Effect of pesticides on scheduled and unscheduled DNA synthesis of rat thymocytes and human lymphocytes.

The action of seventeen pesticides (insecticides, fungicides and herbicides) has been studied with short-term in vitro system using rat thymocytes and/or human lymphocytes. The parameters studied were: a)the action of chemicals tested in scalar doses on DNA synthesis of rat thymocytes; b)damage exerted by pesticides on human lymphocyte DNA measured as unscheduled DNA sythesis; c)the interference of chemicals tested with human lymphocyte repair capability after damage exerted on cells by ultraviolet rays. The results obtained suggest that some of tested pesticides don't induce damages to human lymphocyte DNA, some others elicit low DNA repair if compared to the repair following a standard ultraviolet irradiation and some of them (6/17) exert a marked inhibition of cell repair processes after ultraviolet irradiation. Data are discussed on the basis of a possible role played by these substances as carcinogenic agents in the environment.