title: Changes in glycogen structure over feeding cycle sheds new light on blood-glucose control.
abstract: Liver glycogen, a highly branched polymer of glucose, is important for maintaining blood-glucose homeostasis. It was recently shown that db/db mice, a model for Type 2 diabetes, are unable to form the large composite glycogen α particles present in normal, healthy mice. In this study, the structure of healthy mouse-liver glycogen over the diurnal cycle was characterized using size exclusion chromatography and transmission electron microscopy. Glycogen was found to be formed as smaller β particles, and then only assembled into large α particles, with a broad size distribution, significantly after the time when glycogen content had reached a maximum. This pathway, missing in diabetic animals, is likely to give optimal blood-glucose control during the daily feeding cycle. Lack of this control may contribute to, or result from, diabetes. This discovery suggests novel approaches to diabetes management.
authors.affiliation: Tongji School of Pharmacy, Huazhong University of Science and Technology , Wuhan, Hubei 430030, China.
authors.forename: Mitchell A
authors.initials: MA
authors.lastname: Sullivan
authors.forename: Samuel T N
authors.initials: ST
authors.lastname: Aroney
authors.forename: Shihan
authors.initials: S
authors.lastname: Li
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: Warren
authors.forename: Jin Suk
authors.initials: JS
authors.lastname: Joo
authors.forename: Ka Sin
authors.initials: KS
authors.lastname: Mak
authors.forename: David I
authors.initials: DI
authors.lastname: Stapleton
authors.forename: Kim S
authors.initials: KS
authors.lastname: Bell-Anderson
authors.forename: Robert G
authors.initials: RG
authors.lastname: Gilbert
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D002850:Chromatography, Gel; D002940:Circadian Rhythm; D004041:Dietary Fats / Q000008:administration & dosage*; D006003:Glycogen / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D008099:Liver / Q000737:chemistry / Q000378:metabolism; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D046529:Microscopy, Electron, Transmission
chemical_list: D001786:Blood Glucose; D004041:Dietary Fats; D006003:Glycogen