- 著者
- Satoru Oshiro Masahiro Kawahara Shirao Mika Kazuyo Muramoto Kazuo Kobayashi Ryuta Ishige Koji Nozawa Makoto Hori Cai Yung Shigetaka Kitajima Yoichiro Kuroda
- 出版者
- The Japanese Biochemical Society
- 雑誌
- The Journal of Biochemistry (ISSN:0021924X)
- 巻号頁・発行日
- vol.123, no.1, pp.42-46, 1998 (Released:2008-11-18)
- 参考文献数
- 27
We previously demonstrated that cultured human fibroblasts internalize iron via transferrin-independent iron uptake (Tf-IU), redox, and receptor-mediated endocytosis uptake systems [Oshiro, S., Nakajima, H., Markello, T., Krasnewich, D., Bernardini, I., and Gahl, W. A. (1993) J. Biol. Chem. 268, 21586-21591]. Of these iron transport systems, the Tf-IU system is involved in the accumulation of transition metals in various mammalian cells. It is also known that in experimental animals fed aluminum (Al), Al at micromolar level selectively accumulates in the brain. In the present study, we examined the effects of Al accumulated in the brain cells on iron transport by the Tf-IU system and iron metabolism, using primary cultures from fetal rat cerebral cortex. Pretreatment of cells with 200 μM Al-nitrilotriacetate upregulated the Tf-IU system for iron. Moreover, of various metals tested, Al markedly upregulated the Tf-IU activity. To examine the influence of Al on iron metabolism, the interaction between Al accumulated in the cells and iron-responsive element binding protein (IRE-BP), a cellular iron regulator, was examined by Northern blot analysis, and activity assay: Al decreased the Tf receptor mRNA level and increased the aconitase activity of IRE-BP. The increase of aconitase activity by Al was also observed in vitro. These results suggest that Al accumulated in cortical cells affects iron metabolism.