To investigate the biological role of Gdown1, we chose mouse liver and generated Gdown1 conditional knockout mice. Differentially expressed genes in Gdown1 KO liver were analyzed by microarrays. Overall design: Gdown1 KO and control (FF) mice were maintained under controlled environmental conditions under a 12-h light /dark cycle and allowed ad libitum access to water and standard laboratory diet. At 8 weeks, mice were sacrificed from 11 am to 1 pm.