Comparison in control and severely diabetic, alloxanized rats of phosphate fractions, glycogen and fat

1959 ◽  
Vol 196 (6) ◽  
pp. 1246-1249 ◽  
Author(s):  
Clarissa H. Beatty ◽  
Ruth D. Peterson ◽  
Rose Mary Bocek ◽  
Edward S. West
Keyword(s):  
Body Weight ◽  
Inorganic Phosphate ◽  
Trichloroacetic Acid ◽  
Adenosine Diphosphate ◽  
Creatine Phosphate ◽  
Soluble Phosphate ◽  
Total Acid ◽  
Control Series ◽  
Noncollagenous Protein ◽  
Total Muscle

Homogeneous aliquots of powdered muscle were analyzed and levels of constituents calculated on a fat-free basis. When compared to muscle from control rats, muscle from severely diabetic, alloxanized rats showed a decrease in creatine phosphate, total acid soluble phosphate and total phosphate, with no change in inorganic phosphate, adenosine diphosphate plus adenosine triphosphate, or total acid soluble phosphate minus 7-minute hydrolyzable phosphate, creatine, noncollagenous protein or total nitrogen. There was an increase in the trichloroacetic acid extractable glycogen value in the muscle of the alloxan diabetic as compared to the control series. The concentration of fat in the muscle itself was higher in the diabetic than in the control series, although the total muscle fat had decreased in the diabetic series due to the decrease in percentage of body weight represented by muscle.

scholarly journals Post-mortem glycolysis in ox skeletal muscle. Effect of temperature on the concentrations of glycolytic intermediates and cofactors

1967 ◽  
Vol 105 (1) ◽  
pp. 127-136 ◽  
Author(s):  
R. P. Newbold ◽  
R. K. Scopes
Keyword(s):  
Skeletal Muscle ◽  
Creatine Phosphate ◽  
Effect Of Temperature ◽  
Soluble Phosphate ◽  
Hexose Monophosphate ◽  
Post Mortem ◽  
Total Acid ◽  
Atp Turnover ◽  
Glycolytic Intermediates ◽  
Phosphofructokinase Activity

1. Post-mortem changes in the concentrations of the following compounds in ox sternomandibularis muscles stored in nitrogen at 1°, 5° and 15° are reported: Pi creatine phosphate, hexose monophosphates, fructose diphosphate, triose phosphates, α-glycerophosphate, phosphoglycerates, lactate, ATP, ADP, AMP, NAD+ and total nucleotides. Some results obtained with muscles stored at 37° are included. 2. At the time the muscles were placed at controlled temperatures (about 1·5hr. post mortem) the phosphorus in the compounds measured accounted for 91±6% (s.d.) of the total acid-soluble phosphate. 3. The results indicated that at all temperatures the activities of the phosphorylase and phosphofructokinase steps limited the rate and the extent of post-mortem glycolysis. 4. The large variations in hexose monophosphate concentrations during storage indicated that the ratio of phosphorylase to phosphofructokinase activity varied considerably with time and temperature. 5. Between 3·5 and 7hr. post mortem the rates of glycolysis and of ATP turnover were not slower at 5° that at 15°, and were probably faster at 1°. The significance of this finding is discussed.

Phosphate uptake by isolated rabbit heart

1962 ◽  
Vol 202 (6) ◽  
pp. 1147-1151 ◽  
Author(s):  
Akira Omachi ◽  
John M. Ginski ◽  
Robert I. Macey
Keyword(s):  
Inorganic Phosphate ◽  
Time Course ◽  
Phosphate Uptake ◽  
Specific Activity ◽  
Rabbit Heart ◽  
High Energy ◽  
Soluble Phosphate ◽  
Total Acid ◽  
Uptake Mechanism ◽  
Tissue Fraction

Isolated rabbit hearts were perfused with Locke Ringer's fluid to which P32 was added. Cellular uptake of P32 was determined by analyzing ventricles from which a rapidly exchangeable extracellular P32 fraction had been removed. In studies on concentration dependence, a plot of phosphate uptake during 1 hr of perfusion against perfusate phosphate concentration revealed that the early phase of uptake follows saturation kinetics. In studies on time course with high external phosphate, i.e., at a level where the uptake mechanism is apparently saturated, relative specific activity (RSA) of total acid-soluble phosphate attained a plateau in 2 hr. RSA is the ratio of specific activities of a tissue fraction to perfusate inorganic phosphate (IP). The plateau was reached at a level corresponding to 10% of the equilibrium value, and it appears that early uptake of phosphate may be confined to a single, rapidly exchanging compartment. This pool appears to contain high-energy and inorganic phosphate since 90% of tissue P32 was found in adenosine polyphosphate, phosphocreatine, and IP fractions. Perfusion with low phosphate led to a decrease in tissue IP with relatively little variation in organic phosphates. This depletion of IP seemed to be accompanied by the emergence of a second compartment as revealed by the RSA data.

