Induction of PGAR expression during adipocyte differentiation. 3T3-L1 preadipocytes were cultured to confluence and induced to differentiate using established protocols, i.e., 3 days of dexamethasone-isobutylmethylxanthine-insulin treatment followed by insulin treatment. Northern analysis was performed on the total RNA isolated 3, 6, 9, and 12 days after induction (10 μg/lane).