| Changes in ATP, phosphocreatine, and 16 metabolites in muscle stimulated for up to 96 hours. | |
MedLine Citation:
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PMID: 8897822 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Rabbit tibialis anterior muscles were stimulated continuously at 10 Hz for periods ranging from 2 min to 96 h and were analyzed for energy reserves and metabolic intermediates. Glycogen, ATP and phosphocreatine fell rapidly during the first 5 min of stimulation. Glycogen continued to fall to very low levels, whereas ATP and phosphocreatine rose, reaching 70% of control by 1 h, despite ongoing stimulation. After 2 h, glycogen also increased, regaining control levels in 4 days. Glucose rose to 4.5 times control in 30 min and still exceeded 2.5 times control at 24 h. In the first 2 min, glycolytic intermediates, glucose 6-phosphate (G-6-P), fructose 1,6-bisphosphate, lactate, and pyruvate more than doubled and then returned to control levels or below. Malate and 3-glycerophosphate rose 600 and 200%, respectively. Both of these compounds participate in shuttling reducing equivalents from cytoplasm into mitochondria. Citrate and alpha-ketoglutarate underwent much more modest changes. Glucose 1,6-bisphosphate (G-1,6-P2) fell to one-third of control by 2 h and then rose dramatically at 4 h. At 4 days it was still twice control. The 6-phosphogluconate (6PG) doubled at 2 min, then rose to 12 times control at 2 h, fell somewhat, and peaked at 16 times control at 24 h. Aspartate and alanine both exhibited a biphasic rise in concentration, whereas glutamate fell to 30% in 15 min and rose slowly after 4 h. The rise in glucose was interpreted to be the consequence of rapid glycogenolysis together with inhibition of hexokinase by G-1,6-P2 and elevated G-6-P. Paradoxically, glycogen resynthesis apparently occurred when the glycogen synthase stimulator, G-6-P, was very low, and the glycolysis stimulator, G-1,6-P2, was high. Although G-1,6-P2 is an inhibitor of 6PG dehydrogenase, the timing of the changes in G-1,6-P2 and 6PG levels suggests that the accumulation of 6PG was initiated by some other influence. |
Authors:
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S Salmons; J C Jarvis; C N Mayne; M M Chi; J K Manchester; D B McDougal; O H Lowry |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: The American journal of physiology Volume: 271 ISSN: 0002-9513 ISO Abbreviation: Am. J. Physiol. Publication Date: 1996 Oct |
Date Detail:
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Created Date: 1996-12-16 Completed Date: 1996-12-16 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0370511 Medline TA: Am J Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: C1167-71 Citation Subset: IM |
Affiliation:
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Department of Human Anatomy and Cell Biology, University of Liverpool, United Kingdom. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adenosine Triphosphate
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metabolism* Animals Electric Stimulation Energy Metabolism Female Male Muscles / metabolism* Phosphocreatine / metabolism* Rabbits Time Factors |
| Grant Support | |
ID/Acronym/Agency:
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NS-08862/NS/NINDS NIH HHS; NS-24719/NS/NINDS NIH HHS |
| Chemical | |
Reg. No./Substance:
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56-65-5/Adenosine Triphosphate; 67-07-2/Phosphocreatine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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