Phosphate Uptake into Organic Compounds in Skeletal Muscle

1975 ◽  
Vol 53 (2) ◽  
pp. 317-321
Author(s):  
C. R. Dunkley ◽  
J. F. Manery
Keyword(s):  
Skeletal Muscle ◽  
Organic Compounds ◽  
Adenosine Triphosphate ◽  
Inorganic Phosphate ◽  
Phosphate Uptake ◽  
Organic Phosphate ◽  
Glycerol Phosphate ◽  
Water Extracts ◽  
Ringer’S Solution ◽  
Phosphate Compounds

Isolated intact frog muscles were incubated in 32P-labelled Ringer's solution for various periods of time (30 s – 20 h). Labelled compounds were isolated from TCA, methanol–chloroform–water, and water extracts of muscle. Hexosephosphates, phosphocreatine, phosphoenolphyruvate, α-glycerol phosphate, adenosine triphosphate, and inorganic phosphate were identified after 30 s, and 4 h incubation. Much more labelling was found after 20 h. The incorporation of 32P in 30 s into organic phosphate compounds, such as α-glycerol phosphate and ATP, showed that immediate esterification of Pi occurred on, or just inside, the sarcolemma.

Phosphate uptake in rat skeletal muscle is reduced during isometric contractions

2004 ◽  
Vol 97 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Kirk A. Abraham ◽  
Ronald L. Terjung
Keyword(s):  
Skeletal Muscle ◽  
Inorganic Phosphate ◽  
Phosphate Uptake ◽  
Specific Activity ◽  
Fiber Type ◽  
Rat Skeletal Muscle ◽  
Energy Expenditures ◽  
Contraction Duration ◽  
Uptake Rates ◽  
White Gastrocnemius

During contractions, there is a net efflux of phosphate from skeletal muscle, likely because of an elevated intracellular inorganic phosphate (Pi) concentration. Over time, contracting muscle could incur a substantial phosphate deficit unless Pi uptake rates were increased during contractions. We used the perfused rat hindquarter preparation to assess [32P]Pi uptake rates in muscles at rest or over a range of energy expenditures during contractions at 0.5, 3, or 5 Hz for 30 min. Pi uptake rates were reduced during contractions in a pattern that was dependent on contraction frequency and fiber type. In soleus and red gastrocnemius, [32P]Pi uptake rates declined by ∼25% at 0.5 Hz and 50–60% at 3 and 5 Hz. Uptake rates in white gastrocnemius decreased by 65–75% at all three stimulation frequencies. These reductions in Pi uptake are not likely confounded by changes in precursor [32P]Pi specific activity in the interstitium. In soleus and red gastrocnemius, declines in Pi uptake rates were related to energy expenditure over the contraction duration. These data imply that Pi uptake in skeletal muscle is acutely modulated during contractions and that decreases in Pi uptake rates, in combination with expected increases in Pi efflux, exacerbate the net loss of phosphate from the cell. Enhanced uptake of Pi must subsequently occur because skeletal muscle typically maintains a relatively constant total phosphate pool.

High Energy Phosphates During Hibernation and Arousal in the Ground Squirrel

1958 ◽  
Vol 195 (1) ◽  
pp. 233-236 ◽  
Author(s):  
Marilyn L. Zimny ◽  
Roy Gregory
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Muscle ◽  
Adenosine Triphosphate ◽  
Ground Squirrel ◽  
Inorganic Phosphate ◽  
Liver Glycogen ◽  
High Energy ◽  
Ground Squirrels ◽  
High Energy Phosphates ◽  
High Energy Phosphate

Biochemical levels of inorganic phosphate, adenosine triphosphate, phosphocreatine and glycogen were determined on cardiac muscle, skeletal muscle and liver samples from hibernated 13-striped ground squirrels and those allowed to awaken for intervals of 7.5, 15 and 30 minutes. Cardiac muscle glycogen increases during hibernation apparently at the expense of skeletal muscle and liver glycogen. Glycolysis occurs in these tissues during early arousal, followed later by glycogenesis. Adenosine triphosphate is maintained in both cardiac and skeletal muscle during hibernation and is used as an energy source during arousal. It appears that glycolysis is important in resynthesizing phosphocreatine. From this study of periods of relatively low and high metabolic demands we conclude that phosphocreatine is a ‘transport’ form of high-energy phosphate forming adenosine triphosphate from the phosphate pool when and where needed in the cycle of intermediary metabolism.

Hibernation and cold storage effects on phosphates in hamster blood

1960 ◽  
Vol 199 (1) ◽  
pp. 195-197 ◽  
Author(s):  
Mary Anne Brock
Keyword(s):  
Cold Storage ◽  
Inorganic Phosphate ◽  
Mesocricetus Auratus ◽  
Organic Phosphate ◽  
Red Cells ◽  
The Other ◽  
Golden Hamsters ◽  
Storage Effects ◽  
Phosphate Compounds

No significant changes from control levels were found in phosphate fractions of erythrocytes and plasma analyzed in cold-exposed golden hamsters ( Mesocricetus auratus). The effect of depressed temperature on red cells after 3 days of hibernation or storage was reflected in decreased easily hydrolyzable phosphate and increased difficultly hydrolyzable phosphate. These changes were interpreted as probably the result of diminished removal of triosephosphate followed by an increase in phosphorylated hexoses. ADP was not rephosphorylated at a rate equal to the esterification of hexoses by ATP, and a diminution of ATP occurred. Furthermore, significant increases in inorganic phosphate occurred in hibernator's erythrocytes and plasma. These were accounted for in the plasma as the result of phosphatase action on phospholipids. In erythrocytes, the other organic phosphate compounds must contribute to this fraction. Six hours following the initiation of arousal from hibernation, an almost complete return to control values for phosphate fractions was observed.

Endurance-Trained and Untrained Skeletal Muscle Bioenergetics Observed With Magnetic Resonance Spectroscopy

1996 ◽  
Vol 21 (4) ◽  
pp. 251-263 ◽  
Author(s):  
Bart M. Guthrie ◽  
Simon P. Frostick ◽  
David J. Mikulis ◽  
K. Wayne Marshall ◽  
Jack Goodman ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Intracellular Ph ◽  
Adenosine Triphosphate ◽  
Inorganic Phosphate ◽  
Isometric Exercise ◽  
Oxidative Capacity ◽  
Resonance Spectroscopy ◽  
Trained Subjects

Resting and submaximal isometric exercise 31P magnetic resonance spectroscopy (MRS) was carried out on 7 endurance-trained males (26.0 ± 3 yrs) and 7 sedentary males (27.0 ± 4 yrs). Spectral analysis provided peak areas of phosphocreatine (PCr), inorganic phosphate (Pi), adenosine triphosphate (ATP), and the chemical shift of Pi relative to PCr. The ratio of PCr/Pi was moderately lower during rest (preexercise p =.13, postexercise p =.18), and significantly higher during exercise (p < .05) in the trained subjects. Intracellular pH patterns were the same for both groups; a transient alkalosis was observed at the onset of exercise with a return to resting levels after 2 min. Differences suggest improved ATP resynthesis rate in the trained subjects during exercise. Intracellular pH changes can be attributed to the utilization of hydrogen ions that accompany PCr hydrolysis during work. The findings are congruent with previous reports indicating a superior oxidative capacity in trained skeletal muscle. Key words: 31P MRS, isometric exercise, phosphocreatine, inorganic phosphate, adenosine triphosphate, intracellular pH

Inorganic phosphate uptake in Trypanosoma cruzi is coupled to K+ cycling and to active Na+ extrusion

2013 ◽  
Vol 1830 (8) ◽  
pp. 4265-4273 ◽  
Author(s):  
C.F. Dick ◽  
A.L.A. Dos-Santos ◽  
D. Majerowicz ◽  
L.S. Paes ◽  
N.L. Giarola ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Inorganic Phosphate ◽  
Phosphate Uptake
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