Study on the mechanisms of vitamin A-storage in arctic animals

北极动物维生素A储存机制的研究

基本信息

批准号：
11694238
负责人：
SENOO Haruki
金额：
$ 5.63万
依托单位：
Akita University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11694238/
关键词：
Arctic vitamin A Svalbard stellate cells polar bear Arctic fox reinyl ester liver 北極圏動物肝臓星細胞ホッキョクグマレチノール血清

项目摘要

As xenobiotics may reduce the threshold of vitamin A-toxicity and both vitamin A and fatsoluble xenobiotics have a tendency to accumulate in the food chain, we have perfomied a systematic characterization of the hepatic vitamin A-storage in mammals and birds of the Svalbard archipelago and searched for sign of vitamin A-related toxicity in these animals. The top predators including polar bear, arctic fox, bearded seal and glaucous gull contained about 10-20 times more vitamin A than all other arctic animals studied as well as their genetically related continental top predators. The values are also high compared to normal human and experimental animals like mouse and rat. This massive amount of hepatic vitamin A was located in large autofluorescent lipid droplets in hepatic stellate cells. The droplets made up most of the cells' cytoplasm. The development of such an efficient vitamin A-storing mechanism in the hepatic stellate cells may have contributed to the survival of top predators in the extreme environment of the Arctic. These animals demonstrated neither sign of hypervitaminosis A nor pathological findings in the liver.Kidney total retinol, which may be used as a biomarke for vitamin A-related toxicity or excess, in polar bear and bearded seal were below 1% of their liver value, Which is in the normal range for most animals. Arctic fox and glaucous gull, however, had kidney levels of about 9 and 42% of the liver values, respectively. This increased kidney concentrations of total retinol in arctic fox and glaucous gull is most likely a sign of vitamin A-toxicity that deserved attention. This observation is alarming and has not been observed previously in free-living animals. Analysis of samples from older predators who over time may have accumulated more of vitamin A and organic pollutants may clarify whether these and other signs of vitamin Atoxicity is present in such animals.

As xenobiotics may reduce the threshold of vitamin A-toxicity and both vitamin A and fatsoluble xenobiotics have a tendency to accumulate in the food chain, we have perfomied a systematic characterization of the hepatic vitamin A-storage in mammals and birds of the Svalbard archipelago and searched for sign of vitamin A-related toxicity in these animals.顶部的捕食者包括北极熊，北极狐狸，胡须密封和魅力的海鸥，其维生素A的维生素A的含量比所研究的所有其他北极动物及其遗传相关的大陆顶部捕食者高约10-20倍。与正常的人和实验动物（如小鼠和大鼠）相比，这些值也很高。这种大量的肝维生素A位于肝星状细胞中的大型自动荧光脂质液滴中。液滴构成了大多数细胞的细胞质。在肝星状细胞中这种有效的维生素A储存机制的发展可能导致了北极极端环境中顶级捕食者的存活。这些动物在肝脏中既没有表现出高vitaminiso的迹象，也没有病理性发现。Kidney总视黄醇，可以用作北极熊和胡须密封中的维生素A与维生素A的毒性或过量的生物摩骨，低于其肝脏值的1％，这在大多数动物的正常范围内是正常范围的。然而，北极狐狸和青光海鸥的肾脏水平分别为肝脏值的9％和42％。北极狐狸和青光海鸥中总视黄醇的肾脏浓度提高，很可能是维生素A毒性的迹象，值得关注。该观察结果令人震惊，并且在自由活动的动物中尚未观察到。分析随着时间的推移积累更多的维生素A和有机污染物的样品，可能会阐明这些动物中是否存在这些维生素毒素的迹象。