Metabolism of myocardial glycogen during ischemia and reperfusion
Camici, P.; Lorenzoni, R.; Bailey, I.A.
Cardiologia 31(7): 517-520
1986
ISSN/ISBN: 0393-1978 PMID: 3568045 Document Number: 268350
As previously reported the presence and location of acute myocardial ischemia in patients with effort angina could be demonstrated by the glucose (G) analogue 18F-deoxyglucose (FDG) and positron computed tomography. An increased FDG uptake was observed in the ischemic region during the recovery from the stress test when all the indices of ischemia were back to normal. To ascertain if changes in glygogen (GL) metabolism could explain the above finding we measured myocardial GL content in isolated perfused working rat hearts during control (C), after 15 min of global ischemia (I) and following reperfusion (R). The incorporation of exogenous G into the GL pool was also measured using U-14CG. At the end of the I period myocardial GL content was less than 20% of the C value (2.4 vs 13.4 .mu.mol/g w w, p <.001) and after 20, 30 and 50 min of R was 5.3, 7.1 and 10.6 .mu.mol/g w w, respectively. During the first 20 min of R the quantity of exogenous G incorporated into GL was 2.5 times higher than during control (46.0 vs 18.7 nmol of G/min; p < .001). This rate was still elevated after 30 min of R (30 nmol of G/min) but was not significantly different from C after 50 min of R (17.7 nmol of G/min) when 80% of GL had been repleted. The results of this study show that GL synthesis is rapidly activated following a period of acute myocardial ischemia and this is consistent with the hypothesis that the increased FDG uptake in postischemic myocardium of anginal patients mainly traces GL repletion.