Mutagenic activity of ascorbate in mammalian cell cultures

Exposure of Chinese hamster ovary (CHO) cells to solutions of ascorbate (2--5 x 10(-4) M) resulted in the induction of somatic mutations at the hypoxanthineguanine phosphoribosyl transferase (HGPRT) locus. Mutant cells were resistant to 6-thioguanine (10 microgram/ml) and sensitive to HAT (hypoxanthine, aminopterin, thymidine) medium. Doses of ascorbate which were mutagenic were also toxic. Addition of catalase to such ascorbate concentrations prevented both mutagenesis and toxicity. This suggests that mutagenic metabolites of ascorbate may involve peroxide radicals.