passages.id: split_1_test_1039_passage
passages.type: progene_text
passages.text: Arachidonic ( 20:4(n-6 ) ) , eicosapentaenoic ( 20 : 5(n-3 ) ) , and docosahexaenoic ( 22 : 6(n-3 ) ) acids are major components of brain and retina phospholipids , substrates for eicosanoid production , and regulators of nuclear transcription factors .