A stably transfected CHO cell line (LUCLEAD) was used where the coding region of native Firefly luciferase was linked to the 3′-UTR of the bovine growth hormone, and the 5′-nucleotides coding for the albumin signal peptide were linked to the N-terminal end of the luciferase coding region. Incubation of cells with 1 or 2mM sodium butyrate (SB) for 72h had no effect on cell growth since cultures reached confluency at the same time as control cells. Although cell cultures incubated with SB at a concentration of 4mM were only about 60% confluent the luciferase content was about 5-fold higher than that in control cells. Cells incubated with either 1 or 2mM SB showed intermediate levels of luciferase content. The amount of the chaperone BiP in the cells was not affected by incubation with SB. The results indicate that SB can be used to effectively promote synthesis of recombinant luciferase.