Value of Adenine,Various Nucleosides,and Ouabain in Maintenance of Integrity of Red Blood Cells Under Blood Bank Conditions1

Summary. The effects of adenine and various nucleosides on adenine nucleotide metabolism in red cells, as well as on other factors related to the storability of blood were compared during six weeks of storage under blood bank conditions. Adenosine triphosphate (ATP) and total adenine nucleotides were maintained at higher levels, and higher ratios of ATP to adenine diphosphate were observed, in blood containing citrate-phosphate-dextrose (CPD) solution than in blood containing acid-citrate-dextrose (ACD) solution. Higher levels of ATP and total adenine nucleotides were maintained in blood containing ACD together with both adenine and inosine than in blood containing ACD alone or together with only one of the two purines. ACD-adenine was more effective in maintaining adenine nucleotides than was ACD-inosine. Addition of uridine did not have any effect on adenine nucleotides in red cells. ATP and total adenine nucleotides were maintained at higher levels in CPD-adenine than in CPD alone. The effect of CPD-inosine or CPD-adenine-inosine was not investigated. ACD-inosine caused a marked increase in plasma lactate, and inhibited glucose utilization, during storage. An increase in plasma inorganic phosphate was delayed by the addition of inosine, and this effect was augmented by adenine and guanosine. There were no findings suggestive of a beneficial effect of these additives on active cation transport, osmotic fragility, hemolysis, or the deterioration of blood cell morphology. Ouabain, an inhibitor of ATPase, had little effect on red cell nucleotide patterns or on other biochemical or morphological criteria for blood storage, possibly because of the low activity of ATPase at 4°C.     

Removal of Leucocytes from Whole Blood and Erythrocyte Suspensions By Filtration Through Cotton Wool

Abstract. (1) Blood was stored in polyvinyl-chloride bags containing citrate-phosphate-dextrose (CPD) with adenine in a final concentration of 0.25 mM. (2) Red cell ATP was well maintained (>70% of original) for 4 weeks in whole blood as well as in red cell concentrate (PCV 85 ± 2%). After 5 weeks the ATP level was about 70% in whole blood and about 40% in red cell concentrate. (3) Red cell 2,3-diphosphoglycerate (DPG) was about 60% of the original after 2 weeks and about 30% after 3 weeks of storage when stored both as whole blood and as red cell concentrate. (4) The red cell 24-hour post-transfusion viability was about 80% after 4 weeks of storage both as whole blood and as red cell concentrate. After 5 weeks of storage the 24-hour viability was 78.7 ± 3.5% in whole blood and 76.5 ± 6.7% in red cell concentrate. (5) 820 patients received 3,238 units of CPD-adenine blood, and 761 patients serving as controls received 2,807 units of acid-citrate-dextrose (ACD) blood. The frequency of transfusion reactions was 3.5% for patients receiving CPD-adenine blood and 4.1% for the control group. (6) The maximum storage time was set at 5 weeks for the CPD-adenine blood and 3 weeks for the ACD blood. The longer preservation time decreased out-dating by at least 50%.     

Prolonged Storage of Red Cells: The Effect of pH, Adenine and Phosphate

Prolonged storage of red blood cells (RBCs) at 4 °C results in decreased intracellular ATP levels with diminished posttransfusion survival. Meryman described a preservative medium, exceptional in its capacity to increase these intracellular levels during the first weeks of storage and later in maintaining adequate levels, for extended storage periods. We modified this medium, investigated its constituents, and found that its ATP-preserving effect was unrelated to its tonicity or to the presence of mannitol. Throughout storage, RBC potassium leakage and lactate production were moderate. No evidence of osmotic swelling was detected. In spite of high ATP levels, the cells became echinocytes, thus discounting a direct correlation between shape and metabolic status. The most striking finding in this study was that the prestorage pH of the blood unit (pH 7.0), has a crucial contribution in elevating nucleotide levels in a medium containing high levels of phosphate (18–10 m M ) and adenine. We suggest that a combined effect of optimal pH, adenine, glucose and phosphate in the medium contributes to the ability of the RBCs to synthesize the necessary purine nucleotides by the 'salvage pathway'.     

