Biological and Pharmaceutical Bulletin
Online ISSN : 1347-5215
Print ISSN : 0918-6158
ISSN-L : 0918-6158
Regular Articles
Induction of Hepatic Metallothionein by Trivalent Cerium: Role of Interleukin 6
Kazuo KobayashiRumi ShidaTatsuya HasegawaMasahiko SatohYoshiyuki SekoChiharu TohyamaJunji KurodaNobuo ShibataNobumasa ImuraSeiichiro Himeno
ジャーナル フリー

2005 年 28 巻 10 号 p. 1859-1863


Metallothionein (MT) is a small sulfydryl-rich protein that binds to and is inducible by heavy metals such as mercury, cadmium, zinc, and copper. However, little is known about the induction of MT by trivalent metals except for bismuth. In this study, we examined the induction of MT synthesis by cerium, a trivalent lanthanoid metal. Administration of cerium chloride (CeCl3) to mice resulted in accumulation of cerium and induction of MT in the liver in a dose-dependent manner. Distribution profiles of metals in the soluble fraction of the liver of CeCl3-treated mice analyzed by high performance liquid chromatography/inductively coupled argon plasma-mass spectrometry (HPLC/ICP-MS) demonstrated that the metal bound to MT-I and MT-II was zinc, but not cerium. Administration of CeCl3 caused increases in the activities of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and the levels of serum amyloid A (SAA), an acute phase protein. Among inflammatory cytokines examined, interleukin 6 (IL-6) exhibited a marked increase in the serum at 3 h after the CeCl3 administration. In order to evaluate the involvement of IL-6 in the induction of MT by cerium, we examined MT induction by CeCl3 in IL-6 null mice. Both the induction of hepatic MT and the increases in SAA levels were markedly suppressed in IL-6 null mice. These results suggest that IL-6 plays an important role in the induction of hepatic MT by cerium.

© 2005 The Pharmaceutical Society of Japan
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