Table 5. Overall distribution of phosphatidylethanolamine subclasses in relation to age and diet in rat brain.

	Composition, % of total molecular species
Subclass	YR	YR + FO	OR	OR + FO
		X/22:6
Diacyl	37.34	41.73	32.93	38.38
Alkylacyl	23.78	11.01	16.82	29.52
Alkenylacyl	25.89	27.53	24.83	26.08
		X/20:4
Diacyl	29.34	22.18	29.23	25.38
Alkylacyl	13.58	19.00	19.37	14.94
Alkenylacyl	17.29	17.11	18.83	14.34

X, 18:1 + 16:0 + 18:0; YR, young rats; OR, old rats; FO, fish oil.