Thyroid Hormone Action in the Adult Brain: Gene Expression Profiling of the Effects of Single and Multiple Doses of Triiodo-L-Thyronine in the Rat Striatum

Thyroid hormones have profound effects onmood and behav-ior, but the molecular basis of thyroid hormone action in the adult brain is relatively unknown. In particular, few thyroid hormone-dependent genes have been identified in the adult brain despite extensive work carried out on the developing brain. In this work we performed global analysis of gene ex-pression in the adult rat striatum in search for genomic changes taking place after administration of T3 to hypothy-roid rats. The hormone was administered in two different schedules: 1) a single, large dose of 25g per 100 g bodyweight (SD) or 2) 1.5 g per 100 g body weight once daily for 5 d (RD). Twenty-four hours after the single or last of multiple doses, gene expression in the striatum was analyzed using Codelink microarrays. SD caused up-regulation of 149 genes and down-regulation of 88 genes. RD caused up-regulation of 18 gene