PRODUCTION OF ARACHIDONIC-ACID METABOLITES IN ADULT-RAT CARDIAC MYOCYTES, ENDOTHELIAL-CELLS, AND FIBROBLAST-LIKE CELLS

Cells were incubated in the presence of the Ca2+ ionophore A23187 (10 muM) and arachidonic acid (AA, 80 muM). The release of eicosanoids from subcultivated cardiac endothelial and fibroblast-like cells amounted to 23.3 +/- 4.5 and 2.0 +/- 0.4 nmol/mg cellular protein per 30 min, respectively. The release from isolated cardiomyocytes remained below the detection limit of the high-performance liquid chromatography assay (<0.00015 nmol/assay). When a very sensitive radioimmunoassay was applied, cardiomyocytes released 0.002 +/- 0.0001 nmol prostacyclin per milligram cellular protein per 30 min. Prostaglandin (PG) E2 and PGF2alpha, 12-hydroxyheptadecatrienoic acid, 11- and 15-hydroxyeicosatetraenoic acid, and thromboxane B2 were the main eicosanoids released by endothelial cells. The stable product of prostacyclin, 6-keto-PGF1alpha, contributed relatively little to the total amount of eicosanoids formed by endothelial cells. Fibroblast-like cells released predominantly PGE2 and 6-keto-PGF1alpha and, to a lesser extent, 12-hydroxyheptadecatrienoic and 15-hydroxyeicosatetraenoic acids. Neither endothelial cells nor fibroblast-like cells released leukotrienes. A23187 stimulated eicosanoid release from endothelial cells when exogenous AA was below 40 muM. Addition of albumin reduced the amount of eicosanoids produced. Histamine and bradykinin did not influence 6-keto-PGF1alpha and PGE2 production in cardiomyocytes. Histamine only gave rise to a slight but significantly higher release of 6-keto-PGF1alpha in endothelial cells.