FIG. 4, comprising parts A and B, is a diagram and an autoradiogram depicting levels of ACTH and POMC produced in AtT-20 unstimulated or CRF stimulated cells which are transfected with 1 ??g of vector plasmid, pcDNA3 (Invitrogen), or are transfected with 1 ??g of pCMV-TRH, ??BstEII or ??ApaI. In A, the levels of ACTH are shown.