Synergistic deleterious effects of nitrous oxide exposure and vitamin B12 deficiency

Rats raised on a vitamin B12-deficient or -sufficient diet were either exposed or not exposed to nitrous oxide for 3 hours before sacrifice. Bone marrow cells were assayed for thymidylate synthetase activity by the deoxyuridine suppression test. A synergistic interaction between vitamin B12 deficiency and nitrous oxide exposure was observed.