Induction and characterization of hepatic metallothionein expression from cadmium-induced channel catfish (Ictalurus punctatus)

Journal Article · Tue Aug 01 04:00:00 EDT 1995 · Environmental Toxicology and Chemistry

DOI:https://doi.org/10.1002/etc.5620140820· OSTI ID:94323

Zhang, Y S ^[1]; Schlenk, D ^[2]

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1. State Oceanic Administration, Fujian (China)
2. Univ. of Mississippi, University, MS (United States). Dept. of Pharmacology

Two low-molecular-weight proteins of approximately 10,000 daltons (DA) were isolated from the hepatic tissue of catfish intraperitoneally injected with CdCl{sub 2} (5 mg/kg). Each protein was significantly induced following Cd treatment. Bound Cd, co-eluted from DEAE anion-exchange HPLC with rabbit hepatic metallothioneins I and II, did not possess UV absorption indicative of aromatic amino acids and corresponded to the expression of two mRNA transcripts of approximately 400 base pairs, which hybridized to a full-length cDNA probe to winter flounder metallothionein (MT). Because these data indicated that these two low molecular weight proteins were hepatic MT isoforms, induction of MT mRNA expression was studied in livers of channel catfish exposed to aqueous CdCl{sub 2} utilizing the ribonuclease protection assay. Following a 7-d exposure to 10, 50, and 100 {micro}g/L CdCl{sub 2}, expression of two MT mRNAs increased in a dose-dependent manner (MT-a, r{sup 2} = 0.95; MT-b, r{sup 2} = 0.98). Each transcript was maximally induced 48 h after exposure to 100 {micro}g/L CdCl{sub 2} and then gradually declined to approximately 20% above controls after 96 h and maintained this level of expression for 7 d. Although MT expression is rapidly induced in channel catfish by Cd, and MT mRNA measurement is a sensitive indicator of MT induction, the use of hepatic MT of channel catfish may not be a sensitive bioindicator of short-term, low-level aqueous exposures of Cd.

• Sponsoring Organization: USDOE
• OSTI ID: 94323
• Journal Information: Environmental Toxicology and Chemistry, Journal Name: Environmental Toxicology and Chemistry Journal Issue: 8 Vol. 14; ISSN 0730-7268; ISSN ETOCDK
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
BIOASSAY
BIOLOGICAL INDICATORS
BIOSYNTHESIS
CADMIUM
CHEMICAL COMPOSITION
ION EXCHANGE
LIQUID COLUMN CHROMATOGRAPHY
METALLOTHIONEIN
WATER POLLUTION