Adenine and guanine nucleotide metabolism during platelet storage at 22 degrees C

Adenine and guanine nucleotide metabolism of platelet concentrates (PCs) was studied during storage for transfusion at 22 +/- 2 degrees C over a 7-day period using high-pressure liquid chromatography. There was a steady decrease in platelet adenosine triphosphate (ATP) and adenosine diphosphate (ADP), which was balanced quantitatively by an increase in plasma hypoxanthine. As expected, ammonia accumulated along with hypoxanthine but at a far greater rate. A fall in platelet guanosine triphosphate (GTP) and guanosine diphosphate (GDP) paralleled the fall in ATP + ADP. When adenine was present in the primary anticoagulant, it was carried over into the PC and metabolized. ATP, GTP, total adenine nucleotides, and total guanine nucleotides declined more slowly in the presence of adenine than in its absence. With adenine, the increase in hypoxanthine concentration was more rapid and quantitatively balanced the decrease in adenine and platelet ATP + ADP. Plasma xanthine rose during storage but at a rate that exceeded the decline in GTP + GDP. When platelet ATP + ADP was labeled with 14C-adenine at the initiation of storage, half of the radioactivity was transferred to hypoxanthine (45%) and GTP + GDP + xanthine (5%) by the time storage was completed. The isotopic data were consistent with the presence of a radioactive (metabolic) and a nonradioactive (storage) pool of ATP + ADP at the initiation of storage with each pool contributing approximately equally to the decline in ATP + ADP during storage. The results suggested a continuing synthesis of GTP + GDP from ATP + ADP, explaining the slower rate of fall of GTP + GDP relative to the rate of rise of plasma xanthine. Throughout storage, platelets were able to incorporate 14C-hypoxanthine into both adenine and guanine nucleotides but at a rate that was only one fourth the rate of hypoxanthine accumulation. All of these data should be helpful in improving the function and viability of PC as currently stored for 5 days, in devising methods for storage beyond 5 days, and in the development of synthetic media for PC storage.     

The storage of hard-packed red blood cells in citrate-phosphate-dextrose (CPD) and CPD-adenine (CPDA-1).

The preservation of red cells "hard packed" to a hematocrit of over 80% from blood collected in citrate-phosphate-dextrose (CPD) or CPD-adenine (CPDA-1) has been investigated. After 21 days of storage, cells that had been collected in CPD solution had consumed most or all of the available glucose and manifested markedly impaired viability after reinfusion into the normal donor. In contrast, red cells prepared from blood collected in CPDA-1, a medium containing supplementary adenine and an increased amount of glucose, maintained higher glucose and adenosine triphosphate levels and, in most instances, manifested satisfactory posttransfusion viability. We emphasize that in addition to providing longer shelf life of stored blood, CPDA-1 provides a better hard-packed red cell concentrate for transfusion at 21 days.     

AMP deaminase as a cell-age marker in transient erythroblastopenia of childhood and its role in the adenylate economy of erythrocytes

Erythrocytes from 11 patients with presumptive diagnoses of transient erythroblastopenia of childhood were evaluated retrospectively (six) or prospectively (five) for a possible relationship between erythrocyte adenosine 5'-monophosphate aminohydrolase, adenylic acid deaminase (AMP deaminase) activity and intracellular concentrations of adenine nucleotides. Older red blood cell (RBC) cohorts in these patients consistently exhibited significantly decreased activities of AMP deaminase (approximately 5% to 70% of normal control mean) in association with increased concentrations (up to threefold) of adenosine triphosphate (ATP) and total adenine nucleotides. We postulate that the latter is a direct consequence of the former, since diminishing AMP deaminase activity in aging cells should reduce the drain on the adenine nucleotide pool imposed by irreversible deamination of AMP to inosine 5'-monophosphate. Consistent reductions in AMP deaminase activity indicate that this enzyme should also serve as a reliable marker of mean RBC age useful in diagnostic confirmation of transient erythroblastopenia. The observed increases in ATP and total adenine nucleotides in older RBCs require a reevaluation of the traditional view that age-related losses of these compounds mediate the ultimate demise of senescent erythrocytes. Similar alterations in the balance of degradative and salvage pathways in RBC nucleotide metabolism may also underlie certain cases of so-called "high ATP syndrome."     

