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Cellular site of glucocorticoid-receptor complex formation
Science (New York, N.Y.)
|January 14, 1972
Summary
Dexamethasone binds to glucocorticoid receptors inside cultured hepatoma cells, not at the cell membrane. Organic mercury compounds that do not enter cells confirmed this intracellular binding site for steroid-receptor complexes.
Area of Science:
- Biochemistry
- Cell Biology
- Pharmacology
Background:
- Glucocorticoid receptors mediate cellular responses to hormones like dexamethasone.
- Understanding the precise location of steroid-receptor binding is crucial for comprehending drug action.
Purpose of the Study:
- To determine the cellular location of dexamethasone binding to glucocorticoid receptors in cultured hepatoma cells.
- To differentiate between cell membrane and intracellular binding sites.
Main Methods:
- Utilized cultured hepatoma cells and specific mercurial compounds (p-chloromercuribenzene sulfonate, p-chloromercuribenzoate, HgCl2).
- Compared the effects of these mercurials on steroid-receptor binding in cell-free extracts versus whole cells.
Main Results:
- Organic mercury compounds (p-chloromercuribenzene sulfonate, p-chloromercuribenzoate) inhibited binding in cell-free extracts but not in whole cells.
- Mercuric chloride (HgCl2) inhibited binding in both cell-free extracts and whole cells.
- Organic mercury compounds showed limited cell penetration, suggesting intracellular binding.
Conclusions:
- Specific dexamethasone binding to glucocorticoid receptors occurs intracellularly within cultured hepatoma cells.
- The cell membrane is not the primary site for this steroid-receptor complex formation.