Is Phospholipase A2 (PLA2) Involved In PAF-Acether Formation By Platelets

1981 ◽  
Author(s):  
M Chignard ◽  
B B Vargaftig ◽  
J P Le Couedic ◽  
J Benveniste
Keyword(s):  
Arachidonic Acid ◽  
Cyclic Amp ◽  
Chelating Agents ◽  
Creatine Phosphokinase ◽  
Platelet Activating Factor ◽  
Calcium Ionophore ◽  
Adenosine Diphosphate ◽  
Creatine Phosphate ◽  
Dibutyryl Cyclic Amp ◽  
A 23187

PAF-acether (platelet-activating factor) has been recently identified as l-O-alkyl-2-acetyl-sn-glyceryl-phosphorylcholine, and later chemically synthetized. Platelets form PAF-acether upon stimulation with the calcium ionophore A 23187 or with more physiological stimuli such as thrombin or collagen. By contrast, arachidonic acid (AA) and adenosine diphosphate (ADP) do not trigger formation of PAF-acether. Since 1) PAF-acether is a phospholipid derivative and 2) aggregating agents which trigger PAF-acether formation are potent platelet PLA2 stimulators, we speculated that PLA2 could be implicated in its formation.Rabbit washed platelets were incubated at 37°C in the presence of thrombin (2.5 U/ml) or of ionophore A 23187 (2.5 uM) for 7 min and ethanol (80 % final) was added. After centrifugation, the supernatant was evaporated and concentrated. The extract was tested for its aggregating property on rabbit washed platelets preincubated with a cyclo-oxygenase inhibitor (aspirin) and an ADP scavenging system (creatine phosphate and creatine phosphokinase).In the presence of calcium chelating agents such as EDTA (5 mM) and EGTA (5 mM) most of the synthesis of PAF-acether was suppressed (93 % and 100 % of inhibition respectively). Dibutyryl cyclic AMP (5 mM) also suppressed PAF-acether formation from platelets challenged by thrombin or by the ionophore A 23187 (100 % and 62 % inhibition respectively). Bromophenacyl bromide (0.1 mM) and compound CB 874 (0.1 mM) proved also to be very potent inhibitors of PAF-acether synthesis (100 % inhibition both). All these drugs are well-known platelet PLA2 inhibitors. Upon stimulation platelets also form a deacetylated PAF-acether (lyso- PAF-acether) which could be the direct precursor of PAF-acether. The release of lyso-PAF-acether and the blockade of PAF-acether formation by various molecules having in common a PLA- inhibitory activity lead us to conclude that a PLA2 may be implicated in PAF-acether formation from platelets. Alternative explanations include the possibility that the various inhibitors act on other membrane-related sites.

scholarly journals Participation of ADP in the binding of fibrinogen to thrombin- stimulated platelets

Blood ◽  
1980 ◽  
Vol 56 (3) ◽  
pp. 553-555 ◽  
Author(s):  
EF Plow ◽  
GA Marguerie
Keyword(s):  
Creatine Phosphokinase ◽  
Adenosine Diphosphate ◽  
Creatine Phosphate ◽  
Human Platelets ◽  
Serotonin Release ◽  
Fibrinogen Binding ◽  
Platelet Secretion

Abstract Thrombin and adenosine diphosphate (ADP) supported the binding of 125I- fibrinogen to washed human platelets with similar kinetics and affinity. Platelet secretion, as measured by 14C-serotonin release, and fibrinogen binding exhibited an identical dependence on thrombin concentration. Enzymatic removal of ADP with apyrase or creatine phosphate/creatine phosphokinase (CP/CPK) from thrombin-stimulated platelets markedly inhibited 125I-fibrinogen binding, but pretreatment of platelets with CP/CPK prior to thrombin stimulation was without effect. Thus, ADP, released from the platelet, participates in the binding of fibrinogen to thrombin-stimulated platelets.

