In vitro binding of the carcinogen N-[methyl-^<14>C]-nitrosodimethylamine by algal dietary fibers and their role in reducing its bioaccumulation.

致癌物N-[甲基-14C]-亚硝基二甲胺与藻类膳食纤维的体外结合及其在减少其生物累积中的作用。

基本信息

批准号：
04671397
负责人：
YAMAMOTO Ichiro
金额：
$ 1.34万
依托单位：
Kitasato University School of Hygienic Sciences
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

The first study was initiated to determine if algal dietary fibers (DF) bind the carcinogen N-[methyl-^<14>C]-nitrosodimethylamine ([^<14>C]-DMNA) in vitro and how bioaccumulation of orally-given carcinogen is affected by a diet containing algal DF.Eight kineds of algal DF, including powdered fronds of Laminaria religiosa (LRP) and agar (from Gracilaria verrucosa) were used in the in vitro test. Cellulose powder (CP) was used as a control DF.In vitro binding rates of DMNA by CP, LRP and agar were 0.28%, 0.65% and 0.21% of the initial dose, respectively. Rats fed a diet containing 2% LRP or 2% agar were examined at 3 h or 24 h after dosing. There was reduced retention of the orally-ingested DMNA in the liver, posibly because of reduced DMNA-adsorption from the intestinal tract earlier than 3 h after dosing. Binding rates of DMNA by algae were neither related to the DF values nor to the extent of reduction of DMNA-absorption from the intestinal tract.The second study was performed to verify the effects of cellulose (nsoluble in water) and of polydextrose (soluble in water), in reducing bioaccumulation of the carcinogen [^<14>C]-DMNA in the same in vivo experimental system, using mice. As the results, [^<14>C]-bioaccumelation in CP-fed mice remarkably reduced at 1 h after dosing, compared with that in control mice.In the time points later than 1 h after dosing, difference in the bioaccumulation between CP-fed mice and cntrols were decreased sowly as the time lapsed. The results suggest that absorption and metabolism of the carcinogen took lace within 1 h after dosing. As to polydextrosefed mice, there was no significant reductin of [^<14>C] uptake, except blood at 24 h after dosing.

开始了第一项研究是为了确定藻类饮食纤维（DF）是否结合了致癌物N- [甲基 - ^<14> c] - 硝基二甲基胺（[^^<14> C] -DMNA）在体外以及如何影响口服癌的生物积累的饮食中，含有饮食的饮食含量为Algal df.eights dff。在体外测试中，使用了Laminaria Religiosa（LRP）和琼脂（来自Gracilaria verrucosa）。纤维素粉末（CP）用作对照DF。通过CP，LRP和琼脂的DMNA的体外结合速率分别为初始剂量的0.28％，0.65％和0.21％。给药后3小时或24小时检查喂食含有2％LRP或2％琼脂的大鼠。肝脏中口服的DMNA的保留降低，这是由于给药后早于3小时的肠道降低的DMNA吸附。藻类通过藻类的DMNA的结合速率既不与DF值相关，也没有与肠道中DMNA吸收吸收的降低的程度。系统，使用鼠标。作为结果，与对照小鼠相比，在给对照小鼠中，在剂量后1小时，在CP喂养小鼠中的[^<14> c] - bioAccumelation。结果表明，致癌的吸收和代谢在给药后1小时内采用花边。关于多脱粉的小鼠，除了给药后24小时，除了血液外，没有显着还原蛋白[^<14> c]的摄取。