title: Elimination of glucose contamination from adipocyte glycogen extracts.
abstract: Glycogen was quantified in rat adipocytes by isolation using conventional KOH digestion and ethanol precipitation, followed by hydrolysis and spectrophotometric assay of the glucose product. A concentration of 0.193+/-0.020 micromol glucosyl units/10(6)cells was recorded. When this procedure was modified by including a 4h incubation with glucose oxidase prior to glycogen hydrolysis, the glycogen concentration was found to be 0.055+/-0.008 micromol glucosyl units/10(6) cells. Therefore in adipocytes, conventional glycogen assays give substantial overestimates due to incomplete removal of glucose during glycogen isolation. Contaminant glucose can be scavenged in a simple manner by incubation with glucose oxidase prior to glycogen hydrolysis.
authors.affiliation: Center for Neurosciences and Cell Biology, Department of Zoology, University of Coimbra, 3004-517 Coimbra, Portugal.
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Nunes
authors.forename: Eugénia
authors.initials: E
authors.lastname: Carvalho
authors.forename: John G
authors.initials: JG
authors.lastname: Jones
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D005087:Glucan 1,4-alpha-Glucosidase / Q000378:metabolism; D005947:Glucose / Q000737:chemistry / Q000302:isolation & purification*; D005949:Glucose Oxidase / Q000378:metabolism; D006003:Glycogen / Q000737:chemistry* / Q000378:metabolism; D006868:Hydrolysis; D008297:Male; D051381:Rats; D017208:Rats, Wistar
chemical_list: D006003:Glycogen; D005949:Glucose Oxidase; D005087:Glucan 1,4-alpha-Glucosidase; D005947:Glucose