Dietary ethanol reduces phosphatidylcholine levels and inhibits the uptake of dietary choline in Drosophila melanogaster larvae

1. 1. Low to moderate concentrations of dietary ethanol (200 mM to 600 mM) significantly increased the level of phosphatidylethanolamine (PE), while phosphatidylcholine (PC) levels decreased in third instar larvae. This was seen in both ethanol tolerant and intolerant strains of Drosophila melanogaster, indicating that the reduction of PC is not associated with a high level of ethanol tolerance. 2. 2. The phospholipid changes were not ethanol-specific. Larvae fed ethanol, n-butanol, isopropanol, methanol, and n-propanol exhibited similar changes. 3. 3. At 200 mM concentrations, dietary ethanol acted as a competitive inhibitor for the larval uptake of dietary choline. At higher concentrations, dietary ethanol acted as a noncompetitive inhibitor. This ethanol-induced inhibition of dietary choline uptake can only partially explain the ethanol-induced reductions in larval PC.