Iodoacetate-induced skeletal muscle contracture: changes in ADP, calcium, phosphate, and pH

1995 ◽  
Vol 268 (2) ◽  
pp. C317-C322 ◽  
Author(s):  
R. L. Ruff ◽  
J. Weissman
Keyword(s):  
Fold Increase ◽  
Creatine Phosphate ◽  
Iodoacetic Acid ◽  
Intracellular Acidification ◽  
Muscle Water Content ◽  
Muscle Water ◽  
Creatine Kinase Reaction ◽  
Cr Creatine ◽  
Total Muscle ◽  
Stimulation Of

The effects of iodoacetic acid (IAA) and ischemic contraction were studied in rat extensor digitorum longus muscles. Ischemic stimulation of IAA-treated muscles produced contracture. We measured total muscle water content, distribution of water between intracellular and extracellular spaces, creatine concentration ([Cr]), creatine phosphate concentration ([PCr]), [ATP], [Pi], intracellular pH, and intracellular Ca2+ concentration ([Ca2+]i) at the onset of contracture. [ADP] was calculated from the equilibrium of the creatine kinase reaction using the measured values of [ATP], [PCr], [Cr], and pH. At the onset of contracture there was a 75% reduction of [PCr], a 12-fold increase in [ADP], and an 11-fold increase in [Ca2+]i compared with unstimulated IAA-treated muscles. [ATP] was not depleted at contracture compared with unstimulated IAA-treated muscles, and [Pi] increased less in muscles at contracture compared with stimulated control muscles. The persistent tension in contractures probably resulted from increased [Ca2+]i combined with increased myofibrillar Ca2+ sensitivity due to elevated [ADP] and relatively reduced intracellular acidification and [Pi].

scholarly journals Zinc-induced platelet aggregation is mediated by the fibrinogen receptor and is not accompanied by release or by thromboxane synthesis

Blood ◽  
1985 ◽  
Vol 66 (1) ◽  
pp. 213-219 ◽  
Author(s):  
P Heyns A du ◽  
A Eldor ◽  
R Yarom ◽  
G Marx
Keyword(s):  
Platelet Aggregation ◽  
Dense Body ◽  
Platelet Rich Plasma ◽  
Adenosine Monophosphate ◽  
Adenosine Diphosphate ◽  
Creatine Phosphate ◽  
Calcium Flux ◽  
Fibrinogen Receptor ◽  
Induced Aggregation

Abstract We demonstrate that zinc (0.1 to 0.3 mmol/L) induces aggregation of washed platelet suspensions. Higher concentrations (1 to 3 mmol/L) of zinc were needed to aggregate platelets in platelet-rich plasma obtained from blood anticoagulated with low-molecular-weight heparin, probably due to the binding of zinc to the plasma proteins. Zinc- induced aggregation of normal washed platelets required added fibrinogen and no aggregation occurred with thrombasthenic platelets or with normal platelets pretreated with a monoclonal antibody (10E5) that blocks the platelet fibrinogen receptor. These data indicate that the platelet membrane fibrinogen receptor-glycoproteins IIb and IIIa mediate the effect of zinc. Zinc-induced aggregation was blocked by the agent TMB-8, which interferes with the internal calcium flux, and by prostacyclin, which elevates platelet cyclic adenosine monophosphate levels. Zinc-induced aggregation was not accompanied by thromboxane synthesis or by the secretion of dense-body serotonin and was not affected by preexposure of platelets to acetylsalicylic acid. Experiments with creatine phosphate/creatine phosphokinase showed that the zinc effect on platelets was independent of extracellular adenosine diphosphate (ADP). Zinc had an additive effect when platelet aggregation was stimulated with subthreshhold concentrations of collagen or ADP. Together with the known effects of nutritional zinc on in vivo bleeding, on platelet aggregation, and on lipid metabolism, the results suggest that zinc may have an important bearing on normal hemostasis, thrombosis, and atherosclerosis.

Myocardial adenine pool depletion and recovery of mechanical function following ischemia

1985 ◽  
Vol 248 (5) ◽  
pp. H644-H651
Author(s):  
S. M. Humphrey ◽  
D. G. Holliss ◽  
R. N. Seelye
Keyword(s):  
Inorganic Phosphate ◽  
Time Course ◽  
Creatine Phosphate ◽  
Limiting Factor ◽  
Ischemia And Reperfusion ◽  
Mechanical Function ◽  
Rat Hearts ◽  
Complete Failure ◽  
Hemodynamic Function ◽  
Mechanical Recovery

