Delta 6 desaturase in brain and liver during development and aging.

delta 6 Desaturase was measured in the mouse brain and liver using linoleic acid as substrate. During pre- and postnatal development, delta 6 desaturase in brain decreased dramatically (12-fold) up to postnatal day 21 and remained nearly constant thereafter. In liver, the activity increased approximately 9-fold between day 3 before birth and day 7 after birth. Then it decreased slightly up to weaning and was approximately constant up to 4 mo. From then on, delta 6 desaturase decreased with age (40% between 4 and 17 mo).