Effect of long term dexamethasone treatment on the glucocorticoid receptor
The ability of dexamethasone(dex) to induce alkaline phosphatase activity was found to decrease with chronic hormone exposure. In order to better understand this adaptive resistance, the structure of the receptor from control cells and cells under long term dex (10/sup -6/M) treatment was analyzed. Native isoelectric focusing showed that receptor from dex treated cells focused at more basic pI than receptor from control cells. Denaturing two-dimensional gel analysis resulted in the characteristic 4-5 spots of (/sup 3/H)dexamethasone mesylate (DM) binding of receptor from control cells, but no (/sup 3/H)DM binding could be seen for receptor from dex treated cells. In order to study DNA-binding characteristics, gels were renatured, transferred to nitrocellulose and probed with (/sup 32/P)MMTV-GRE. Receptor from control cells showed 5 spots of DNA-binding at 101 kDa molecular weight and a pI range of 7.42 to 7.32. However, receptor from dex treated cells showed less intense DNA-binding which occurred only at the more basic range of pIs (7.42 to 7.39). Furthermore, no nuclear receptor sites could be measured in the dex treated cells, whereas 20,000 sites were measured in control cells. Even after being taken off hormone treatment for 12 days, cells could regenerate only 50% of their receptors. In conclusion, this system is conducive to studying the mechanism of receptor regulation.
- Research Organization:
- Univ. of North Carolina, Chapel Hill
- OSTI ID:
- 7025105
- Report Number(s):
- CONF-8606151-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALKALINE PHOSPHATASE
ENZYME ACTIVITY
DEXAMETHASONE
BIOCHEMICAL REACTION KINETICS
GLUCOCORTICOIDS
RECEPTORS
DNA
MOLECULAR WEIGHT
PHOSPHORUS 32
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ADRENAL HORMONES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CORTICOSTEROIDS
DAYS LIVING RADIOISOTOPES
ENZYMES
ESTERASES
HORMONES
HYDROLASES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
KETONES
KINETICS
LABELLED COMPOUNDS
LIGHT NUCLEI
MEMBRANE PROTEINS
NUCLEI
NUCLEIC ACIDS
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PHOSPHATASES
PHOSPHORUS ISOTOPES
PREGNANES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
STEROID HORMONES
STEROIDS
550201* - Biochemistry- Tracer Techniques