scholarly journals Energy Requirement for Maintenance of Adenylate Energy Charge and Metabolic ATP in Platelets During Starvation

1977 ◽  
Author(s):  
J.W.N. Akkerman ◽  
G. Gorter ◽  
J.J. Sixma
Keyword(s):  
Steady State ◽  
Adenine Nucleotides ◽  
Energy Requirement ◽  
Energy Charge ◽  
Lactate Production ◽  
Stable Steady State ◽  
Adenylate Energy Charge ◽  
Consumption Energy ◽  
Steady State Levels ◽  
Lactate Formation

Energy requirements for maintenance of stable adenylate energy charge (AEC) and metabolic ATP(ATP-m)level were studied in gel filtered platelets at various degrees of starvation. Platelets gel filtered and subsequently incubated during 40 min.at 37°C with 1mM CN- and without glucose consumed their glycogen at a rate of 0.79 ± 0.23(± SD, n=6)/μmol glycosyl residues .min-1 10-11 cells. During this period AEC and ATP-m decreased linearly with time at rates of 5-6.10-3 and 0.75-1.05% of total radioactive adenine nucleotides .min-1.10-11 cells respectively. Addition of 25–1000μM glucose increased lactate production and decreased the fall of AEC and ATP-m proportional to the amounts of glucose added. Glycogenolysis remained active below 100μM glucose but ceased at higher glucose concentrations. From these data ATP-m production from glycogenolysis and glycolysis was calculated and compared with the decrease of steady state levels of AEC and ATP-m. A production of 3μmol ATP-m.min-1.10-11 cells was required to maintain initial AEC and ATP-m level. At lower rates of ATP-m production these values fell without reaching stable steady state levels in a lower range. After 40-50 min variations in AEC and ATP-m ceased and lactate formation stopped leaving the cells in a state of hybernation. Subsequent addition of glucoserestored lactate accumulation, AEC and ATP-m. On the basis of formation and steady state levels of ATP-m its consumption was calculated. A lowering production was not completely met by a lowering consumption. Energy consumption in resting platelets is therefore partly independent from energy production.

scholarly journals Platelet functions and energy metabolism in a patient with hexokinase deficiency

Blood ◽  
1984 ◽  
Vol 63 (1) ◽  
pp. 147-153 ◽  
Author(s):  
JW Akkerman ◽  
G Rijksen ◽  
G Gorter ◽  
GE Staal
Keyword(s):  
Adenine Nucleotides ◽  
Energy Charge ◽  
Energy Generation ◽  
Adenosine Diphosphate ◽  
Dense Granule ◽  
Glycolytic Flux ◽  
Adenylate Energy Charge ◽  
Severe Reduction ◽  
Dense Granule Secretion ◽  
Granule Secretion

Abstract We have studied the regeneration of adenosine triphosphate (ATP) in the glycolytic pathway in platelets with a 75% reduction in hexokinase (HK) activity and have investigated aggregation and Ca2+ secretion. HK- deficient platelets had a normal glycolytic flux in the resting state, but responded insufficiently to stimulation with thrombin (5 U/ml). In contrast, glycogen contents and glycogenolysis were normal. When the metabolic adenine nucleotides were labeled with 14C-adenine, the patient's platelets showed a normal adenylate energy charge and a normal level of 14C-ATP. However, the inhibitor of mitochondrial energy generation, CN-, induced a weaker fall in 14C-ATP in the patient's platelets than in the controls. Analysis of secretion markers revealed decreased amounts of granule-bound ATP and secretable Ca2+, whereas granule-bound adenosine diphosphate (ADP), beta-thromboglobulin, N- acetyl-beta-D-glucosaminidase, and beta-glucuronidase were within the normal range. Aggregation and Ca2+ secretion induced by 5 U/ml thrombin were normal and were not changed in the presence of inhibitors of mitochondrial and glycogenolytic energy generation. Aggregation was also normal at 0.1 U/ml thrombin and was independent of these inhibitors, but Ca2+ secretion was greatly impaired when mitochondrial and glycogenolytic ATP resynthesis was abolished. These findings indicate that a severe reduction in HK activity causes insufficient acceleration of the glycolytic flux during stimulation with thrombin. This leads to impaired dense granule secretion in conditions where secretion depends on concurrent ATP resynthesis and glycolysis is rate limiting.

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.

