A recombinant plasmid carrying human transferrin receptor cDNA in reverse orientation downstream from the human cytomegalovirus immediate early promoter/enhancer element was introduced into the HuH-7 human hepatoma cell line by lipofection. Cell surface transferrin binding and iron uptake from transferrin each decreased by about 50% in stable transfectants bearing integrated antisense DNA expression vector. Northern blot analysis indicated that the abundance of target transferrin receptor message was not altered by antisense RNA. These results suggest that the antisense transcript interferes with expression of the endogenous transferrin receptor gene at the level of translation.