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Studies on metabolisms of radioactive materials and radiosensitivity under zinc deficiency

缺锌条件下放射性物质代谢及放射敏感性研究

基本信息

批准号：
61560333
负责人：
MATSUSAKA Naonori
金额：
$ 1.02万
依托单位：
Iwate University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1988
项目状态：
已结题

项目摘要

Whole-body retentions of radioactive Zn were measured by gamma counting periodically after a single oral administration of the isotope to young and adult mice maintained on a Zn-deficient and Zn-normal diet. The young mice had higher retentions than the adult in both the Zn-deficient and Zn-normal groups Under Zn deficiency, however, greater amount of radioactive Zn was absorbed from the gastrointestinal tract in both age groups. Higher levels of stable Zn in the diet was effective for reducing the body retentions of radioactive Zn.In addition, placental transfer of radioactive Zn was studied inpregnant mice of late gestational stage, supplied a Zn-deficient and Zn-normal diet. After a single oral administration of the isotope to pregnant mice, whole-body retentions were measured until parturition. The wholebody retention values of the Zn-deficient groups remained at higher levels until parturition. An abrupt decrease of the retention values was observed in both Zn-deficient and Zn-normal dams just after parturition: the differences between the values one day before parturition and the values just after pargurition account for the amount of the radioactive Zn incorporated into a litter of offsprings through placenta in utero.Radiosensitivity under Zn deficiency was observed in SPF mice after irradiation of gamma rays (750 rad). Contrary to our expectation, mice of a Zn-deficient group showed lower radiosensitivity than those of a Zn-normal group. The mechanism of this phenomenon is under investigation.

在单次口服同位素后，用伽马计数法定期测量放射性锌的全身保留量，以缺锌和正常锌饮食维持的幼鼠和成年小鼠。无论是缺锌组还是正常锌组，幼鼠在缺锌状态下的固位率均高于成年小鼠，但两个年龄组小鼠胃肠道吸收的放射性锌均高于成年小鼠。饲料中较高水平的稳定锌能有效地减少放射性锌在体内的滞留。此外，还对妊娠晚期小鼠胎盘放射性锌的转运进行了研究，提供了一种缺锌和补锌的饲料。在给怀孕的小鼠口服一次同位素后，测量其全身的保留量，直到分娩。缺锌组的整体保留值一直保持在较高水平，直到分娩。锌缺乏和锌正常的母鼠在分娩后立即观察到存留值的突然下降：分娩前一天的值与分娩后的值之间的差值解释了子代通过宫内胎盘进入一窝后代的放射性锌的量。SPF小鼠在缺锌情况下观察到伽玛射线(750rad)照射后的辐射敏感性。与我们的预期相反，锌缺乏组的小鼠表现出比锌正常组更低的辐射敏感性。这一现象的机制正在调查中。