Induction of metallothioneins (MT) by dexamethasone determined at isoprotein and messenger RNA levels
In this study induction of MT-I and MT-II by dexamethasone (DEX), a primary inducer of MT, was determined by HPLC analysis of protein and Northern blot analysis of MT mRNAs. Rats were injected with DEX (0.03-10 umol/kg) and 24 hrs later, hepatic concentrations of MTs were determined. In controls, only MT-II was detected (9.4 +/- 2.5 ug/g). DEX did not increase MT-I above the detection limit (5 ug/g) at any dosage whereas MT-II increased to 2.5-times control at dosages of 1 umol/kg and higher. Time-course experiments indicated that MT-II reached a maximum at 24 hrs and returned to control levels by 48 hrs whereas MT-I was never detected. To increase sensitivity of the HPLC assay, samples wee saturated with /sup 109/Cd prior to analysis. Results indicated that at 24 hrs, DEX (1 umol/kg) increased MT-I and MT-II to 1.5- and 2.5-times control levels, respectively. Northern blot hybridization with mouse cRNA probes indicated that 6 hrs after DEX injection, MT-I and MT-II mRNAs reached maximal levels of 2.9- and 3.7-times control levels, respectively, and returned to control levels by 12 hrs. Thus, in rats MT-II is more abundant than MT-I and preferentially accumulates following administration of DEX, and although MT mRNAs are induced coordinately by DEX, MT-II mRNA increases more than MT-I mRNA.
- Research Organization:
- Univ. of Kansas Medical Center, Kansas City
- OSTI ID:
- 5435955
- Report Number(s):
- CONF-8604222-; TRN: 86-026633
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:3; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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DEXAMETHASONE
BIOLOGICAL EFFECTS
METALLOTHIONEIN
METABOLISM
CADMIUM 109
LIQUID COLUMN CHROMATOGRAPHY
LIVER
MESSENGER-RNA
RATS
TRACER TECHNIQUES
ADRENAL HORMONES
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
CADMIUM ISOTOPES
CHROMATOGRAPHY
CORTICOSTEROIDS
DIGESTIVE SYSTEM
ELECTRON CAPTURE RADIOISOTOPES
EVEN-ODD NUCLEI
GLANDS
GLUCOCORTICOIDS
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HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
KETONES
MAMMALS
METALLOPROTEINS
NUCLEI
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PREGNANES
PROTEINS
RADIOISOTOPES
RNA
RODENTS
SEPARATION PROCESSES
STEROID HORMONES
STEROIDS
VERTEBRATES
YEARS LIVING RADIOISOTOPES
550201* - Biochemistry- Tracer Techniques