Increased calcium permeability of cold-stored erythrocytes

The calcium, sodium, and magnesium permeability of erythrocytes from blood stored at 4 degrees C in various anticoagulant media has been studied and compared to that of fresh erythrocytes. Passive influx of CA2+ was measured at 37 degrees C in cells pretreated to abolish Ca2+ pumping and was up to fivefold greater for cold-stored erythrocytes than for fresh cells. The Ca2+ leakiness developed gradually after day 2 and reached a maximum by day 7 of cold storage in ACD, CPD, CPD- adenine, or heparin anticoagulants. The total calcium content of cold- stored erythrocytes in ACD was not significantly different from that of fresh erythrocytes. However, when cold-stored erythrocytes were reincubated at 37 degrees C in media containing 1.5 mM ionized calcium and substrates to regenerate ATP, a net gain of Ca2+ occurred that was greater for stored than for fresh erythrocytes. Cold storage of blood for up to 6 wk in any anticoagulant did not alter either sodium or magnesium permeability. Red cell ATP was also measured and fell steadily during cold storage in ACD or CPD, but more increase in Ca2+ permeability preceded any significant change in red cell ATP, it is likely that a selective calcium leak develops independently of the fall in ATP concentration that occurs on cold storage.     

Labeling of the releasable adenine nucleotides of washed human platelets.

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.     

Time-dependent loss of adenosine 5'-monophosphate deaminase activity may explain elevated adenosine 5'-triphosphate levels in senescent erythrocytes

Senescent erythrocytes from rabbits were previously shown to have elevated levels of adenine nucleotides. The present study documents that aged red blood cells have a normal synthetic capacity for adenine nucleotides, as indicated by normal levels of adenosine kinase. However, senescent erythrocytes do have decreased levels of adenosine 5'-monophosphate deaminase, the critical enzyme involved in degrading adenine nucleotides. These circumstances of a normal synthetic capacity in the presence of decreased catabolic ability were observed previously in a human genetic deficiency of adenosine 5'-monophosphate deaminase; the red blood cells in these patients accumulate adenosine 5'- triphosphate as do senescent erythrocytes in rabbits.     

The in vitro effect of adenine on pyruvate kinase-deficient red cells

In pyruvate kinase (PK)-deficient blood with high levels of reticulocytes, the degree of haemolysis after incubation at 37°C for 48 h was halved by the inclusion of adenine in the medium. The decrease in haemolysis was associated with a higher ATP level but was not related to the pH of the incubation mixture. The incorporation of adenine into nucleotides studied over a 3 h period was similar in normal and PK-deficient blood. The observed increase in cellular ATP was equivalent to that shown by radioactive measurements to have been synthesized from added adenine. Inhibition of mitochondrial oxidative phosphorylation in the reticulocytes of the PK-deficient blood by KCN reduced the amount of adenine taken up by the cells by a factor of 3 and altered the pattern of incorporation into the nucleotides. Only 25% of the adenine which entered the blood cells was converted into ATP compared with 85% in the absence of cyanide. Despite the synthesis of small amounts of ATP from labelled adenine, the overall ATP content fell to less than 50% of its original level. It is suggested that incubation with adenine increased the ATP level in the reticulocytes by virtue of mitochondrial oxidative phosphorylation thereby reducing the haemolysis of these cells.     

Altered intracellular purine nucleotides in gamma-irradiated red blood cell concentrates

BACKGROUND AND OBJECTIVES: Gamma irradiation at a dose of 30 Gy induces deterioration of erythrocytes, resulting in storage lesions that significantly shorten the shelf-life of packed red cell concentrates (RCCs). The aim of the present study was to investigate the effect of gamma irradiation on intracellular purine nucleotides of red blood cells during storage. MATERIALS AND METHODS: Three-day-old leucocyte-depleted saline-adenine-glucose-mannitol (SAGM)-preserved RCCs, obtained from the Blood Service of the Austrian Red Cross, were gamma irradiated with 30 Gy. Samples were taken on days 1, 2, 3 and 7 after irradiation and subsequently at weekly intervals up to the end the of shelf-life (day 39 after irradiation) and were investigated for the K+ and Na+ content in the supernatant, for intracellular concentrations of ATP, ADP, ITP, IDP, GTP and GDP of erythrocytes, and for haemolysis. RESULTS: Within the first 24 h after gamma irradiation, no metabolic or biochemical changes were detectable in the RCCs. The K+ concentration in the supernatant increased after 24 h, while the Na+ concentration decreased in irradiated units and this ion disequilibrium persisted until the end of the shelf-life. After an initial increase of intracellular ATP, ADP and GTP during the first week of storage, the intracellular concentrations of ATP, ADP, GTP and ITP decreased, while IDP increased. The decrease of ATP and ADP was found to be more pronounced in irradiated units. At the end of the shelf-life, the ATP, GTP and ITP concentrations of irradiated RCCs had decreased to < 10% of the initial level and the critical threshold of 0.8% haemolysis was reached. CONCLUSION: Gamma irradiation of SAGM-preserved RCCs leads to serious deterioration of the purine nucleotide metabolism of erythrocytes during storage, which can reduce the in vivo recovery of the transfused red cells.     

