To assess the developmental toxicity of selected glycol ethers and their metabolites, Drosophila melanogaster larvae were reared on media containing equimolar concentrations of 2ME or its acid metabolite MAA (both documented mammalian developmental toxicants), or its acetaldehyde metabolite MALD. Drosophila were exposed throughout development (egg through third instar larvae) to 0.085 mM, 0.17 mM or 0.34 mM of each chemical in culture vials, with each vial containing 1 g of powdered medium and 5 ml of distilled water or a solution of test chemical in water. The highest concentration corresponded to 26 mM/vial of 2ME, a concentration previously shown in our laboratory to increase the incidence of bent humeral bristles in developing flies. A mated, untreated, Oregon-R wild-type female (Mid-American Drosophila Stock Center) was added to each culture vial and allowed to oviposit for 20 hours, then removed. Emerging adults, collected over 10 days, were examined microscopically (25x) for bent humeral bristles or wing blade notches morphological endpoints shown to occur with an increased incidence in flies exposed to developmental toxicants. All chemical treatments statistically increased the incidence of bent bristles compared to concurrent controls (chi-square). The percentage of flies with bent humeral bristles observed with each chemical and at each concentration were: 2ME, 4.1, 9.0 and 11.1 %; MAA, 7.7, 7.0 and 12.5%; MALD, 8.8, 6.9 and 15.3%. No bristle defects were seen in controls (n = 242). These results indicate that exposure to 2ME or its aldehyde or acid metabolites can induce defects in developing flies and support further utilization of this Drosophila-based assay as a pre-screen in developmental toxicology studies.
The Toxicologist. Society of Toxicology 34th Annual Meeting, March 5-9,1995, Baltimore, Maryland