{"doi":"10.1152/ajpendo.00424.2006","title":"Human brain glycogen content and metabolism: implications on its role in brain energy metabolism","abstract":"<jats:p> The adult brain relies on glucose for its energy needs and stores it in the form of glycogen, primarily in astrocytes. Animal and culture studies indicate that brain glycogen may support neuronal function when the glucose supply from the blood is inadequate and/or during neuronal activation. However, the concentration of glycogen and rates of its metabolism in the human brain are unknown. We used in vivo localized <jats:sup>13</jats:sup>C-NMR spectroscopy to measure glycogen content and turnover in the human brain. Nine healthy volunteers received intravenous infusions of [1-<jats:sup>13</jats:sup>C]glucose for durations ranging from 6 to 50 h, and brain glycogen labeling and washout were measured in the occipital lobe for up to 84 h. The labeling kinetics suggest that turnover is the main mechanism of label incorporation into brain glycogen. Upon fitting a model of glycogen metabolism to the time courses of newly synthesized glycogen, human brain glycogen content was estimated at ∼3.5 μmol/g, i.e., three- to fourfold higher than free glucose at euglycemia. Turnover of bulk brain glycogen occurred at a rate of 0.16 μmol·g<jats:sup>−1</jats:sup>·h<jats:sup>−1</jats:sup>, implying that complete turnover requires 3–5 days. Twenty minutes of visual stimulation ( n = 5) did not result in detectable glycogen utilization in the visual cortex, as judged from similar [<jats:sup>13</jats:sup>C]glycogen levels before and after stimulation. We conclude that the brain stores a substantial amount of glycogen relative to free glucose and metabolizes this store very slowly under normal physiology. </jats:p>","journal":"American Journal of Physiology-Endocrinology and Metabolism","year":2007,"id":675457,"datarank":4.274399224521369,"base_score":4.969813299576001,"endowment":4.969813299576001,"self_citation_contribution":0.7454719949364003,"citation_network_contribution":3.5289272295849687,"self_endowment_contribution":0.7454719949364003,"citer_contribution":3.5289272295849687,"corpus_percentile":null,"corpus_rank":null,"citation_count":143,"citer_count":125,"citers_with_citation_signal":106,"citers_with_endowment":106,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":402153,"name":"Elizabeth R. 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However, the concentration of glycogen and rates of its metabolism in the human brain are unknown. We used in vivo localized <jats:sup>13</jats:sup>C-NMR spectroscopy to measure glycogen content and turnover in the human brain. Nine healthy volunteers received intravenous infusions of [1-<jats:sup>13</jats:sup>C]glucose for durations ranging from 6 to 50 h, and brain glycogen labeling and washout were measured in the occipital lobe for up to 84 h. The labeling kinetics suggest that turnover is the main mechanism of label incorporation into brain glycogen. Upon fitting a model of glycogen metabolism to the time courses of newly synthesized glycogen, human brain glycogen content was estimated at ∼3.5 μmol/g, i.e., three- to fourfold higher than free glucose at euglycemia. Turnover of bulk brain glycogen occurred at a rate of 0.16 μmol·g<jats:sup>−1</jats:sup>·h<jats:sup>−1</jats:sup>, implying that complete turnover requires 3–5 days. Twenty minutes of visual stimulation ( n = 5) did not result in detectable glycogen utilization in the visual cortex, as judged from similar [<jats:sup>13</jats:sup>C]glycogen levels before and after stimulation. We conclude that the brain stores a substantial amount of glycogen relative to free glucose and metabolizes this store very slowly under normal physiology. </jats:p>","is_dataset_classified":null,"base_score":4.969813299576001,"endowment":4.969813299576001,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"17132822","pmcid":null,"openalex_id":"https://openalex.org/W2136544803","authors":[],"funders":[{"funder_name":"NCRR NIH HHS","grant_id":"M01-RR-00400","title":null},{"funder_name":"NCRR NIH HHS","grant_id":"P41-RR-08079","title":null},{"funder_name":"NINDS NIH HHS","grant_id":"R01-NS-38672","title":null},{"funder_name":"NINDS NIH HHS","grant_id":"R21-NS-45519","title":null},{"funder_name":"National Institutes of Health","grant_id":"5P41RR008079-05","title":"C13 SPECTROSCOPY W/ PROTON DECOUPLING IN HUMANS AT 4 TESLA"},{"funder_name":"National Institutes of Health","grant_id":"5M01RR000400-26","title":"GENERAL CLINICAL RESEARCH CENTER"},{"funder_name":"National Institutes of Health","grant_id":"1R21NS045519-01","title":"NMR Measurements of Human Brain Glycogen Metabolism"}],"total_grants":7,"fwci":1.7534,"citation_percentile":0.83129112,"influential_citations":0,"citation_trend":[{"year":2012,"count":9},{"year":2013,"count":7},{"year":2014,"count":8},{"year":2015,"count":11},{"year":2016,"count":5},{"year":2017,"count":5},{"year":2018,"count":6},{"year":2019,"count":8},{"year":2020,"count":5},{"year":2021,"count":6},{"year":2022,"count":6},{"year":2023,"count":7},{"year":2024,"count":7},{"year":2025,"count":6},{"year":2026,"count":1}],"oa_status":"green","license":"other-oa","oa_locations":[{"url":"https://archive-ouverte.unige.ch/unige:32938","host_type":"repository"},{"url":"https://archive-ouverte.unige.ch/unige:32938","host_type":"repository"},{"url":"https://www.physiology.org/doi/pdf/10.1152/ajpendo.00424.2006","host_type":"publisher"},{"url":"https://doi.org/10.1152/ajpendo.00424.2006","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/17132822","host_type":"repository"},{"url":"http://infoscience.epfl.ch/record/177477","host_type":"repository"},{"url":"https://archive-ouverte.unige.ch/unige:32938/ATTACHMENT01","host_type":""},{"url":"https://dx.doi.org/10.1152/ajpendo.00424.2006","host_type":""},{"url":"https://hdl.handle.net/20.500.14299/80845","host_type":""}],"fields_of_study":["Neuroscience and Neuropharmacology Research","Neurological disorders and treatments","Epilepsy research and treatment","0301 basic medicine","03 medical and health sciences","0302 clinical medicine","Adult","Brain","Brain Chemistry","Energy Metabolism","Female","Glucose","Glycogen","Humans","Magnetic Resonance Imaging","Male","Middle Aged","Models, Theoretical","Photic Stimulation"],"mesh_terms":["Adult","Brain","Brain Chemistry","Energy Metabolism","Female","Glucose","Glycogen","Humans","Magnetic Resonance Imaging","Male","Middle Aged","Models, Theoretical","Photic Stimulation"],"keywords":["Glycogen","Endocrinology","Internal medicine","Glycogen synthase","Metabolism","Human brain","Biology","Stimulation","Carbohydrate metabolism","Biochemistry","Chemistry","Medicine","Neuroscience","Adult","Brain Chemistry","Male","616.0757","Brain","Middle Aged","Models, Theoretical","Magnetic Resonance Imaging","Glucose/administration & dosage/pharmacokinetics","Glucose","Glycogen/analysis/metabolism/physiology","Brain/metabolism","Humans","Female","Energy Metabolism","Photic Stimulation"],"sdg_mappings":[{"sdg_number":3,"sdg_label":"3. 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