Bioluminescent assay of adenine nucleotides: rapid analysis of ATP and ADP in red cells and platelets using the LKB luminometer

Summary The assessment of both red cell and platelet function requires assay of adenine nucleotides. We describe the use of the new LKB luminometer to measure adenosine triphosphate (ATP) and adenosine diphosphate (ADP) by bioluminescence in both normal and abnormal red cells and platelets. ATP was measured a in a lysate of red cells suspended in buffer, pH 7.4, b in ethanol extracts of platelets from platelet-rich plasma (PRP) and c in ethanol extracts of supernatant platelet-poor plasma (PPP) following platelet aggregation by collagen. ADP was measured as ATP after phosphorylation by pyruvate kinase (PK) with phosphoenolpyruvate (PEP). Duplicate assays showed a variance of < 3%. Red cell lysates and ethanol extracts of PRP and PPP stored at ?40°C were stable for 4 weeks. Duplicate assays of ATP and ADP in eight samples plus standards could be performed in 2 h. Normal values were: red cells (μM/ml red cells) (n = 20), ATP 1.15 ± 0.17 (1 SD), ADP 0.22 ± 0.07, ATP/ADP (mean ratio) 5.76:1, platelets (nM/10⁹ platelets) (n = 20), ATP 53.3 ± 7.6, ADP 27.8 ± 5.8, ATP/ADP (mean ratio: 1.96:1). Abnormalities of red cell ATP and/or ADP could be demonstrated in chronic renal failure, hereditary glycolytic enzyme deficiencies and other haemolytic states. In myeloproliferative disorders defective platelet aggregation associated with storage pool deficiency and/or impaired release of ADP and ATP could be shown. We conclude that this is a reliable, rapid and economical technique for measuring red cell and platelet adenine nucleotides.     

Red Cell ATP and 2,3-Diphosphoglycerate Concentrations as a Function of Dihydroxyacetone Supplementation of CPD Adenine

Abstract. Units of CPDA-1 whole blood were subdivided and each treated with additions of dihydroxyacetone (DHA) to give final concentrations from 0 to 80m M . The 'optimum' concentration of DHA to maintain 2,3-diphosphoglycerate (2,3-DPG) with minimal loss of ATP during 42 days of storage appeared to be 30m M of DHA. With this formulation, red cell 2, 3-DPG concentrations rose to 130–140% of normal by 14 days and then decreased in a near-linear manner to 50–60% normal by 42 days, while maintaining adequate ATP levels. In addition, packed red cells were prepared from CPD fresh blood and treated with adenine, glucose, and various concentrations (0-80m M of DHA. The cells also responded most favorably to 30m M DHA, although the response was not as positive as whole blood. This concentration of DHA produced nearly 100% maintenance of 2,3-DPG at 14 days with subsequent fall to 30% of normal by 42 days.     

Preservation of Red Blood Cells: Content of Microaggregates and Di-2-Ethylhexylphthalate (DEHP) in Red Blood Cells Stored in Saline-Adenine-Glucose-Mannitol (SAGM) Medium

