Insulin promotes LTP in mice by switching the energy substrate preference of astrocytes to fatty acids [Mus]

A total of 46,202 transcripts were detected from RNA extracts from Mus musculus hippocampus. Genes were filtered by setting the minimum FPKM value to log2, followed by a parametric statistical test to identify differentially expressed genes. Within 15 min of insulin administration, 181 transcripts were upregulated and 55 were downregulated. At this early time-point, genes with altered expression were almost exclusively related to neuronal functions. Within 1h following insulin treatment, a similar number of transcripts (173) were upregulated and the expression of three-fold more genes (140) were downregulated. At this time-point, 12 genes associated with the release of lipids and fatty acids were increased. Within 6h following intranasal insulin administration, the number of transcripts with elevated expression remained similar (164), but the number of genes with reduced expression declined to 77. At this time point the genes with elevated expression were largely relate to lipid metabolism. These data demonstrate that insulin delivered directly to the brain produces a rapid, robust, and time-dependent modification in gene expression related to lipid metabolism.