Metallothionein gene expression in testicular interstitial cells and liver of rats treated with cadmium

The rodent testes are generally more susceptible to cadmium (Cd)-induced toxicity than the liver. Cd induces predominantly testicular interstitial cell (TIC) tumors. In order to clarify the molecular mechanism underlying tissue differences in Cd sensitivity, we compared Cd-induced metallothionein (M...

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Bibliographic Details
Published in:Toxicology (Amsterdam) 1996-02, Vol.107 (2), p.121-130
Main Authors: Mckenna, Ilda Melo, Bare, Robert M., Waalkes, Michael P.
Format: Article
Language:English
Subjects:
Animals
Base Sequence
Biological and medical sciences
Cadmium
Cadmium - administration & dosage
Cadmium - analysis
Cadmium - metabolism
Cadmium - toxicity
Chemical and industrial products toxicology. Toxic occupational diseases
Gene Expression - drug effects
Injections, Subcutaneous
Leydig Cells - chemistry
Leydig Cells - drug effects
Leydig Cells - metabolism
Liver
Liver - chemistry
Liver - drug effects
Liver - metabolism
Male
Medical sciences
Metallothionein
Metallothionein - biosynthesis
Metallothionein - genetics
Metals and various inorganic compounds
Molecular Sequence Data
Oligonucleotide Probes
Protein Binding
Rats
Rats, Inbred F344
RNA, Messenger - genetics
RNA, Messenger - metabolism
Testicular interstitial cells
Time Factors
Toxicology
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Summary:The rodent testes are generally more susceptible to cadmium (Cd)-induced toxicity than the liver. Cd induces predominantly testicular interstitial cell (TIC) tumors. In order to clarify the molecular mechanism underlying tissue differences in Cd sensitivity, we compared Cd-induced metallothionein (MT) gene expression, MT protein accumulation, and Cd retention in freshly isolated TICs and liver. Adult male Fischer rats received a s.c. injection of 4.0 μmol Cd/kg or vehicle and 24 h later tissues were sampled and TICs isolated. MT-I and MT-II mRNA levels were determined by slot-blot analysis followed by densitometry scanning, and MT was estimated by the Cd-heme method. Testicular lesions were not grossly or histologically observed in rats treated with 4 μmol Cd/kg. Both MT mRNA and MT (as determined by Cd-binding capacity) were constitutively present in TICs as well as the liver. TICs isolated from Cd-treated rats accumulated more Cd (4-fold), and had higher levels of MT-I ( 1.9-fold) and MT-II ( 1.4-fold) mRNAs over control, but contained less MT (30% decrease) than TICs isolated from control animals. Cd exposure substantially increased hepatic Cd content (6000-fold), MT (58-fold), and MT-I mRNA (5.3-fold), but did not increase MT-II mRNA. Thus, our findings indicate that, although low-dose Cd exposure results in increases of MT mRNA in TICs it does not enhance MT synthesis within these cells. The inability to induce the metal-detoxicating MT-protein, in response to Cd, might account for higher susceptibility of testes to Cd toxicity and Carcinogenesis relative to liver.
ISSN:0300-483X
1879-3185
DOI:10.1016/0300-483X(95)03252-B