SG-75 induction of increased coronary outflow and PGE1 from ischemic areas in dogs with experimental myocardial infarction.

We measured the coronary blood flow and concentrations of prostaglandin E1(PGE1), PGF2 alpha, and lactate from the ischemic myocardium of dogs treated with either SG-75 or indomethacin. There was a significant increase of coronary blood outflow from the ischemic myocardium after ligation in dogs given SG-75 and in control dogs compared with indomethacin-treated dogs. The release of lactate from the ischemic myocardium decreased significantly in dogs with SG-75 compared with the indomethacin and control group. The concentration of PGE1 rose significantly after ligation in dogs with SG-75 compared indomethacin-treated and those in control dogs. A significant release of PGE1 from the ischemic area of the myocardium treated with SG-75 was clearly demonstrated at 60 min after ligation of the LAD coronary artery. Also, a significant release of PGF2 alpha from the ischemic area of the myocardium was demonstrated at 15 min after ligation. There was a significant correlation between the increase of coronary outflow and PGE1 release from the ischemic myocardium ( 4= 0.70, p less than 0.01). However, no significant correlation was demonstrated between the increase of coronary outflow and PGF2 alpha. These results show a close relation ship between increased coronary outflow induced by SG-75 and increased release of PGE1. Thus, a beneficial effect of SG-75 on the ischemic myocardium was demonstrated.