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Induction and characterization of metallothionein in chicken epiphyseal growth plate cartilage chondrocytes.
- Source :
-
Journal of cellular biochemistry [J Cell Biochem] 1998 Jan 01; Vol. 68 (1), pp. 110-20. - Publication Year :
- 1998
-
Abstract
- Following exposure to cadmium or zinc, chickens were sacrificed and the liver, kidney, and bone epiphyseal growth plates harvested. When cytosolic extracts of the growth plate cartilage were fractionated by gel filtration chromatography, a protein with high metal-binding capacity and low ultraviolet (UV) absorbance eluted in the same position as liver metallothionein (MT) and a MT standard. Cd or Zn treatment resulted in a 25-fold or 5-fold induction in growth plate MT, respectively. In liver the greatest level of MT induction was seen with short-term Cd exposures. In contrast, MT levels in the growth plate increased as the duration of Cd exposure increased. Induction of MT in growth plate chondrocyte cell cultures was observed for media Cd concentrations of > or = 0.1 microM and Zn concentrations of > or = 100 microM. Basal and inducible levels of MT declined through the culture period and were lowest in the terminally differentiated mineralized late stages of the culture. Alkaline phosphatase activity was also lowest in the late-stage cultures, while total cellular protein increased throughout the culture period. Treatment of chondrocytes with Zn prior to Cd exposure resulted in a protective induction of MT. Pre-treatment of chondrocytes with dexamethasone resulted in suppressed synthesis of MT upon Cd exposure and greater Cd toxicity. Both Cd and Zn resulted in significantly increased levels of MT mRNA in chondrocyte cell cultures. Dexamethasone treatment resulted in an approximate 2- to 3-fold increase in MT mRNA. This is contrary to the finding that MT protein levels were decreased by dexamethasone. The findings suggest that an increased rate of MT degradation in dexamethasone-treated and late-stage chondrocyte cultures may be associated with the terminally differentiated phenotype.
- Subjects :
- Animals
Cadmium pharmacology
Cartilage cytology
Cartilage metabolism
Cells, Cultured
Chickens
Dexamethasone pharmacology
Epiphyses cytology
Epiphyses metabolism
Gene Expression Regulation
Growth Plate cytology
Growth Plate metabolism
Metallothionein genetics
Oxidoreductases drug effects
RNA, Messenger drug effects
RNA, Messenger genetics
RNA, Messenger metabolism
Time Factors
Tretinoin pharmacology
Zinc pharmacology
Chondrocytes cytology
Chondrocytes metabolism
Metallothionein analysis
Metallothionein drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 0730-2312
- Volume :
- 68
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Journal of cellular biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 9407319
- Full Text :
- https://doi.org/10.1002/(sici)1097-4644(19980101)68:1<110::aid-jcb11>3.0.co;2-l