The content of microaggregates was determined in leukocyte-poor red blood cells (RBC) after 5 weeks of storage in citrate-phosphate-dextrose (CPD)-adenine plasma and in saline-adenine-glucose-mannitol (SAGM) medium. The size range was 3,600-200,000 fl, corresponding to a particle diameter of 19-73 micron, presuming a spherical particle shape. In comparison with CPD-adenine whole blood (100%), the total number of particles per unit of RBC was found to be 41.2% (CPD-adenine anticoagulant) and 25.4% (SAGM medium). The corresponding data for total particle volumes were 43.3 and 30.3%. The significant differences between the two categories of RBC could not be explained on the basis of differences concerning pH or cell composition. A majority of particles (50-62%) was observed in the lowest size range (19-29 microns), corresponding to only 18-26% of the total particle volume. The accumulation of di-2-ethylhexylphthalate (DEHP) was determined in two variations of RBC stored in SAGM medium and in RBC stored in CPD-adenine plasma. The quantities of DEHP per unit of RBC after 5 weeks were significantly smaller in SAGM medium (9.0 +/- 3.6 and 22.7 +/- 6.1 mg, respectively) compared to CPD-adenine plasma (30.1 +/- 9.5 mg).     

Rat liver metabolism in hemorrhagic traumatic shock

Rats were bled to a mean arterial pressure of 40 mm Hg until the onset of decompensatory shock (marked by the need to return some blood in order to maintain the blood pressure) at which time all the shed blood was returned. 31P-nuclear magnetic resonance (NMR) spectra of their livers were collected during the shock and a subsequent 60 min recovery period. Adenosine triphosphate (ATP) levels fell linearly with time, in some instances to zero during shock. ATP recovery was very rapid after return of shed blood but did not return to its preshock values. Levels of ATP remained stable during the 60 min of recovery. From the rapid recovery after total depletion of ATP in this study and in other NMR studies on perfused ischemic livers, as well as the discrepancy in residual levels of ATP during shock and ischemia as measured by in vivo NMR or by extraction techniques, we argue in favor of metabolically inaccessible pools of adenine nucleotides during these hepatic stresses.     

Storage of Human Platelets: Effects on Metabolically Active ATP and on the Release Reaction

During storage platelets rapidly lose their viability and their functions of aggregation, adhesion and secretion. This loss of function does not correlate with the small decrease in total ATP occurring. Platelet adenine nucleotides probably exist in two pools, one metabolically active and one inactive, so that only 40% of total ATP actually participates in the energy reactions. The metabolic pool was labelled by incubation of platelet-rich plasma (PRP) in acidified citric acid-sodium citrate-dextrose (ACD) with trace amounts of radioactive adenine. Platelets thus labelled in acidified ACD-PRP were stored in the same medium for 24 hr at 4°C, and the effect of storage on radioactive ATP and on the release reaction induced by collagen and thrombin was studied. The total amount of ATP decreased by only 10% during storage, whereas the metabolic ATP was reduced by 40–50% with a corresponding formation of hypoxanthine. The reactivity in the release reaction also dropped by 50%. When the acidified ACD-PRP was stored with 9 him inosine a 20% reduction of metabolic ATP and 25% reduction in release ability occurred. Storage with 8 mM adenosine also counteracted the loss in release ability, but 50% of the ATP radioactivity was lost. Adenosine increased the total ATP level during storage. Thus, the metabolic ATP pool might have been preserved intact under these circumstances, while exchange of radioactive ATP with nonradioactive ATP synthesized from adenosine took place. These results indicate strongly that during storage of platelets the metabolic ATP pool is lost by degradation to hypoxanthine in quantities that might well account for the loss in function.     

Storage of Whole Blood for up to 24 Hours at Ambient Temperature prior to Component Preparation

The effect of rapid cooling to 20-24 degrees C of whole blood immediately after collection, using 'cooling units' with butane-1,4-diol and prolonged storage up to 24 h at ambient temperature was investigated in the whole blood and the subsequently prepared plasma, buffy coat and buffy-coat-poor red cell concentrate (BC-poor RCC) in saline-adenine-glucose-mannitol (SAG M) solution. Factor VIII:C content of the plasma (n = 10), after 24 h storage was 80 +/- 3% of the initial value. In routine procedures factor VIII:C content in the plasma (n = 129 pools of 20 donor units plasma) was 0.77 +/- 0.078 IU/ml, after storage of the whole blood for 16-20 h. In whole blood (n = 10), the 2,3-diphosphoglycerate (2,3-DPG) content of the red cells decreased from 4.36 +/- 0.55 to 1.47 +/- 0.6 mumol/ml red cells after 24 h storage at 20-24 degrees C. After storage of the BC-poor RCC (n = 10) at 2-6 degrees C for 1 week, the 2,3-DPG had dropped to 0.76 +/- 0.46 mumol/ml red cells. During the first 24 h of storage of whole blood, the adenine triphosphate (ATP) levels of the red cells remained stable. A mean increase of 20% of the initial value was observed after addition of SAG M solution. In the BC-poor RCC the ATP slowly decreased to 81 +/- 5% after 5 weeks and to 68 +/- 6.6% of the initial value after 6 weeks storage.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hydrolysis of poly (A) to adenine nucleotides by purified poly (A) polymerase.

