|
|
||||||||
1 Exercise Physiology and Metabolism Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, Texas 78712; and 2 Division of Geriatrics and Gerontology, Washington University of Medicine, St. Louis, Missouri 63110
We examined the
effects of amylin on
3-O-methyl-D-glucose
(3-O-MG) transport in perfused rat
hindlimb muscle under hyperinsulinemic (350 µU/ml, 2,100 pmol/l)
conditions. Amylin at 100 nmol/l concentration inhibited
3-O-MG transport relative to control
in all three basic muscle fiber types. Transport decreased in
slow-twitch oxidative (from 5.65 ± 1.13 to 3.46 ± 0.71 µmol · g
1 · h
1),
fast-twitch oxidative (from 6.84 ± 0.90 to 4.84 ± 0.76 µmol · g
1 · h
1),
and fast-twitch glycolytic (from 1.27 ± 0.20 to 0.60 ± 0.05 µmol · g
1 · h
1)
muscle. Amylin inhibition of insulin-stimulated glucose transport in
skeletal muscle was accompanied by a 433 ± 72% increase in intracellular glucose 6-phosphate
(G-6-P) despite the absence of
extracellular glucose. The source of hexose units for the formation and
maintenance of G-6-P was likely
glycogen. Amylin increased glycogenolysis, increased lactate formation,
and decreased glycogen synthase activity. Furthermore, the kinetics of
glycogen synthase suggest that this enzyme may control intracellular
G-6-P concentration. Despite the large
increase in G-6-P, no detectable
increase in uridine
diphosphate-N-acetylhexosamines
occurred, suggesting that the proposed glucosamine pathway may not be
involved in transport inhibition. However, decreases in uridine
diphosphate hexoses were detected. Therefore, uridine or
hexosamine-based metabolites may be involved in amylin action.
glucosamine; glycogen synthase; glucose 6-phosphate; lactate; uridine diphosphate-N-acetylhexosamine; uridine diphosphate hexose
This article has been cited by other articles:
![]() |
C. S. Choi, F. N. Lee, and J. H. Youn Free Fatty Acids Induce Peripheral Insulin Resistance Without Increasing Muscle Hexosamine Pathway Product Levels in Rats Diabetes, February 1, 2001; 50(2): 418 - 424. [Abstract] [Full Text] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |