Ishikawa S, Oda T, Sato Y, Mochizuki M
Kyoritsu College of Pharmacy, Tokyo, Japan.
Mutat Res. 1996 Jul 5;368(3-4):261-5. doi: 10.1016/s0165-1218(96)90067-1.
Indenestrol A (IA), one of metabolites of the indanyl group of diethylstilbestrol, has a stronger binding affinity for the estrogen receptor and also a weaker uterotropic activity than endogenous estradiol. We tested the microbial mutagenicity of structural isomers of indenestrol A and indenestrol B (IB) in Salmonella typhimurium TA100 and TA98 and in Escherichia coli WP2 uvrA to investigate whether the interaction of diethylstilbestrol or IA with genomic DNA has any part in their carcinogenicity and other biological activities. In the absence of S9 mix, (+/-)-IA was cytotoxic at higher doses (1 and 10 mumol/plate), and both (+/-)-IA and (+/-)-IB were non-mutagenic at lower doses (0.1-100 nmol/plate). In the presence of S9 mix, (+/-)-IA was cytotoxic at higher doses (0.5 and 1 mumol/plate), and at the other doses, (+/-)-IA and (+/-)-IB did not show any distinct increase in revertants. Although (+/-)-IA and (+/-)-IB showed a slight increase in the revertants in strain TA100 by the preincubation method without S9 mix, these results were considered to be negative, because no reproducible dose-revertants relationship necessary for a chemical to be determined as mutagenic was obtained. The S9 fraction interacted with (+/-)-IA or (+/-)-IB enzymatically or non-enzymatically, and weakened its cytotoxicity, so that the toxic dose was higher in the presence of S9 mix than in its absence. Both the plate incorporation and preincubation methods were used with a wide range of concentrations of (+/-)-IA and (+/-)-IB in the present experiment. No clear positive mutagenic data were obtained. These results are the first reports on the mutation assays of (+/-)-IA and (+/-)-IB, and suggest that they were non-mutagenic towards the bacterial strains tested. The study revealed that the cytotoxic activity of (+/-)-IA and (+/-)-IB did not correlate with DNA interaction, but was the result of a direct effect on microtubule polymerization, although indenestrols are known to have strong binding affinities for estrogen receptors.
茚雌酚A（IA）是己烯雌酚茚满基团的代谢产物之一，对雌激素受体具有更强的结合亲和力，与内源性雌二醇相比，其子宫促生长活性也较弱。我们在鼠伤寒沙门氏菌TA100和TA98以及大肠杆菌WP2 uvrA中测试了茚雌酚A和茚雌酚B（IB）结构异构体的微生物致突变性，以研究己烯雌酚或IA与基因组DNA的相互作用是否在其致癌性和其他生物学活性中起任何作用。在无S9混合液的情况下，（±）-IA在较高剂量（1和10 μmol/平板）时具有细胞毒性，而（±）-IA和（±）-IB在较低剂量（0.1 - 100 nmol/平板）时均无致突变性。在有S9混合液的情况下，（±）-IA在较高剂量（0.5和1 μmol/平板）时具有细胞毒性，在其他剂量下，（±）-IA和（±）-IB的回复突变菌落数没有明显增加。尽管通过无S9混合液的预孵育方法，（±）-IA和（±）-IB在TA100菌株中的回复突变菌落数略有增加，但这些结果被认为是阴性的，因为未获得化学物质被确定为致突变物所需的可重复剂量 - 回复突变关系。S9组分与（±）-IA或（±）-IB发生酶促或非酶促相互作用，并减弱其细胞毒性，因此在有S9混合液时的毒性剂量高于无S9混合液时。在本实验中，平板掺入法和预孵育法均使用了广泛浓度的（±）-IA和（±）-IB。未获得明确的阳性致突变数据。这些结果是关于（±）-IA和（±）-IB突变试验的首次报道，并表明它们对所测试的细菌菌株无致突变性。该研究表明，（±）-IA和（±）-IB的细胞毒性活性与DNA相互作用无关，而是对微管聚合产生直接影响的结果，尽管已知茚雌酚对雌激素受体具有很强的结合亲和力。
