N-Docosahexaenoylethanolamine (synaptamide): Carbon-14 radiolabeling and metabolic studies.

•DHA-ethanolamine (synaptamide) was radiolabeled with carbon-14 in both the ethanolamine and DHA moieties.•Brain uptake of intravenous DHA-ethanolamine in mice was greater than for labeled DHA.•Both isotopomers of radiolabeled synaptamide produced radiolabeled phospholipids in mouse brain.•PF3845, a specific inhibitor of fatty acid amide hydrolase (FAAH), eliminated formation of labeled phospholipids.