Effect of Treatment with Phenformin, Diphenylhydantoin or <i>L</i>-Dòpa on Life Span and Tumour Incidence in C3H/Sn Mice

The chronic treatment of female C3H/Sn mice with phenformin (2 mg/day) and diphenylhydantoin (2 mg/day) prolonged mean life span by 23 and 25%, respectively, and decreased spontaneous tumour incidence by 4.0 and 2.3 times, respectively. The chronic treatment of mice with L-dopa (2 mg/day) did not change these parameters and decreased the multiplicity of mammary tumours. The mechanisms of the drug action on mouse life span and tumour incidence are discussed.