The loss of nucleotide pool precursors from the heart during ischemia and reperfusion may affect resynthesis of ATP and consequently mechanical recovery. Isolated working rat hearts were made globally ischemic for from 15 to 25 min, and the tissue content of adenine pool metabolites, creatine, creatine phosphate (CP), and inorganic phosphate (Pi), were measured after 20 min of reperfusion. In addition, the coronary effluent was assayed for nucleotides, nucleosides, and oxypurines. Hearts that recovered 75% or more of their preischemic hemodynamic function had significantly lower ATP and NAD but greater CP and Pi than controls. Complete failure of hearts was associated with severely depleted ATP but not CP. All hearts released 25% or more of their preischemic adenine pool during the 20-min reperfusion. This loss correlated more closely with a reduction in recovery from 100 to 75% than with complete failure. Thus extensive loss of adenine pool precursors is not critically related to the failure of heart muscle to recover function but may be an important limiting factor in determining the extent and time course of mechanical recovery.

scholarly journals FURTHER STUDIES ON EFFECTS OF TISSUE EXTRACTS ON STAPHYLOCOCCUS AUREUS

1946 ◽  
Vol 84 (3) ◽  
pp. 247-261 ◽  
Author(s):  
Leo G. Nutini ◽  
Sister Eva Maria Lynch
Keyword(s):  
Staphylococcus Aureus ◽  
Body Weight ◽  
The Body ◽  
Brain Extract ◽  
Toxicity Tests ◽  
Control Series ◽  
Experimental Animals ◽  
Tissue Extracts

1. The ability of alcoholic-precipitated extracts of beef tissue—brain, spleen, heart, and kidney—to stimulate the growth of Staphylococcus aureus, in vitro, and to convert the yellow S form to a white R variant with altered biochemical characteristics conforming to those of an avirulent organism, has been confirmed. 2. The avirulence of the white R variant has been established by tests in vivo on mice. 3. Staphylococcus aureus infections induced subcutaneously, intraperitoneally, and intravenously in mice responded favorably to brain extract following subcutaneous or oral administration. The mortality was 2 per cent in 444 experimental animals and 81 per cent in 448 control animals. 4. The extracts appeared equally efficient when used therapeutically (mortality 2 per cent of 162 experimental animals and 90 per cent in the control series) or prophylactically (mortality 2 per cent of 282 experimental animals and 76 per cent in 286 control mice). Extracts of brain and spleen were more effective than those of either heart or kidney. 5. Studies concerning the mechanism of action of the tissue extracts indicate that they prevented the formation of toxin by Staphylococcus aureus, and had but little effect on toxin actions. 6. Toxicity tests revealed that the brain and spleen extracts were relatively non-toxic, dosages equivalent to 2 per cent of the body weight being well tolerated. Kidney and heart extracts were much more toxic, producing mortality in dosages as low as 0.3 per cent of the body weight.

scholarly journals The increase of oxygen consumption after a flash of light is tightly coupled to sodium pumping in the lateral ocellus of barnacle.

1990 ◽  
Vol 96 (1) ◽  
pp. 83-108 ◽  
Author(s):  
H Widmer ◽  
S Poitry ◽  
M Tsacopoulos
Keyword(s):  
Oxygen Consumption ◽  
Inorganic Phosphate ◽  
Photoreceptor Cells ◽  
Adenosine Diphosphate ◽  
Bathing Solution ◽  
Intracellular Injection ◽  
Metabolic Products ◽  
Lateral Ocellus ◽  
Tightly Coupled ◽  
Intense Light

In the lateral ocellus of the barnacle, we have tested the hypothesis that the transient increase of oxygen consumption (delta QO2) induced by light results from an increase in the rate of Na+ pumping. With a Na(+)-sensitive microelectrode, we measured the intracellular concentration of Na+ (Nai) in the photoreceptor cells. Nai was 17.6 +/- 1.2 mM (SE; n = 18) in darkness and it increased transiently by 10-20 mM after an 80-ms flash of intense light. The increase of Nai recovered in about the same time as the delta QO2, and the Na+/O2 ratio was 19.2 +/- 3.8 (SE; n = 6). Removing Na+ from the bath caused the delta QO2 to decrease by 79 +/- 3% (SE; n = 5). Exposure to 25 microM ouabain inhibited Na+ pumping and abolished the delta QO2. Removal of K+ from the bathing solution inhibited Na+ pumping in darkness, but mostly shortened the duration of the delta QO2; with a K(+)-sensitive microelectrode, we measured pericellular [K+] and found that it increased after the flash for about the same time as the delta QO2. Increasing Na+ pumping in darkness by reintroducing K+ in the bath or by injecting Na+ into one of the photoreceptor cells induced a delta QO2. Finally, intracellular injection of adenosine diphosphate and inorganic phosphate (ADP + Pi), the metabolic products of ATP splitting by the Na+ pump, also induced a delta QO2 in darkness. We conclude that all the results obtained are consistent with the formulated hypothesis.

Sign in / Sign up

Export Citation Format

Share Document