Activation of bile salt dependent lipase by (lyso)phosphatidic acid and platelet activating factor

•BSDL is suspected to play an important extra-intestinal function.•Several possible BSDL effectors were tested using three different substrates.•Physiological concentrations of (lyso)phosphatidic acid and platelet activating factor strongly stimulate BSDL.•PA, LPA and PAF are likely modulators of extra-intestinal activity of BSDL.•Kinetic data suggest the existence of specific binding sites for these effectors. The activity of breast milk BSDL was assayed with or without phospholipids as extra-intestinal effector candidates. Phosphatidic acid, lysophosphatidic acid and platelet activating factor but not phosphatidylcholine and lysophosphatidylcholine stimulated BSDL activity at least as efficiently as taurocholate. The apparent dissociation constants of PA and LPA at saturating concentrations of three different substrates were between 0.1 and 13.4μM and that of PAF was below or equal to 200pM. Kinetic data suggested the existence of at least one binding site for each of these effectors. PA, LPA and PAF are likely extra-intestinal modulators of BSDL activity.