Abstract
We have investigated the relationship between the catecholamine-induced occurrence in 1321N1 human astrocytoma cells of β-adrenergic receptors that exhibit low apparent affinity for hydrophilic ligands in short-time assays with intact cells and a population of β-adrenergic receptors that migrate in a light vesicle fraction on sucrose density gradients. Pretreatment of cells with concanavalin A prevents the generation of both of these forms of the receptor during incubation with agonists but does not prevent the agonist-induced decrease in isoproterenol-stimulated cyclic AMP production that also ocurs during desensitization. Selective labelling of the low affinity β-receptors with 125I-pindolol followed by centrifugation on sucrose density gradients revealed that all of the receptors in the light vesicle fraction from desensitized cells were of the low affinity type, but that a portion of the low affinity receptors also migrated in a heavier sucrose fraction together with the plasma membrane. In contrast, in control cells, no lower affinity receptors were present in the heavy sucrose fractions. The agonist-induced occurrence of these various forms of the β-adrenergic receptor can be explained on the basis of the current models of desensitization involving agonist-induced internalization of β-adrenergic receptors.
Original language | English (US) |
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Pages (from-to) | 11844-11850 |
Number of pages | 7 |
Journal | Journal of Biological Chemistry |
Volume | 259 |
Issue number | 19 |
State | Published - 1984 |
Externally published | Yes |
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology