De novo synthesis of adenine nucleotides in different skeletal muscle fiber types

1988 ◽  
Vol 255 (3) ◽  
pp. C271-C277 ◽  
Author(s):  
P. C. Tullson ◽  
H. B. John-Alder ◽  
D. A. Hood ◽  
R. L. Terjung
Keyword(s):  
Skeletal Muscle ◽  
De Novo ◽  
Adenine Nucleotide ◽  
Adenine Nucleotides ◽  
Vastus Lateralis ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
De Novo Synthesis ◽  
Red Muscle ◽  
Fast Twitch

Management of adenine nucleotide catabolism differs among skeletal muscle fiber types. This study evaluated whether there are corresponding differences in the rates of de novo synthesis of adenine nucleotide among fiber type sections of skeletal muscle using an isolated perfused rat hindquarter preparation. Label incorporation into adenine nucleotides from the [1-14C]glycine precursor was determined and used to calculate synthesis rates based on the intracellular glycine specific radioactivity. Results show that intracellular glycine is closely related to the direct precursor pool. Rates of de novo synthesis were highest in fast-twitch red muscle (57.0 +/- 4.0, 58.2 +/- 4.4 nmol.h-1.g-1; deep red gastrocnemius and vastus lateralis), relatively high in slow-twitch red muscle (47.0 +/- 3.1; soleus), and low in fast-twitch white muscle (26.1 +/- 2.0 and 21.6 +/- 2.3; superficial white gastrocnemius and vastus lateralis). Rates for four mixed muscles were intermediate, ranging between 32.3 and 37.3. Specific de novo synthesis rates exhibited a strong correlation (r = 0.986) with muscle section citrate synthase activity. Turnover rates (de novo synthesis rate/adenine nucleotide pool size) were highest in high oxidative muscle (0.82-1.06%/h), lowest in low oxidative muscle (0.30-0.35%/h), and intermediate in mixed muscle (0.44-0.55%/h). Our results demonstrate that differences in adenine nucleotide management among fiber types extends to the process of de novo adenine nucleotide synthesis.

Purine salvage to adenine nucleotides in different skeletal muscle fiber types

2001 ◽  
Vol 91 (1) ◽  
pp. 231-238 ◽  
Author(s):  
Jeffrey J. Brault ◽  
Ronald L. Terjung
Keyword(s):  
Skeletal Muscle ◽  
De Novo ◽  
Adenine Nucleotide ◽  
Fiber Type ◽  
High Rate ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
De Novo Synthesis ◽  
Purine Salvage ◽  
Fast Twitch

Rates of purine salvage of adenine and hypoxanthine into the adenine nucleotide (AdN) pool of the different skeletal muscle phenotype sections of the rat were measured using an isolated perfused hindlimb preparation. Tissue adenine and hypoxanthine concentrations and specific activities were controlled over a broad range of purine concentrations, ranging from 3 to 100 times normal, by employing an isolated rat hindlimb preparation perfused at a high flow rate. Incorporation of [3H]adenine or [3H]hypoxanthine into the AdN pool was not meaningfully influenced by tissue purine concentration over the range evaluated (∼0.10–1.6 μmol/g). Purine salvage rates were greater ( P < 0.05) for adenine than for hypoxanthine (35–55 and 20–30 nmol · h−1 · g−1, respectively) and moderately different ( P < 0.05) among fiber types. The low-oxidative fast-twitch white muscle section exhibited relatively low rates of purine salvage that were ∼65% of rates in the high-oxidative fast-twitch red section of the gastrocnemius. The soleus muscle, characterized by slow-twitch red fibers, exhibited a high rate of adenine salvage but a low rate of hypoxanthine salvage. Addition of ribose to the perfusion medium increased salvage of adenine (up to 3- to 6-fold, P < 0.001) and hypoxanthine (up to 6- to 8-fold, P < 0.001), depending on fiber type, over a range of concentrations up to 10 mM. This is consistent with tissue 5-phosphoribosyl-1-pyrophosphate being rate limiting for purine salvage. Purine salvage is favored over de novo synthesis, inasmuch as delivery of adenine to the muscle decreased ( P < 0.005) de novo synthesis of AdN. Providing ribose did not alter this preference of purine salvage pathway over de novo synthesis of AdN. In the absence of ribose supplementation, purine salvage rates are relatively low, especially compared with the AdN pool size in skeletal muscle.

Adenine nucleotide synthesis in exercising and endurance-trained skeletal muscle

1991 ◽  
Vol 261 (2) ◽  
pp. C342-C347 ◽  
Author(s):  
P. C. Tullson ◽  
R. L. Terjung
Keyword(s):  
De Novo ◽  
Adenine Nucleotide ◽  
Energy State ◽  
High Energy ◽  
Strenuous Exercise ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
De Novo Synthesis ◽  
Nucleotide Synthesis ◽  
Fast Twitch

Strenuous exercise leads to increased efflux of purine nucleoside and base that should necessitate recovery of adenine nucleotides by either the de novo synthesis or salvage pathway. De novo synthesis of adenine nucleotide was measured in quiescent and contracting muscle of sedentary and exercise-trained rats using an isolated perfused hindquarter preparation. Synthesis rates were assessed by measuring the incorporation of [1-14C]glycine into adenine nucleotide in muscles of both resting and stimulated hindlimbs after 1 h of either low- or high-energy demand isometric contractions. In nonstimulated sedentary and trained muscles, rates of de novo synthesis were similar. The effect of muscle contractions on de novo synthesis varied among muscle fiber types. Contracting, nonfatigued fast-twitch muscle sections showed significant declines in de novo synthesis in both sedentary and trained groups. Rates in slow-twitch red fibers and fatigued fast-twitch white fiber sections were not different from rest. Supplementing the perfusate with 5 mM ribose caused de novo synthesis to rise three- to fourfold in each of the fiber sections. However, the response in synthesis rates due to exercise was similar with or without ribose supplementation. De novo synthesis does not increase during exercise but exhibits an unchanged or reduced rate depending on the expected energy balance within the cell. This would occur if the energy state of muscle exerts significant control over de novo synthesis of adenine nucleotide.

Mitochondrial reticulum in limb skeletal muscle

1986 ◽  
Vol 251 (3) ◽  
pp. C395-C402 ◽  
Author(s):  
S. P. Kirkwood ◽  
E. A. Munn ◽  
G. A. Brooks
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Vastus Lateralis ◽  
Skeletal Muscle Fiber ◽  
Muscle Fiber Types ◽  
Mitochondrial Morphology ◽  
Fiber Types ◽  
Fast Twitch ◽  
Mitochondrial Reticulum ◽  
Superficial Portion

High-voltage electron microscopy at 1,500 kV was used to examine mitochondrial morphology in three skeletal muscles of the rat. The soleus, deep portion of the vastus lateralis, and superficial portion of the vastus lateralis muscles were examined to represent slow-twitch oxidative, fast-twitch oxidative, glycolytic, and fast-twitch glycolytic skeletal muscle fiber types, respectively. Muscle samples were removed from six female Wistar rats. The tissues were fixed using standard electron microscopic techniques and were sectioned transversely with respect to muscle fiber orientation to approximately 0.5-micron thickness. The sections were stained on grids with uranyl acetate and Reynolds' lead citrate. Results revealed a mitochondrial reticulum in all three skeletal muscle fiber types. Stereological analyses of the electron micrographs were performed to measure volume densities and surface-to-volume ratios of mitochondria in the muscle samples. Cross-sectional volume densities of mitochondria in the soleus (15.5 +/- 1%) and deep portion of the vastus lateralis (16.1 +/- 2%) were significantly greater (P less than 0.05) than in the superficial portion of the vastus lateralis (8.7 +/- 1%). Surface-to-volume ratios of mitochondria were not significantly different between fiber types. It was concluded that the mitochondria in mammalian limb skeletal muscle are a reticulum, or network.

scholarly journals Cytoskeletal structure of skeletal muscle: identification of an intricate exosarcomeric microtubule lattice in slow- and fast-twitch muscle fibers.

1993 ◽  
Vol 41 (7) ◽  
pp. 1013-1021 ◽  
Author(s):  
S Boudriau ◽  
M Vincent ◽  
C H Côté ◽  
P A Rogers
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Vastus Lateralis ◽  
Muscle Fiber Types ◽  
Vastus Lateralis Muscle ◽  
Type I ◽  
Fiber Types ◽  
Mammalian Skeletal Muscle ◽  
Microtubule Network ◽  
Fast Twitch

We used immunochemical quantification and indirect immunofluorescence to investigate the cell content, distribution, and organization of microtubules in adult rat slow-twitch soleus and fast-twitch vastus lateralis muscles. An immunoblotting assay demonstrated that the soleus muscle (primarily Type I fibers) was found to have a 1.7-fold higher relative content of alpha-tubulin compared with the superficial portion of the vastus lateralis muscle (primarily Type IIb fibers). Both physiological muscle types revealed a complex arrangement of microtubules which displayed oblique, longitudinal, and transverse orientations within the sarcoplasmic space. The predominance of any one particular orientation varied significantly from one muscle tissue section to another. Nuclei were completely surrounded by a dense net-like structure of microtubules. Both muscle fiber types were found to possess a higher density of microtubules in the subsarcolemmal region. These microtubules followed the contour of the sarcolemma in slightly contracted fibers and showed a fine punctate appearance indicative of a restricted distribution. The immunofluorescence results indicate that microtubules are associated with the sarcolemma and therefore may form a part of the membrane cytoskeletal domain of the muscle fiber. We conclude that the microtubule network of the adult mammalian skeletal muscle fiber constitutes a bone fide component of the exosarcomeric cytoskeletal lattice domain along with the intermediate filaments, and as such could therefore participate in the mechanical integration of the various organelles of the myofibers during the contraction-relaxation cycle.

Uptake of chylomicron triglycerides by contracting skeletal muscle in rats

1980 ◽  
Vol 49 (5) ◽  
pp. 851-855 ◽  
Author(s):  
B. G. Mackie ◽  
G. A. Dudley ◽  
H. Kaciuba-Uscilko ◽  
R. L. Terjung
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Muscle Fiber Types ◽  
Muscle Stimulation ◽  
Fiber Types ◽  
Energy Needs ◽  
Red Muscle ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Fractional Uptake

The influence of muscle stimulation (3 Hz) on the uptake of exogenously administered chylomicron 14C-labeled triglycerides (14C-TG) in the three different muscle fiber types was evaluated in fed and fasted pentobarbital-anesthetized rats. The fractional uptake of 14C-TG in the nonstimulated muscles was lowest in the fast-twitch white, intermediate in the fast-twitch red, and highest in the slow-twitch red muscle fiber section. Fasting doubled the uptake in both high-oxidative red fibers. These 14C-TG uptakes were directly proportional (r = 0.993) to their respective activities of lipoprotein lipase in these fiber types of fed and fasted animals reported by others. Muscle stimulation caused a significant increase in the fractional 14C-TG uptake in all of the fiber types. Although the TG uptake could account for only a small fraction of the total energy needs of the working muscle, it could contribute to the turnover of endogenous TG, especially in the slow-twitch red fibers. Further, the estimated TG uptake rate is sufficient to replace endogenous TG loss with an overnight rest following exercise. These results suggest that plasma TG could play an important role in lipid metabolism, especially in the high-oxidative slow and fast muscle fiber types.

IMP reamination to AMP in rat skeletal muscle fiber types

1996 ◽  
Vol 270 (4) ◽  
pp. C1067-C1074 ◽  
Author(s):  
P. C. Tullson ◽  
P. G. Arabadjis ◽  
K. W. Rundell ◽  
R. L. Terjung
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
High Speed ◽  
De Novo ◽  
Degradation Products ◽  
Skeletal Muscle Fiber ◽  
Treadmill Running ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Fast Twitch

Inosine 5'-monophosphate (IMP) reamination in skeletal muscle fiber sections of the rat hindlimb was studied. High IMP concentrations were established during ischemic contractions in each fiber section: 3.1, 2.8, or 0.6 mumol/g in the fast-twitch white (FTW), fast-twitch red (FTR), and slow-twitch red (STR) muscle sections, respectively. Thereafter blood flow was restored and stimulation was discontinued to allow reamination of IMP. After 0, 2, 5, 10, 15, or 20 min of recovery, muscle sections were freeze-clamped and analyzed for metabolite contents. IMP was nearly fully reaminated after 10 and 20 min of recovery in STR and FTR muscles, respectively. Reamination in TW fibers was delayed and slower, with only 50% of the IMP reaminated after 20 min of recovery. Significant recovery (approximately 75%) of phosphocreatine occurs in each fiber section before the onset of reamination. Reamination was also evaluated after high-speed treadmill running with or without inhibition of reamination by hadacidin. Running resulted in large accumulations of IMP in FTW and FTR fibers (3.5 and 1.4 mumul/g, respectively); IMP in FTR fibers was higher with hadacidin treatment. Reamination after running was much greater in FTR than in FTW fibers and was associated with recovery of phosphocreatine. After running, the purine degradation products inosine and hypoxanthine were increased in FTW and FTR fibers in normal and hadacidin-treated animals. Plasma inosine, hypoxanthine, and urate increased after exercise; concentrations continued to increase if reamination was inhibited by hadacidin. These results demonstrate that when muscle IMP is increased, subsequent degradation and loss of purines occur. Rapid reamination should minimize the quantity of purine lost from muscle and limit the metabolic cost of replenishing purines by the de novo synthesis or salvage pathways.

Ammonia and IMP in different skeletal muscle fibers after exercise in rats

1980 ◽  
Vol 49 (6) ◽  
pp. 1037-1041 ◽  
Author(s):  
R. A. Meyer ◽  
G. A. Dudley ◽  
R. L. Terjung
Keyword(s):  
Skeletal Muscle ◽  
Vastus Lateralis ◽  
Muscle Fibers ◽  
Treadmill Running ◽  
Strenuous Exercise ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Glycolytic Intermediate ◽  
Lactate Levels ◽  
Fast Twitch

Adenosine 5'-monophosphate (AMP) deamination, estimated from inosine 5'-monophosphate (IMP) accumulation, was studied in the different skeletal muscle fiber types of untrained rats anesthetized with ether immediately after 4 min of treadmill running at 45 or 60 m/min. The adenylosuccinate synthetase-inhibitor hadacidin was administered (200 mg/kg ip) before exercise to block IMP reamination and, therefore, to provide a better assessment of IMP formation. The increases in blood ammonia after exercise (2.5- and 5-fold, respectively) were highly correlated (r = 0.93) with the increases in blood lactate levels (6- and 11-fold). At both speeds, IMP increased in fast-twitch but not in slow-twitch (soleus) muscle. Of the fast muscles, the increase in IMP was greatest (up to 4 mumol/g wet wt) in the white vastus lateralis (fast twitch, glycolytic), intermediate in the plantaris (mixed fibers), and lowest in the red vastus lateralis (fast twitch, oxidative glycolytic). The increases in IMP were coincident with nearly equivalent decreases in ATP. Hadacidin treatment resulted in a greater IMP accumulation after exercise in both fast-twitch types but not in the soleus. The results indicate that fast-twitch muscle fibers, particularly the fast-twitch glycolytic fibers, are the source of the ammonia produced during strenuous exercise.

Blood flow to different skeletal muscle fiber types during contraction

1983 ◽  
Vol 245 (2) ◽  
pp. H265-H275 ◽  
Author(s):  
B. G. Mackie ◽  
R. L. Terjung
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Oxidative Capacity ◽  
Skeletal Muscle Fiber ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Blood Flows ◽  
Fast Twitch

Blood flow to fast-twitch red (FTR), fast-twitch white (FTW), and slow-twitch red (STR) muscle fiber sections of the gastrocnemius-plantaris-soleus muscle group was determined using 15 +/- 3-microns microspheres during in situ stimulation in pentobarbital-anesthetized rats. Steady-state blood flows were assessed during the 10th min of contraction using twitch (0.1, 0.5, 1, 3, and 5 Hz) and tetanic (7.5, 15, 30, 60, and 120/min) stimulation conditions. In addition, an earlier blood flow determination was begun at 3 min (twitch series) or at 30 s (tetanic series) of stimulation. Blood flow was highest in the FTR (220-240 ml X min-1 X 100 g-1), intermediate in the STR (140), and lowest in the FTW (70-80) section during tetanic contraction conditions estimated to coincide with the peak aerobic function of each fiber type. These blood flows are fairly proportional to the differences in oxidative capacity among fiber types. Further, their absolute values are similar to those predicted from the relationship between blood flow and oxidative capacity found by others for dog and cat muscles. During low-frequency contraction conditions, initial blood flow to the FTR and STR sections were excessively high and not dependent on contraction frequency. However, blood flows subsequently decreased to values in keeping with the relative energy demands. In contrast, FTW muscle did not exhibit this time-dependent relative hyperemia. Thus, besides the obvious quantitative differences between skeletal muscle fiber types, there are qualitative differences in blood flow response during contractions. Our findings establish that, based on fiber type composition, a heterogeneity in blood flow distribution can occur within a whole muscle during contraction.

Influence of training on skeletal muscle enzymatic adaptations in normal and diabetic rats

1985 ◽  
Vol 249 (4) ◽  
pp. E360-E365 ◽  
Author(s):  
E. G. Noble ◽  
C. D. Ianuzzo
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Citrate Synthase ◽  
Diabetic Rats ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Marker Enzymes ◽  
Oxidative Potential ◽  
Hydroxyacyl Coa Dehydrogenase ◽  
Fast Twitch

Muscle homogenates representing slow-twitch oxidative, fast-twitch oxidative-glycolytic, fast-twitch glycolytic, and mixed fiber types were prepared from normal, diabetic, and insulin-treated diabetic rats. Diabetes was induced by injection of 80 mg . kg-1 of streptozotocin. The activities of citrate synthase, succinate dehydrogenase, and 3-hydroxyacyl-CoA dehydrogenase were employed as markers of oxidative potential, whereas phosphorylase, hexokinase, and phosphofructokinase activities were used as an indication of glycolytic capacity. Diabetes was associated with a general decrement in the activity of oxidative marker enzymes for all fiber types except the fast-twitch glycolytic fiber. In contrast, the fast-twitch glycolytic fibers demonstrated the greatest decline in glycolytic enzymatic activity. Insulin-treated animals, either trained or untrained, exhibited enzyme activities similar to their normal counterparts. Exercise training of diabetic rats mimicked the effect of insulin treatment and caused a near normalization of the activity of the marker enzymes. These findings suggest that the enzymatic potential of all skeletal muscle fiber types of diabetic rats may be normalized by exercise training even in the absence of significant amounts of insulin.

Effect of exercise on lipoprotein lipase activity in rat heart and skeletal muscle

1975 ◽  
Vol 229 (2) ◽  
pp. 394-397 ◽  
Author(s):  
J Borensztajn ◽  
MS Rone ◽  
SP Babirak ◽  
JA McGarr ◽  
LB Oscai
Keyword(s):  
Skeletal Muscle ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Plasma Triglyceride ◽  
Treadmill Running ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Lipoprotein Lipase Activity ◽  
Slow Twitch ◽  
Fast Twitch

Lipoprotein lipase activity was measured in the three skeletal muscle fiber types of untrained rats and in those of rats subjected to a 12-wk program of treadmill running. Lipoprotein lipase activity in slow-twitch red fibers was approximately 14- to 20-fold higher (P less than 0.001) than that in fast-twitch white and approximately 2-fold higher (P less than 0.001) than that in fast-twitch red fibers in the untrained animals. These results suggest that, in sedentary animals, mainly slow-twitch red and fast-twitch red fibers are capable of taking up plasma triglyceride fatty acids. Regularly performed endurance exercise resulted in significant increase (2- to 4.5-fold) in lipoprotein lipase activity in the three muscle fiber types examined. The increase in lipoprotein lipase activity in response to treadmill running suggests that exercise increases the capacity of these fibers to take up and oxidize plasma triglyceride fatty acids. Cardiac muscle did not undergo an exercise-induced increase in the levels of activity of lipoprotein lipase similar to that seen in skeletal muscle.

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