12-hydroxy-5Z, 8Z, 10E, 14Z, eicosatetraenoic acid (12-HETE) stimulates cAMP production in normal human fibroblasts.
We report here that the 12-lipoxygenase metabolite of arachidonic acid, 12-hydroxy-5Z, 8Z, 10E, 14Z, eicosatetraenoic acid (12-HETE), stimulates cAMP production in human fibroblasts among various cultured cell lines tested. Although 12-HETE seemed to stimulate the phospholipase C (PLC)-protein kinase C (PKC) system, inhibitors against PLC and PKC did not reduce the cAMP production induced by 12-HETE, indicating that the activation of PLC-PKC system is not positively coupled with the stimulation of cAMP production. On the other hand, the cAMP production induced by 12-HETE was dependent on the Ca2+/calmodulin system in the cells. The results suggest that 12-HETE specifically stimulates Ca2+/calmodulin-dependent adenylyl cyclase to increase cAMP level in the fibroblasts.