Effects of lipid peroxidation, Ca2+ and adrenalin on the release of fatty acids from rabbit kidney cortex slices

Ascorbic acid (1 mM) plus Fe2+ (0.4 mM) and Ca2+ (4 mM) stimulated the release of arachidonic acid from rabbit kidney cortical slices. The release of arachidonic acid was inhibited completely by the addition of mepacrine (1.6 mM). Adrenalin (0.8 mM) enhanced the release of individual free fatty acids (C16:0, C18:0, C18:1, C18:2 and C20:4). The release of fatty acids by adrenalin was not inhibited by mepacrine (1.6 mM), but was inhibited by p-chloromercuribenzoic acid (2 mM). These results suggest that the lipolytic process in kidney cortex may be mediated either through the activation of phospholipase A2 by Ca2+ and ascorbic acid plus Fe2+ or through an adrenalin-activated lipase system.