Agonist-induced β-adrenergic receptor internalization on intact human mononuclear leukocytes: Effect of temperature of mononuclear leukocyte separation

Antonio De Blasi, Susanna Cotecchia, Maddalena Fratelli, Maria Lipartiti

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Abstract

The hydrophilic ligand 3H-CGP 12177 was used to measure β-adrenergic receptors on intact human mononuclear leukocytes (MNLs). A single homogeneous class of receptor sites was found, with KD value of 0.71 ± 0.04 nmol/L and Bmax, of 3.0 ± 0.4 fmol/106 cells (mean ± SEM; n = 12). The receptor affinity (KD) and density (Bmax) were similar when measured on MNLs, purified lymphocytes, and a T-lymphocyte enriched population from the same individual. Preincubation of intact MNLs with 1 μmol/L isoproterenol at 37 ° C for 20 minutes reduced the number of surface receptors, measured by 3H-CGP 12177 binding at 4 ° C for 20 hours, by ~70% (receptor internalization) without affecting KD. This effect was reversible, and surface receptors completely reappeared when binding was investigated at 37 ° C for 40 minutes. Receptor internalization was similar when either isolated MNLs or whole blood was incubated with isoproterenol. Agonistinduced receptor internalization was stable during MNL isolation from whole blood at 4 ° C but was partially or completely lost from MNLs prepared at 20 ° C.

Original languageEnglish
Pages (from-to)85
Number of pages1
JournalThe Journal of Laboratory and Clinical Medicine
Volume107
Issue number1
Publication statusPublished - 1986

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Mononuclear Leukocytes
Adrenergic Agonists
Temperature
Isoproterenol
Adrenergic Receptors
Lymphocytes
Ligands
T-Lymphocytes
Population

ASJC Scopus subject areas

  • Medicine(all)
  • Pathology and Forensic Medicine

Cite this

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title = "Agonist-induced β-adrenergic receptor internalization on intact human mononuclear leukocytes: Effect of temperature of mononuclear leukocyte separation",
abstract = "The hydrophilic ligand 3H-CGP 12177 was used to measure β-adrenergic receptors on intact human mononuclear leukocytes (MNLs). A single homogeneous class of receptor sites was found, with KD value of 0.71 ± 0.04 nmol/L and Bmax, of 3.0 ± 0.4 fmol/106 cells (mean ± SEM; n = 12). The receptor affinity (KD) and density (Bmax) were similar when measured on MNLs, purified lymphocytes, and a T-lymphocyte enriched population from the same individual. Preincubation of intact MNLs with 1 μmol/L isoproterenol at 37 ° C for 20 minutes reduced the number of surface receptors, measured by 3H-CGP 12177 binding at 4 ° C for 20 hours, by ~70{\%} (receptor internalization) without affecting KD. This effect was reversible, and surface receptors completely reappeared when binding was investigated at 37 ° C for 40 minutes. Receptor internalization was similar when either isolated MNLs or whole blood was incubated with isoproterenol. Agonistinduced receptor internalization was stable during MNL isolation from whole blood at 4 ° C but was partially or completely lost from MNLs prepared at 20 ° C.",
author = "{De Blasi}, Antonio and Susanna Cotecchia and Maddalena Fratelli and Maria Lipartiti",
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T1 - Agonist-induced β-adrenergic receptor internalization on intact human mononuclear leukocytes

T2 - Effect of temperature of mononuclear leukocyte separation

AU - De Blasi, Antonio

AU - Cotecchia, Susanna

AU - Fratelli, Maddalena

AU - Lipartiti, Maria

PY - 1986

Y1 - 1986

N2 - The hydrophilic ligand 3H-CGP 12177 was used to measure β-adrenergic receptors on intact human mononuclear leukocytes (MNLs). A single homogeneous class of receptor sites was found, with KD value of 0.71 ± 0.04 nmol/L and Bmax, of 3.0 ± 0.4 fmol/106 cells (mean ± SEM; n = 12). The receptor affinity (KD) and density (Bmax) were similar when measured on MNLs, purified lymphocytes, and a T-lymphocyte enriched population from the same individual. Preincubation of intact MNLs with 1 μmol/L isoproterenol at 37 ° C for 20 minutes reduced the number of surface receptors, measured by 3H-CGP 12177 binding at 4 ° C for 20 hours, by ~70% (receptor internalization) without affecting KD. This effect was reversible, and surface receptors completely reappeared when binding was investigated at 37 ° C for 40 minutes. Receptor internalization was similar when either isolated MNLs or whole blood was incubated with isoproterenol. Agonistinduced receptor internalization was stable during MNL isolation from whole blood at 4 ° C but was partially or completely lost from MNLs prepared at 20 ° C.

AB - The hydrophilic ligand 3H-CGP 12177 was used to measure β-adrenergic receptors on intact human mononuclear leukocytes (MNLs). A single homogeneous class of receptor sites was found, with KD value of 0.71 ± 0.04 nmol/L and Bmax, of 3.0 ± 0.4 fmol/106 cells (mean ± SEM; n = 12). The receptor affinity (KD) and density (Bmax) were similar when measured on MNLs, purified lymphocytes, and a T-lymphocyte enriched population from the same individual. Preincubation of intact MNLs with 1 μmol/L isoproterenol at 37 ° C for 20 minutes reduced the number of surface receptors, measured by 3H-CGP 12177 binding at 4 ° C for 20 hours, by ~70% (receptor internalization) without affecting KD. This effect was reversible, and surface receptors completely reappeared when binding was investigated at 37 ° C for 40 minutes. Receptor internalization was similar when either isolated MNLs or whole blood was incubated with isoproterenol. Agonistinduced receptor internalization was stable during MNL isolation from whole blood at 4 ° C but was partially or completely lost from MNLs prepared at 20 ° C.

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