Developmental Profiles of Lipogenic Enzymes and Their Regulators in the Neonatal Mouse Brain

It has been shown that lipogenic enzymes, such as fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC), are highly expressed in the rodent brain during the early neonatal period and decline thereafter. However, cellular localization of these enzymes is unknown. Presently, we examined developmental changes in the levels and cellular localization of FAS and ACC, and their putative regulators, sterol-regulatory element-binding protein (SREBP)-1 and AMP-activated protein kinase (AMPK) in the mouse brain. Levels of these proteins including phosphorylated forms of ACC and AMPK decreased between postnatal day 4 (P4) and P19. Immunohistochemical studies indicated that FAS, ACC, AMPK, and SREBP-1 were expressed in neurons at P7, while FAS was found mostly in cells of oligodendrocyte lineage at P19. These studies suggest that neurons in the early neonatal brain are involved in do novo fatty acid synthesis.