a ratio of ATP to ADP of 3�1 and an ATP concentration of 1 �1 pmol per gof wet cells. Protein secretion dill not depend on continued synthesis. Inhibitors of oxidative phosphorylation inhibited protein secretion in addition to protein synthesis, in contrast to observations by other authors on liver slices.

scholarly journals Acquired granular pool defect in stored platelets

Blood ◽  
1981 ◽  
Vol 57 (2) ◽  
pp. 203-208 ◽  
Author(s):  
AK Rao ◽  
S Niewiarowski ◽  
S Murphy
Keyword(s):  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Energy Charge ◽  
Adenylate Energy Charge ◽  
Platelet Factor ◽  
Final Volume ◽  
Before And After ◽  
Functional Defect ◽  
Metabolic Pool ◽  
The Mean

Abstract Platelets stored as concentrates (PC) for 72 h at 22 degrees C develop a functional defect. Alterations in adenine nucleotides of platelets have been shown to affect platelet function. Adenine nucleotide content of platelets was measured before and after storage and a decrease of 27.1 /+- 1.7% (mean /+- SE) in ATP and 39.1 /+- 2.6% in ADP were found in 34 PC stored with final volume of 50 ml. In 11 PC with 30 ml volume. ATP and ADP decreased by 39.4 /+- 3.2% and 49.4 /+- 2.1%, respectively. The mean ATP to ADP ratio of stored platelets was significantly higher than of fresh platelets in both groups, suggesting a relatively greater decrease in granular than metabolic pool nucleotides. Levels of low affinity platelet factor 4 measured by radioimmunoassay in plasma from 0.86 /+- 0.08 microgram/ml in the fresh PC to 8.59 /+- 0.39 microgram/ml in stored PC, indicating a concomitant alpha-granular secretion. Labeling of metabolic pool with 14C-adenine revealed a mean decrease in the adenylate energy charge of 2.0 /+- 0.4% in 12 of 16 stored PC, with a lower ATP and higher hypoxanthine labeling in stored as compared to fresh platelets. These observations suggest that stored platelets develop an acquired defect in both dense and alpha granules and in their ability to maintain ATP homeostasis.

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