Changes of platelets’ function in preeclampsia

Open Medicine ◽  
2011 ◽  
Vol 6 (6) ◽  
pp. 696-700
Author(s):  
Goran Babic ◽  
Slobodan Novokmet ◽  
Slobodan Jankovic
Keyword(s):  
Platelet Aggregation ◽  
Adenine Nucleotides ◽  
Energy Charge ◽  
Adenosine Diphosphate ◽  
Control Group ◽  
Adenylate Energy Charge ◽  
Cross Sectional ◽  
Blood Samples ◽  
Metabolic Pool ◽  
Aggregation Of Platelets

AbstractIncreased aggregation of platelets during preeclampsia was shown in several studies, yet several others reported no change. The aim of our study was to investigate platelet aggregation in a group of patients suffering from preeclampsia. In a cross-sectional study blood samples were taken from 89 hospitalized patients in the third trimester of pregnancy: 38 were suffering from mild to moderate preeclampsia and 51 patients were without preeclampsia. From the blood samples platelet aggregation, secretion of adenine nucleotides from platelets, concentration of energy-rich adenine compounds and levels of cyclic adenosine-mono-phosphate and cyclic guanosine mono-phosphate in platelets were measured. In the patients with preeclampsia, the adenosine diphosphate threshold for biphasic aggregation [odds ratio (OR):.75; 95% Confidence Interval (CI): 0.55–1.02; p<0.05], total adenine nucleotides concentration in the metabolic pool of platelets (OR:0.99; CI: 0.62–1.57; p<0.01) and cyclic adenosine-mono-phosphate (OR:0.81; CI: 0.57, 1.14; p<0.05) and cyclic guanosine mono-phosphate (OR:.78; CI: 0.55–1.09; p<0.05) levels in platelets were decreased in comparison with the control group, while adenylate energy charge in the metabolic pool of platelets (OR: >100.00; CI: 0.00->100.00; p<0.05) and secretion of adenosine triphosphate (OR:.13; CI: 0.00–14.26; p<0.05) and adenosine diphosphate (OR:.77; CI: 0.08–36.79; p<0.05) were increased. The results of our study show increased activation and aggregation of platelets in pregnant females with preeclampsia.

Liquid chromatography of serotonin and adenine nucleotides in blood platelets, illustrated by evaluation of functional integrity of platelet preparations.

1985 ◽  
Vol 31 (5) ◽  
pp. 695-698 ◽  
Author(s):  
O C Ingebretsen ◽  
A M Bakken ◽  
M Farstad
Keyword(s):  
Adenine Nucleotides ◽  
Blood Platelets ◽  
Energy Charge ◽  
Adenylate Energy Charge ◽  
Experimental Procedure ◽  
Release Reaction ◽  
Functional Integrity ◽  
Chromatographic Procedure ◽  
Platelet Release ◽  
Liquid Chromatographic

Abstract In this relatively rapid liquid-chromatographic procedure the endogenous serotonin in blood platelets is quantified by fluorometry. We used this experimental procedure to estimate the platelet-release reaction as an indicator of the functional integrity of stored platelets. a decrease in the platelet-release reaction more sensitively indicates platelet changes during storage than do alterations in total ATP concentration or adenylate energy charge. The described method for quantifying serotonin is convenient enough for routine use in blood banks.

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.

scholarly journals Platelet functions and energy metabolism in a patient with hexokinase deficiency

Blood ◽  
1984 ◽  
Vol 63 (1) ◽  
pp. 147-153
Author(s):  
JW Akkerman ◽  
G Rijksen ◽  
G Gorter ◽  
GE Staal
Keyword(s):  
Adenine Nucleotides ◽  
Energy Charge ◽  
Energy Generation ◽  
Adenosine Diphosphate ◽  
Dense Granule ◽  
Glycolytic Flux ◽  
Adenylate Energy Charge ◽  
Severe Reduction ◽  
Dense Granule Secretion ◽  
Granule Secretion

We have studied the regeneration of adenosine triphosphate (ATP) in the glycolytic pathway in platelets with a 75% reduction in hexokinase (HK) activity and have investigated aggregation and Ca2+ secretion. HK- deficient platelets had a normal glycolytic flux in the resting state, but responded insufficiently to stimulation with thrombin (5 U/ml). In contrast, glycogen contents and glycogenolysis were normal. When the metabolic adenine nucleotides were labeled with 14C-adenine, the patient's platelets showed a normal adenylate energy charge and a normal level of 14C-ATP. However, the inhibitor of mitochondrial energy generation, CN-, induced a weaker fall in 14C-ATP in the patient's platelets than in the controls. Analysis of secretion markers revealed decreased amounts of granule-bound ATP and secretable Ca2+, whereas granule-bound adenosine diphosphate (ADP), beta-thromboglobulin, N- acetyl-beta-D-glucosaminidase, and beta-glucuronidase were within the normal range. Aggregation and Ca2+ secretion induced by 5 U/ml thrombin were normal and were not changed in the presence of inhibitors of mitochondrial and glycogenolytic energy generation. Aggregation was also normal at 0.1 U/ml thrombin and was independent of these inhibitors, but Ca2+ secretion was greatly impaired when mitochondrial and glycogenolytic ATP resynthesis was abolished. These findings indicate that a severe reduction in HK activity causes insufficient acceleration of the glycolytic flux during stimulation with thrombin. This leads to impaired dense granule secretion in conditions where secretion depends on concurrent ATP resynthesis and glycolysis is rate limiting.

