Effect of tryptophan on isolated hepatocytes of rats.
Effect of tryptophan on isolated hepatocytes of rats.
复制标题
色氨酸对大鼠离体肝细胞的影响。
DOI：
10.1007/bf02890234
复制
发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Sidransky,H
中科院分区：
文献类型：
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作者：
Wang,D;Verney,E;Kurl,RN;Sidransky,H
向成年大鼠肝细胞培养物中添加色氨酸可刺激 DNA 合成。与对照培养物相比，用色氨酸处理培养物48小时但也短至6小时，观察到通过3 H-胸苷掺入DNA测量的DNA合成的增加。 30小时时增加也很明显，并且在用色氨酸处理后维持长达48小时。色氨酸导致的 DNA 合成增加不能归因于细胞损伤或 DNA 降解增加。在收获肝细胞后添加的降解酶中，只有DNA酶减少3 H-胸苷的掺入。观察到的效果是色氨酸特异的，因为用犬尿氨酸、异亮氨酸、蛋氨酸或丝氨酸治疗未能显示出显着效果。用羟基脲预处理培养的肝细胞可防止色氨酸刺激的 DNA 合成增加，表明后者是由于复制性而非修复性 DNA 合成所致。添加二乙基亚硝胺进行的实验也暗示了色氨酸在 DNA 复制合成中的作用。讨论了色氨酸诱导DNA 合成的机制。
The addition of tryptophan to adult rat hepatocyte cultures stimulated DNA synthesis. The increase in DNA synthesis as measured by3H-thymidine incorporation into DNA was observed on treatment of the cultures with tryptophan for 48 h but also as short as for 6 h in comparison with control cultures. An increase was also apparent at 30 h which was maintained for up to 48 h post treatment with tryptophan. The increase in DNA synthesis by tryptophan cannot be attributed to cell injury or to increased DNA degradation. Of the degradative enzymes added after harvesting the hepatocytes, only DNase decreased incorporation of3H-thymidine. The observed effect was specific for tryptophan since treatment with kynurenine, isoleucine, methionine or serine failed to show a significant effect. Pretreatment of cultured hepatocytes with hydroxyurea prevented the tryptophan stimulated increase in DNA synthesis suggesting that the latter was due to replicative and not to repairative DNA synthesis. Experiments performed with the addition of diethylnitrosamine also alluded to tryptophan’s role in replicative DNA synthesis. The mechanism of tryptophan-induced DNA synthesis is discussed.