title: The effects of several croton oil constituents on two types of DNA repair and cyclic nucleotide levels in mammalian cells in vitro.
abstract: The purpose of the present study was to determine the effects of two potent tumor-promoting agents on two DNA repair mechanisms and cyclic nucleotide levels in mammalian cells. Human amnion (AV3) cells were treated with low dose levels of either UV of N-acetoxy-acetylaminofluorene. Subsequently, DNA excision repair as measured by unscheduled DNA synthesis was followed in the absence or presence of non-toxic levels of either 12-O-tetradecanoylphorbol-13-acetate (TPA), phorbol-12,13-dibenzoate (PDB), both potent tumor promoters, or phorbol, a non-promoter. Neither of these compounds inhibited DNA repair synthesis occurring in response to low doses of the carcinogenic agents. In addition, TPA did not inhibit "post-replication repair" in response to UV irradiation of growing Chinese hamster (V79-4) cells. However, both TPA and PDB did cause rapid dramatic increases in cyclic guanosine monophosphate levels in human amnion cells; phorbol had no effect. Neither of these compounds affected cyclic adenosine monophosphate levels. These results are discussed in the light of a possible mechanism of the action of tumor promoters involving "post-replication repair".
mesh_terms: D000099:Acetoxyacetylaminofluorene / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D002499:Centrifugation, Density Gradient; D006224:Cricetinae; D003436:Croton Oil / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism*; D004260:DNA Repair / Q000187:drug effects*; D004261:DNA Replication / Q000187:drug effects* / Q000528:radiation effects; D006801:Humans; D008858:Microscopy, Phase-Contrast; D010703:Phorbol Esters / Q000494:pharmacology; D010704:Phorbols / Q000494:pharmacology; D014466:Ultraviolet Rays
chemical_list: D010703:Phorbol Esters; D010704:Phorbols; D000099:Acetoxyacetylaminofluorene; D003436:Croton Oil; D000242:Cyclic AMP; D006152:Cyclic GMP