Highly purified poly(A) polymerase (polynucleotide adenylyltransferase, EC 2.7.7.19), which synthesizes poly(A) from ATP substrate, can also catalyze hydrolysis of poly(A). The enzyme, designated as poly(A) hydrolase, requires either Mn2+ or Mg2+ for activity. Although AMP is the predominant product of the reaction, ADP and ATP are also formed. The enzyme is a 3'-exonuclease that does not degrade poly(A) associated with poly(A) poly(U) helical structure. AMP, ADP, and ATP inhibit the hydrolytic reaction. These data suggest that (i) the levels of adenine nucleotides regulate synthesis and degradation of poly(A), (ii) poly(A) itself is a storage form of adenine nucleotides, (iii) the hydrolytic reaction is responsible for poly(A) shortening or turnover observed in vivo, and (iv) the synthetic and hydrolytic activities are functions of the same protein molecule.     

Evaluation of the viability and energy metabolism of canine pancreas graft subjected to significant warm ischemia damage during preservation by UW solution cold storage method

AIM: To evaluate the viability and energy metabolism of long warm ischemically damaged pancreas during preservation by the UW solution cold storage method. METHODS: The pancreas grafts subjected to 30-120 min warm ischemia were preserved by the UW solution cold storage method for 24 h. The tissue concentrations of adenine nucleotides (AN) and adenosine triphosphate (ATP) and total adenine nucleotides (TAN) were determined by using high performance liquid chromatography (HPLC) and the viability of the pancreas graft was tested in the canine model of segmental pancreas autotransplantation. RESULTS: The functional success rates of pancreas grafts of groups after 30 min, 60 min, 90 min, 120 min of warm ischemia were 100%, 100%, 67.7%, 0%, respectively. There was an excellent correlation between the posttransplant viability and tissue concentration of ATP and TAN at the end of preservation. CONCLUSION: The UW solution cold storage method was effective for functional recovery of the pancreas suffering 60-min warm ischemia. The tissue concentration of ATP and TAN at the end of 24 h preservation by the UW solution cold storage method would predict the posttransplant outcome of pancreas graft subjected to significant warm ischemia.     

Effect of acute and chronic ethanol administration on the content of coenzymes linked to energy transfer in the liver of rats fed standard or low-protein diet.

1) In rats fed a standard diet or a protein restricted diet the effect of acute and chronic ethanol administration on liver content of adenine nucleotides was studied. In the long-term experiments the total liver content of NAD and NADP was additionally determined. 2) a single oral ethanol load does not significantly influence the total adenine nucleotide content. Liver AMP content increases immediately following ethanol ingestion about 2-fold and remains elevated for 12 hours. ATP content and ATP/ADP ratio are significantly reduced within 30 minutes after ethanol administration. Both return to initial values after 2 hours adn decrease again thereafter. 3) The increase in the AMP content is dose dependent, i.e. it is more pronounced after small doses of ethanol and is not observed when blood ethanol concentrations are very high. The elevation of the AMP levels during ethanol oxidation is interpreted as a consequence of increased ATP consumption and of inhibition of citric acid cycle. 4) In animals fed nearly protein-free diet, total adenine nucleotide content and ATP content are distinctly reduced. An increase in AMP concentration is not observed in these rats where ethanol oxidation is markedly inhibited. 5) Chronic ethanol application does neither in rats kept on a standard diet nor in those fed a protein restricted regimen affect the liver content of total adenine nucleotides or ATP. Similarly the total content of NAD and NADP shows no major changes. 6) It is concluded that the relatively small alterations in total liver adenine nucleotide content and in the different adenine nucleotide fractions are not important for ethanol-induced fat accumulation or other disturbances in the liver.