Stability of oleamide in rat serum. [14C]Oleamide (lanes 1 and 2), [14C]N-oleoylglycine (lanes 3 and 4) or [14C]oleic acid (lanes 5 and 6)(80,0000 cpm each) were incubated at room temperature in 50 μL TBS containing 0.5 μL of rat serum for either 0 min (lanes 1,3,5) or 60 min (lanes 2, 4, 6). Samples were first extracted with 5 parts ethyl acetate followed by a second extraction with 5 parts hexane/ethyl acetate 1:2. The organic phases were pooled and dried under a stream of nitrogen. Each sample was dissolved in 10 μL of ethanol and applied to a silica TLC plate. The plate was developed as described under Materials and Methods, and the radioactivity was visualized by phosphorimager.