PMID- 17311895
OWN - NLM
STAT- MEDLINE
DCOM- 20070730
LR  - 20180109
IS  - 0193-1849 (Print)
IS  - 0193-1849 (Linking)
VI  - 292
IP  - 6
DP  - 2007 Jun
TI  - Glycogenin protein and mRNA expression in response to changing glycogen 
      concentration in exercise and recovery.
PG  - E1815-22
AB  - Glycogenin (GN-1) is essential for the formation of a glycogen granule; however, 
      rarely has it been studied when glycogen concentration changes in exercise and 
      recovery. It is unclear whether GN-1 is degraded or is liberated and exists as 
      apoprotein (apo)-GN-1 (unglycosylated). To examine this, we measured GN-1 protein 
      and mRNA level at rest, at exhaustion (EXH), and during 5 h of recovery in which 
      the rate of glycogen restoration was influenced by carbohydrate (CHO) provision. 
      Ten males cycled (65% VO2 max) to volitional EXH (117.8 +/- 4.2 min) on two 
      separate occasions. Subjects were administered carbohydrate (CHO; 1 
      g.kg(-1).h(-1) Gatorlode) or water [placebo (PL)] during 5 h of recovery. Muscle 
      biopsies were taken at rest, at EXH, and following 30, 60, 120, and 300 min of 
      recovery. At EXH, total glycogen concentration was reduced (P < 0.05). However, 
      GN-1 protein and mRNA content did not change. By 5 h of recovery, glycogen was 
      resynthesized to approximately 60% of rest in the CHO trial and remained 
      unchanged in the PL trial. GN-1 protein and mRNA level did not increase during 
      recovery in either trial. We observed modest amounts of apo-GN-1 at EXH, 
      suggesting complete degradation of some granules. These data suggest that GN-1 is 
      conserved, possibly as very small, or nascent, granules when glycogen 
      concentration is low. This would provide the ability to rapidly restore glycogen 
      during early recovery.
FAU - Wilson, Rhonda J
AU  - Wilson RJ
AD  - Department of Human Health and Nutritional Sciences, University of Guelph, 
      Guelph, ON, Canada N1G 2W1. rjwilson@uoguelph.ca
FAU - Gusba, Jenny E
AU  - Gusba JE
FAU - Robinson, Deborah L
AU  - Robinson DL
FAU - Graham, Terry E
AU  - Graham TE
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20070220
PL  - United States
TA  - Am J Physiol Endocrinol Metab
JT  - American journal of physiology. Endocrinology and metabolism
JID - 100901226
RN  - 0 (Blood Glucose)
RN  - 0 (Carbohydrates)
RN  - 0 (Glycoproteins)
RN  - 0 (Insulin)
RN  - 0 (RNA, Messenger)
RN  - 0 (glycogenin)
RN  - 9005-79-2 (Glycogen)
RN  - EC 2.4.1.- (Glucosyltransferases)
SB  - IM
MH  - Adult
MH  - Bicycling
MH  - Blood Glucose/metabolism
MH  - Carbohydrates/pharmacology
MH  - Exercise/*physiology
MH  - Glucosyltransferases/*genetics/*metabolism
MH  - Glycogen/genetics/*metabolism
MH  - Glycoproteins/*genetics/*metabolism
MH  - Humans
MH  - Immunoblotting
MH  - Insulin/blood
MH  - Male
MH  - Muscle, Skeletal/*metabolism
MH  - Osmolar Concentration
MH  - Physical Endurance/physiology
MH  - RNA, Messenger/*metabolism
MH  - Time Factors
EDAT- 2007/02/22 09:00
MHDA- 2007/07/31 09:00
CRDT- 2007/02/22 09:00
PHST- 2007/02/22 09:00 [pubmed]
PHST- 2007/07/31 09:00 [medline]
PHST- 2007/02/22 09:00 [entrez]
AID - 00598.2006 [pii]
AID - 10.1152/ajpendo.00598.2006 [doi]
PST - ppublish
SO  - Am J Physiol Endocrinol Metab. 2007 Jun;292(6):E1815-22. doi: 
      10.1152/ajpendo.00598.2006. Epub 2007 Feb 20.