[Effect of buformin and diphenylhydantoin on the life span, estrous function and spontaneous tumor incidence in rats].

Chronic treatment of female rats with buformin (k mg/day per rat) is shown to decrease the body weight, to increase the average life span by 9% and to reduce the incidence of spontaneous tumors. The administration of diphenylhydantoin (7.5 mg/day per rat) would not change these parameters. The treatment of rats with buformin and diphenylhydantoin was also found to prolong their reproductive period and to reinitiate regular estrous cycles in persistent estrous rats.