OVER-EXPRESSION OF PROTEIN-KINASE C-ALPHA ENHANCES PLATELET-DERIVED GROWTH FACTOR-INDUCED AND PHORBOL ESTER-INDUCED BUT NOT CALCIUM IONOPHORE-INDUCED FORMATION OF PROSTAGLANDINS IN NIH 3T3 FIBROBLASTS

Over-expression of human protein kinase C-alpha in murine NIH 3T3 fibr oblasts is associated with an increased platelet-derived growth factor - and phorbol ester-mediated formation of prostaglandins, whereas the calcium ionophore-induced release of arachidonic acid metabolites is u naffected; however, the differences of arachidonic acid and prostaglan din formation are much more pronounced with platelet-derived growth fa ctor than with phorbol ester. Platelet-derived growth factor induces a n identical elevation of intracellular free calcium in control and pro tein kinase C-alpha over-expressing cells; the phorbol ester has no ef fect on intracellular free calcium in both cell lines. These results d emonstrate that protein kinase C-alpha may couple to arachidonic acid cascade in NIH 3T3 fibroblasts.