Development of Assay Based on Effects of PGBx on the Isolated Perfused Rat Heart.

摘要

PGB(x), a polymeric base-catalyzed derivative of 9,15-diketoprostaglandin B, at high concentrations (equal to or greater than 500 ng/ml) depressed isometric systolic tension and coronary flow and decreased tissue concentrations of ATP and creatine phosphate. At 1000 ng/ml, PGB(x) produced similar effects, but in addition, it markedly enhanced cardiac glycogen utilization, increased tissue concentrations of glucose-l-phosphate and glucose-6-phosphate and caused a significant increase in diastolic tension after being perfused for 60 minutes at this concentration. In well-oxygenated perfused rat hearts, PGB(x) had no effect on disophenol induced alterations in spontaneous heart rate, but did appear to prevent the increase in coronary flow caused by disophenol. Isometric systolic tension decreased significantly in PGB(x)-disophenol treated hearts but not in those receiving disophenol alone. Diastolic tension was increased in hearts which received PGB(x) and disophenol simultaneously. Disophenol caused alterations in glycogen and adenine nucleotide concentrations which were uninfluenced by PGB(x). The amount of ADP in the tissue, however, was lower in those hearts which received both PGB(x) and disophenol. Phosphorylase activity and the lactate present in coronary effluent was the same in both groups.