The effect of acute and chronic d-amphetamine treatment on the synthesis, metabolism and turnover of 14C-choline labeled phosphatidylcholine was measured in discrete regions of the rat brain. Chronic d-amphetamine treatment was found to inhibit the turnover of 14C-phosphatidylcholine in the cortex, cerebellum, hypothalamus, diencephalon, brain stem and caudate nucleus. Acute d-amphetamine treatment was found to inhibit the incorporation of 14C-choline into phosphatidylcholine only in the cortex and cerebellum. Studies in vitro suggest that d-amphetamine inhibits cortical phosphatidylcholine synthesis at the cytidine diphosphorylcholine diglyceride transferase step. d-Amphetamine was not found to alter the base-exchange reaction or phospholipase C activity.