PMID- 11350781
OWN - NLM
STAT- MEDLINE
DCOM- 20010614
LR  - 20171213
IS  - 0193-1849 (Print)
IS  - 0193-1849 (Linking)
VI  - 280
IP  - 6
DP  - 2001 Jun
TI  - Functional limitations to glucose uptake in muscles comprised of different fiber 
      types.
PG  - E994-9
AB  - Skeletal muscle glucose uptake requires delivery of glucose to the sarcolemma, 
      transport across the sarcolemma, and the irreversible phosphorylation of glucose 
      by hexokinase (HK) inside the cell. Here, a novel method was used in the 
      conscious rat to address the roles of these three steps in controlling the rate 
      of glucose uptake in soleus, a muscle comprised of type I fibers, and two muscles 
      comprised of type II fibers. Experiments were performed on conscious rats under 
      basal conditions or during hyperinsulinemic euglycemic clamps. Rats received 
      primed, constant infusions of 3-O-methyl-[3H]glucose (3-O-MG) and 
      [1-14C]mannitol. Total muscle glucose concentration and the steady-state ratio of 
      intracellular to extracellular 3-O-MG concentration, which distributes based on 
      the transsarcolemmal glucose gradient (TSGG), were used to calculate glucose 
      concentrations at the inner and outer sarcolemmal surfaces ([G](im) and [G](om), 
      respectively) in muscle. Muscle glucose uptake was much lower in muscle comprised 
      of type II fibers than in soleus under both basal and insulin-stimulated 
      conditions. Under all conditions, the TSGG in type II muscle exceeded that in 
      soleus, indicating that glucose transport plays a more important role to limit 
      glucose uptake in type II muscle. Although hyperinsulinemia increased [G](im) in 
      soleus, indicating that phosphorylation was a limiting factor, type II muscle was 
      limited primarily by glucose delivery and glucose transport. In conclusion, the 
      relative importance of glucose delivery, transport, and phosphorylation in 
      controlling the rate of insulin-stimulated muscle glucose uptake varies between 
      muscle fiber types, with glucose delivery and transport being the primary 
      limiting factors in type II muscle.
FAU - Halseth, A E
AU  - Halseth AE
AD  - Department of Molecular Physiology and Biophysics, Vanderbilt University School 
      of Medicine, Nashville, Tennessee 37232, USA. amy.e.halseth@pharmacia.com
FAU - Bracy, D P
AU  - Bracy DP
FAU - Wasserman, D H
AU  - Wasserman DH
LA  - eng
GR  - R01 DK-54902/DK/NIDDK NIH HHS/United States
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Am J Physiol Endocrinol Metab
JT  - American journal of physiology. Endocrinology and metabolism
JID - 100901226
RN  - 0 (Carbon Radioisotopes)
RN  - 0 (Diuretics, Osmotic)
RN  - 0 (Hypoglycemic Agents)
RN  - 0 (Insulin)
RN  - 10028-17-8 (Tritium)
RN  - 146-72-5 (3-O-Methylglucose)
RN  - 3OWL53L36A (Mannitol)
RN  - 9G2MP84A8W (Deoxyglucose)
SB  - IM
MH  - 3-O-Methylglucose/*pharmacokinetics
MH  - Animals
MH  - Carbon Radioisotopes
MH  - Deoxyglucose/pharmacokinetics
MH  - Diuretics, Osmotic/pharmacokinetics
MH  - Energy Metabolism/drug effects/physiology
MH  - Glucose Clamp Technique
MH  - Hypoglycemic Agents/pharmacology
MH  - Insulin/pharmacology
MH  - Male
MH  - Mannitol/pharmacokinetics
MH  - Muscle Fibers, Fast-Twitch/*metabolism
MH  - Muscle Fibers, Slow-Twitch/*metabolism
MH  - Muscle, Skeletal/cytology/*metabolism
MH  - Phosphorylation
MH  - Rats
MH  - Rats, Sprague-Dawley
MH  - Tritium
EDAT- 2001/05/15 10:00
MHDA- 2001/06/23 10:01
CRDT- 2001/05/15 10:00
PHST- 2001/05/15 10:00 [pubmed]
PHST- 2001/06/23 10:01 [medline]
PHST- 2001/05/15 10:00 [entrez]
AID - 10.1152/ajpendo.2001.280.6.E994 [doi]
PST - ppublish
SO  - Am J Physiol Endocrinol Metab. 2001 Jun;280(6):E994-9. doi: 
      10.1152/ajpendo.2001.280.6.E994.