Abstract
To determine if New World primates express an inhibitor that influences glucocorticoid receptor (GR) binding characteristics, we examined [3H] dexamethasone binding in cytosol prepared from B95-8 lymphoid cells, derived from the cotton top tamarin (Saguinus oedipus), in combination with cytosol prepared from human or rat tissues. B95-8 cytosol inhibited specific binding of [3H]dexamethasone (P < 0.01) when mixed with cytosol prepared from either a human lymphoid cell line (HL) or rat thymus. The inhibitory activity was heat labile and trypsin sensitive. Peak inhibitory activity was found in the 150-200 kd fractions after Sephacryl G-200 ultrafiltration. Scatchard analysis of [3H]dexamethasone binding using mixed cytosol showed a diminished GR apparent binding affinity when compared to HL cytosol. Kinetic studies using mixed cytosol indicated that B95-8 cytosol did not affect the apparent dissociation rate of [3H] dexamethasone. These data demonstrate that B95-8 cells contain a competitive inhibitor that prevents binding of dexamethasone to its cognate receptor.
Original language | English (US) |
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Pages (from-to) | 463-466 |
Number of pages | 4 |
Journal | Steroids |
Volume | 60 |
Issue number | 7 |
DOIs | |
State | Published - Jul 1995 |
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Endocrinology
- Pharmacology
- Clinical Biochemistry
- Organic Chemistry