ASSESSMENT OF MUTAGENIC POTENTIAL OF PROPOXUR AND ITS MODULATION BY INDOLE-3-CARBINOL

Propoxur is a widely used dithiocarbamate pesticide. In the present se t of investigations, mutagenicity of propoxur (in formulation) was stu died using the micronucleus assay in bone marrow of Swiss mice. Single intraperitoneal (ip) administration of 25 mg/kg body weight dose of p ropoxur, which is a maximum tolerated dose (MTD), significantly induce d the micronucleus formation in bone marrow cells after a 24- and 48-h r exposure. A half and a quarter of the MTD (12.5 and 6.25 mg/kg) were found ineffective to induce the micronuclei formation after 24- and 4 8-hr time periods by the ip route. However, the PCE:NCE ratio was inhi bited significantly with all the dose levels at both time periods. Ora l administration of propoxur at different dose levels also induced mic ronuclei formation. A single application of 50 and 25 mg/kg dose level s of propoxur, which are MTD and 50% of MTD, also significantly induce d micronuclei formation after 24- and 48-hr time periods in bone marro w cells of Swiss mice as compared with solvent control group, whereas a 12.5 mg/kg dose of propoxur was ineffective in inducing micronuclei formation. Single application of indole-3-carbinol (I3C), a glucobrass icin derivative present in cruciferous vegetables, significantly inhib ited the propoxur-induced micronuclei formation when it was given at t he dose level of 500 mg/kg body weight 48 hr before the single applica tion of propoxur. Therefore, it seems that propoxur is mutagenic in th e above test systems and I3C inhibited the mutagenicity of propoxur si gnificantly. (C) 1997 Elsevier Science Ltd. All rights reserved.