• 作者： 林仁混
• 中文摘要： DAB, MAB與BzoMAB係致肝癌性化合物，AB則屬非致癌性化合物。最近癌學之研究已闡明很多致癌物必在細胞中代謝活化後，才能發揮作用。DAB可經由代謝途徑變為MAB，再變為N-OH-MAB，最後變為N-SO3-O-MAB才是致癌物之活化型。BzoMAB是由化學方法合成的活化型致癌物，其作用與N-SO3-O-MAB同。 本研究結果發現BzoMAB有最強的崎型作用，並最能提高多核?酸磷酸二酯?、鹼性磷酯?及環腺嘌呤?核磷酸二酯?之活性。DAB和MAB也有此等作用，但較為微弱。雖然AB具有最強的雞胚毒殺作用，但其畸型作用甚為微弱，最令人注意者，AB對上述各種?之活性並無影饗。 由於這些致癌物之作用目標在於肝部，因此發現肝部的?受到影響的程度最大。環腺嘌呤?核磷酸二酯?對細胞中cAMP之濃度有調節之作用，該?能受上述致癌物之提高，指出該等致癌物影響分化程序之可能途徑。cAMP已被認為是細胞分化之調節樞紐，因此致癌物可能使該二酯?上升以減少細胞中cAMP之濃度而阻撓細胞之分化，最後導致畸型作用或癌化作用。此種可能性值得進一步的研討。
• 英文摘要： The aminoazo compounds N-methyl-4-aminoazobenzene (MAB), N,N-dimethyl-4-aminoazobenzene(DAB) and N-benzoyloxy-N-methyl-4-aminoazobenzene (Bzo-MAB) are carcinogenic ,to rats whereas 4-aminoazobenzene (AB) is non-carcinogenic. BzoMAB, an excellent synthetic prototype of the metabolized active form of MAB or DAB was shown to be most teratogenic, less embryotoxic and most active in increasing the activities of polynucleotide phosphodiesterase, alkaline phosphatase, and cyclic AMP phosphodiesterase in chick embryo, while MAB and DAB were found to be moderately teratogenic and moderately active in increasing the activities of these enzymes. Although AB is most embryotoxic to the chick embryo, it is less teratogenic and fails to change the activities of these enzymes. Since MAB, DAB and BzoMAB were hepatotoxic and hepatocarcinogenic compounds, the activities of hepatic enzymes were most affected. It is emphasized that the elevation of cyclic AMP phosphodiesterase caused by these carcinogenic compounds will deplete the intracellular level of cyclic AMP and thus interfere with the process of tissue differentiation. The adverse effect of this interference may lead to teratogenesis and/or carcinogenesis.
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