The stimulation of prostaglandin production by transforming growth factor-alpha and 12-O-tetradecanoyl-phorbol-13-acetate or 1-oleoyl-2-acetyl-glycerol is synergistic.

Stimulation of prostaglandin production in C-9 rat liver cells by transforming growth factor (TGF)-alpha was synergistic with that of the tumor promoter 12-O-tetradecanoyl-phorbol-13-acetate (TPA). TGF-alpha and TPA synergized the release of radiolabelled compounds from [3H]arachidonic acid prelabelled C-9 cells. 1-Oleoyl-2-acetyl-glycerol (OAG) and TGF-alpha also synergized prostaglandin production in the C-9 cells suggesting that the tumor promoter was mimicking the physiological activator of protein kinase C, 1,2-diacylglycerol. TGF-alpha and TPA also synergistically stimulated arachidonic acid metabolism by NRK-49F rat kidney cells. In A-549 human lung carcinoma cells, TGF-beta, but not TGF-alpha, stimulated arachidonic acid metabolism synergistically with TPA.