Metabolism of fibroblasts plays a key role in wound healing, fibrosis, rheumatoid arthritis, and similar physiological and pathological processes. The regulatory influence of eicosanoids, an important class of inflammatory mediators, on fibroblast metabolism, in these processes is, to date, unclear. The aim of this study was to investigate the effect of some eicosanoids on chemotaxis and protein synthesis of fibroblasts in vitro. Of twelve eicosanoids tested, only 5(S)-HETE, LTB4, and 12(S)-HETE were active as chemo-attractants for fibroblasts. 5(S)-HETE was the most potent attractant. It exerted its maximal activity at 10(-10) mol/l. 12(S)-HETE and LTB4 caused similar dose dependent fibroblast chemotaxis with a maximum of activity at 10(-7) M and 5 x 10(-8) M, respectively. Hydroxylation of LTB4 on C20 or methylation of the carboxy group of 12(S)-HETE decreased reactivity of the parent compounds only slightly. Eicosanoid induced chemotaxis could be antagonized by 12(S)-HETE but not by the proteinaceous chemoattractants fibronectin, PDGF, or EGF. Receptors for peptide and eicosanoid mediated chemotaxis are thus different. Inhibition of collagen synthesis was observed in the presence of 5(S)-HETE and 12(S)-HETE while total protein synthesis was unaffected by 12(S)-HETE and augmented by 5(S)-HETE. These data suggest that certain eicosanoids specifically regulate fibroblast activities in wound healing and similar events of connective tissue reorganization.