Uptake and elimination of ethanol by young zebrafish embryos

Among animal models being explored to understand ethanol-induced teratogenesis, the zebrafish (Danio rerio) is attracting attention because its embryonic development is well characterized and readily visualized. Despite the potential of the zebrafish embryo in research on developmental anomalies produced by ethanol exposure, little is known about the relationship between embryonic ethanol content and the nature/severity of ethanol-mediated deficits. Here, using gas chromatography and radiometry of labeled ethanol carbon, we examine accumulation and clearance of ethanol by dechorionated zebrafish embryos during blastulation/gastrulation. Our data indicate that: (a) rates of uptake and loss of ethanol are directly proportional to the extra-/intra-embryonic ethanol concentration gradient and (b) ethanol in the water fraction of embryos reaches near equimolarity with ethanol in the exposure medium. It appears that, within a wide range of exposure concentrations, embryonic ethanol content can be predicted accurately according to exposure time. Furthermore, it appears that embryonic ethanol can be adjusted rapidly to and maintained at a targeted concentration.