scholarly journals The energetics of early platelet responses. Energy consumption during shape change and aggregation with special reference to protein phosphorylation and the polyphosphoinositide cycle

1985 ◽  
Vol 228 (2) ◽  
pp. 451-462 ◽  
Author(s):  
A J M Verhoeven ◽  
G Gorter ◽  
M E Mommersteeg ◽  
J W Akkerman
Keyword(s):  
Steady State ◽  
Energy Consumption ◽  
Phosphatidic Acid ◽  
Protein Phosphorylation ◽  
Shape Change ◽  
Energy Requirement ◽  
Metabolic Energy ◽  
Stimulus Response ◽  
Early Increase ◽  
Steady State Levels

Among the different platelet responses, secretion requires the greatest amount of metabolic energy. The velocities of dense, alpha- and acid hydrolase granule secretion vary in parallel with the increase in energy consumption seen in thrombin-stimulated cells. This covariance is preceded by a phase in which energy consumption is increased without the extracellular appearance of secretion markers. By treating the platelets with thrombin and hirudin we have stimulated the platelets for short intervals and succeeded in separating shape change, single platelet disappearance and secretion to a great extent. In this report we show that the early increase in energy consumption reflects the energy requirement of aggregation but not of shape change. The cost of 100% of single platelet disappearance is 2.8 mumol of ATPeq. X (10(11) platelets)-1. Concurrent analysis of phosphorylation of Mr 20 000 and 47 000 proteins and of 32P-labelled phosphatidylinositol metabolites led to the following observations. Firstly, shape change is neither accompanied by an increase in protein phosphorylation nor by changes in the steady state levels of 32P-labelled phosphatidylinositol metabolites. Secondly, when aggregation occurs both proteins are phosphorylated, but the phosphatidylinositol metabolites do not change. Thirdly, when secretion follows, more phosphorylation of the Mr 47 000 protein occurs and initially only phosphatidic acid accumulates. At a later stage of the secretion responses, more protein phosphorylation and phosphatidic acid accumulation become evident, and are now accompanied by alterations in the steady state levels of 32P-labelled (poly)phosphoinositides. Hence, the early increase in energy consumption coincides with protein phosphorylation and, at a later stage, with alterations in (poly)phosphoinositides metabolites. This demonstrates that metabolic energy is directly involved in stimulus-response coupling in aggregating platelets.

Adenylate kinase 1 deficiency disrupts mouse sperm motility under conditions of energy stress†

2020 ◽  
Vol 103 (5) ◽  
pp. 1121-1131
Author(s):  
Minyu Xie ◽  
Guofei Zhang ◽  
Hanbin Zhang ◽  
Feilong Chen ◽  
Yan Chen ◽  
...  
Keyword(s):  
Sperm Motility ◽  
Adenylate Kinase ◽  
Adenine Nucleotides ◽  
Critical Role ◽  
Energy Charge ◽  
Energy Restriction ◽  
Adenylate Energy Charge ◽  
Testis Development ◽  
Physiological Conditions ◽  
Energy Stress

Abstract Mammalian spermatozoa are highly polarized cells characterized by compartmentalized cellular structures and energy metabolism. Adenylate kinase (AK), which interconverts two ADP molecules into stoichiometric amounts of ATP and AMP, plays a critical role in buffering adenine nucleotides throughout the tail to support flagellar motility. Yet the role of the major AK isoform, AK1, is still not well characterized. Here, by using a proteomic analysis of testis biopsy samples, we found that AK1 levels were significantly decreased in nonobstructive azoospermia patients. This result was further verified by immunohistochemical staining of AK1 on a tissue microarray. AK1 was found to be expressed in post-meiotic round and elongated spermatids in mouse testis and subsequent mature sperm in the epididymis. We then generated Ak1 knockout mice, which showed that AK1 deficiency did not induce any defects in testis development, spermatogenesis, or sperm morphology and motility under physiological conditions. We further investigated detergent-modeled epididymal sperm and included individual or mixed adenine nucleotides to mimic energy stress. When only ADP was available, Ak1 disruption largely compromised sperm motility, manifested as a smaller beating amplitude and higher beating frequency, which resulted in less effective forward swimming. The energy restriction/recover experiments with intact sperm further addressed this finding. Besides, decreased AK activity was observed in sperm of a male fertility disorder mouse model induced by cadmium chloride. These results cumulatively demonstrate that AK1 was dispensable for testis development, spermatogenesis, or sperm motility under physiological conditions, but was required for sperm to maintain a constant adenylate energy charge to support sperm motility under conditions of energy stress.

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