Induction of haem synthesis in Hep G2 human hepatoma cells by dimethyl sulphoxide. A transcriptionally activated event.

Exposure of cultured human hepatoma cells (Hep G2) to medium containing 2% (v/v) dimethyl sulphoxide resulted in an approximate doubling in the activity of delta-aminolaevulinate dehydratase, an increase in the haem content and a decreased growth rate; induced enzyme activity was decrease by 50% after treatment with alpha-amanitin. The findings are strikingly similar to those seen in murine Friend-virus-transformed erythroleukaemia cells.