An in vitro model of acetaldehyde metabolism by rodent conceptuses

A culture model is described for the study of acetaldehyde (AcH) metabolism by explanted postimplantation rat and mouse conceptuses. The ability of 12-d rat and 10-d mouse embryos to metabolise AcH was demonstrated. The elimination rate for the 12-d rat conceptus using an initial AcH concentration of 1 mM in the medium was found to be 1.8 nmol/mg per minute. When the conceptus was divided into embryonic and extraembryonic tissue, the rates were 1.6 and 2.2 nmol/mg per minute, respectively. When the AcH concentration was reduced to 50 microM the rate was 0.095 nmol/mg per minute. The results provide further evidence for a functional barrier that prevents AcH entry to the embryo. A comparative experiment using CBA/beige mouse conceptuses showed that AcH elimination characteristics may be qualitatively similar to those in rat embryos, but that the estimated elimination rate of 0.8 nmol/mg per minute was less than half that of the rat. Thus the "metabolic barrier" may be less efficient in the mouse. This may be important in view of the greater sensitivity of the mouse to ethanol embryotoxicity.