title: The neuroblast of the grasshopper embryo as a new mutagen test system. III. Chromosome breakage induced by cyclophosphamide is greater with activation by rat hepatocytes than by S12 mix.
abstract: The promutagen cyclophosphamide (CPhos) induces chromosome breaks in neuroblasts of the 14-day-old grasshopper embryo (Chortophaga viridifasciata DeGeer, Orthoptera: Acrididae) only when activated with S12 mix or freshly isolated hepatocytes. After 1-h exposure followed by 3-h recovery, CPhos + hepatocytes (from uninduced adult rats) induces about 5 times more acentric fragments and induces them at lower doses than does CPhos + S12 mix (from phenobarbital-induced rats). Both activation systems contained equivalent amounts of microsomal protein. Hepatocytes could be used in suspension immediately after isolation, thereby obviating the delay necessitated by allowing for attachment. In the absence of CPhos, with or without activators, no chromosome aberrations were observed. Without CPhos, hepatocytes are less toxic than is S12 mix, as determined by reduction in the number of dividing neuroblasts.
mesh_terms: D000818:Animals; D001711:Biotransformation; D002869:Chromosome Aberrations; D003520:Cyclophosphamide / Q000633:toxicity*; D006110:Grasshoppers / Q000235:genetics*; D066298:In Vitro Techniques; D007814:Larva; D008099:Liver / Q000378:metabolism*; D008297:Male; D009152:Mutagenicity Tests / Q000379:methods*; D051381:Rats; D011919:Rats, Inbred Strains; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: D003520:Cyclophosphamide