HETEROGENEOUS FATTY-ACID UPTAKE EARLY AFTER REPERFUSION IN RAT HEARTS

We determined whether spatial distributions of substrate uptake are he terogeneous within the area at risk during reperfusion. Quantitative a utoradiography with imaging plates and two long-lived radioisotopes wa s applied to 15 open-chest, anesthetized rats subjected to 30 min of c oronary artery ligation and 30 min of reperfusion. Regions showing inc reased beta-methyl-[1-C-14]heptadecanoic acid ([C-14]BMHDA) uptake (16 6 +/- 17% of that in the nonischemic area) appeared at the lateral bor ders and subepicardial layer within the area at risk, and 2-deoxy-D-[1 -H-3]glucose ([H-3]DG) uptake was 103 +/- 24% in these regions. Region s with decreased [C-14]BMHDA uptake (28 +/- 11%) occupied the midmyoca rdial layer except at the lateral borders within the area at risk, and [H-3]DG uptake was 62 +/- 18% in these regions. The percentage interr egional coefficient-sof variation (index of heterogeneity) in [C-14]BM HDA uptake, [H-3]DG uptake, and blood flow were higher in the area at risk than in the nonischemic area (76 +/- 23 vs. 21 +/- 7%, 39 +/- 10 vs. 21 +/- 7%, and 49 +/- 19 vs. 14 +/- 4%, respectively). Heterogeneo us distributions of substrate uptake may explain the conflicting resul ts concerning substrate metabolism during reperfusion.