Modes of Determining β‐Adrenoceptor Number in Human Mononuclear Leucocytes
- 1 October 1987
- journal article
- research article
- Published by Wiley in Basic & Clinical Pharmacology & Toxicology
- Vol. 61 (4), 265-270
- https://doi.org/10.1111/j.1600-0773.1987.tb01816.x
Abstract
Inhibition of total 125I-ICYP binding to intact human mononuclear leucocytes at 32 by propranolol and (.+-.) CGP-12177 was biphasic. The high affinity component of 125I-CYP binding, representing approximately 30% of total, was stereospecific, while the low affinity binding site was inhibited without stereospecificity. (-) Isoproterenol inhibited the high affinity component of 125I-ICYP binding only, with low affinity. By performing binding studies in intact cells at 4.degree. or in broken cell preparations at 37, the fraction of total 125I-ICYP binding representing specific binding was increased, and agonist affinity was high. Inhibition of 3H-CGP-12177 binding to intact cells at 32.degree. demonstrated a high fraction of specific binding and high agonist affinity. Computer-assisted analysis of total radioligand binding determined over a broad concentration range revealed two populations of saturable 125I-CYP binding sites in intact cells as well as in broken cell preparations, while 3H-CGP-12177 binding demonstrated only one saturable binding site. The number of high affinity 125I-CYP binding sites was comparable to the number of saturable 3H-CGP-12177 binding sites. Receptor numbers determined by analysis of total radioligand binding were comparable to receptor numbers determined by subtraction of non-specific binding, determined in the presence of a high concentration of competing ligand. Analysis of total radioligand binding was found to be a better procedure because it eliminates the use of an arbitrary concentration of unlabelled ligand and improves the accuracy of the assay.This publication has 30 references indexed in Scilit:
- Effect of Serum, α-1 Acid Glycoprotein, Lipoproteins and Albumin on Human Mononuclear Leucocyte β-AdrenoceptorsActa Pharmacologica et Toxicologica, 2009
- Uptake of l-[propyl-2,3-3H]dihydroalprenolol by intact HeLa cellsBiochimica et Biophysica Acta (BBA) - Molecular Cell Research, 1984
- Trapping of labelled ligands in intact cells: A pitfall in binding studiesBiochemical Pharmacology, 1983
- Adrenergic Receptors in ManNew England Journal of Medicine, 1982
- Non-specific uptake of the radioligand 125I-IHYP by intact human lymphocytes: Reversal of the uptake processMolecular and Cellular Endocrinology, 1982
- The β-adrenergic receptor in human lymphocytes: Subclassification by the use of a new radio-ligand, (±)−125iodocyanopindololLife Sciences, 1981
- The uptake of amines by polymorphonuclear leukocytesBiochimica et Biophysica Acta (BBA) - Biomembranes, 1981
- Identification of beta-adrenergic receptors in human lymphocytes by (-) (3H) alprenolol binding.Journal of Clinical Investigation, 1976
- Relationship between the inhibition constant (KI) and the concentration of inhibitor which causes 50 per cent inhibition (I50) of an enzymatic reactionBiochemical Pharmacology, 1973
- THE ATTRACTIONS OF PROTEINS FOR SMALL MOLECULES AND IONSAnnals of the New York Academy of Sciences, 1949