Substances that act on living organisms to cause malformations in fetuses and newborns are called teratogens or teratogens. The mechanisms by which malformations manifest are thought to include gene mutations, chromosomal abnormalities, nucleic acid metabolic abnormalities, cell membrane abnormalities, enzyme inhibition or deficiencies, and nutritional or energy deficiencies. It is believed that these changes lead to cell death and disorders of intracellular metabolism and morphological differentiation, which then lead to malformations. Therefore, if damage is caused to the male sperm, even if the female egg is healthy, it is theoretically possible that a malformed child will be born if fertilization occurs. However, in reality, teratogens become a problem when various substances act on the mother's body after pregnancy is established, resulting in malformations. Source: Heibonsha World Encyclopedia, 2nd Edition Information |
生体に作用して胎児や新生児に奇形を発生させる物質を催奇形性物質または催奇性物質という。奇形が発現する機序については,遺伝子突然変異,染色体異常,核酸代謝異常,細胞膜異常,酵素の阻害や欠損,栄養やエネルギーの欠乏などが考えられ,このような変化に伴って細胞の死亡,細胞内の代謝や形態的分化の障害が起こり,奇形につながるものと考えられている。したがって男性側の精子に障害が起こされた場合に,女性側の卵子が健常な場合でも,受精が成立するときは奇形児が生まれることも理論上ありうるが,現実に催奇形性物質が問題となるのは,妊娠が成立してから各種の物質が母体に作用した結果奇形を発生する場合である。
出典 株式会社平凡社世界大百科事典 第2版について 情報 |
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