NR4A1 and neoplasm: More importantly, knocking down orphan nuclear receptor subfamily 4 group A member 1 (Nr4a1) in AtT20 (a mouse pituitary corticotrope tumor cell line) decreased the mRNA and protein of CEB3L1 under both the basal condition and DH condition stimulated with forskolin, further investigation revealed the transcriptional activation of Creb3l1 by Nr4a1 through binding to the NBRE site present in the promoter.