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Glucose uptake and glycogen levels are increased in pig heart after repetitive ischemia
Ist Teil von
American journal of physiology. Heart and circulatory physiology, 2002-01, Vol.282 (1), p.H205-H211
Ort / Verlag
United States
Erscheinungsjahr
2002
Quelle
Electronic Journals Library
Beschreibungen/Notizen
1 Veterans Affairs Medical Center, Minneapolis 55417;
2 Department of Biochemistry, University of Minnesota,
Minneapolis, Minnesota 55455; and 3 Department of
Anesthesia, Henry Ford Hospital, Detroit, Michigan 48202
Repetitive myocardial
ischemia increases glucose uptake, but the effect on glycogen
is unclear. Thirteen swine instrumented with a hydraulic occluder on
the circumflex (Cx) artery underwent 10-min occlusions twice per day
for 4 days. After 24 h postfinal ischemia and in the fasted
state, echocardiogram and positron emission tomography imaging for
blood flow ([ 13 N]-ammonia) and
2-[ 18 F]fluoro-2-deoxy- D -glucose (FDG) uptake
were obtained. Tissue was then collected for ATP, creatine phosphate
(CP), glycogen, and glucose transporter-4 content, and hexokinase
activity. After reperfusion, regional function and CP-to-ATP ratios in
the Cx and remote regions were similar. Despite the absence of
stunning, the Cx region demonstrated higher glycogen levels (33 ± 11 vs. 24 ± 11 µmol/g; P < 0.05), and this
increase correlated well with the increase in FDG uptake
( r 2 = 0.78; P < 0.01).
Hexokinase activity was also increased relative to remote regions
(0.62 ± 0.29 vs. 0.37 ± 0.19 IU/g; P < 0.05), with no difference in GLUT-4 content. In summary, 24 h
after repetitive ischemia, glucose uptake and glycogen levels
are increased at a time that functional and bioenergetic markers of
stunning have recovered. The significant correlation between glycogen
content and FDG accumulation in the postischemic region
suggests that increased rates of glucose transport and/or
phosphorylation are linked to increased glycogen levels in hearts
subjected to repetitive bouts of ischemia.
myocardial ischemia; stunning; glucose transporter-4; 2-[ 18 F]fluoro-2-deoxy- D -glucose; hexokinase