|
|
||||||||
Journal of Animal Science, Vol 70, Issue 3 787-797, Copyright © 1992 by American Society of Animal Science
JOURNAL ARTICLE |
H. J. Mersmann and R. L. McNeel
Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030.
We measured ligand binding to the beta-adrenergic receptor from porcine adipocytes using tritiated radioligands, dihydroalprenolol (DHA) and CGP-12177 (CGP), and an iodinated radioligand, cyanopindolol (ICP). Binding was measured in a crude plasma membrane preparation. Equilibrium saturation binding was regular for all three ligands; the Kd were approximately 4,000 pM for DHA, 600 pM for CGP, and 100 pM for ICP. Binding was stereospecific with each radioligand. Association of each radioligand was relatively rapid; dissociation was rapid and complete for DHA, initially rapid but ultimately incomplete for CGP, and minimal for ICP. The Kd estimated from kinetic data were approximately 1,000 pM for DHA and 100 pM for CGP. The receptor did not bind phentolamine, an alpha-adrenergic antagonist, except at concentrations greater than 10(-5) M. Propranolol was bound to the receptor with a Ki of approximately 8 nM regardless of the radioligand used. Metoprolol, a purported beta 1-adrenergic specific antagonist, was bound to the receptor with a Ki of approximately 300 nM when the radioligands were CGP or ICP but with a Ki of approximately 1,000 nM when the radioligand was DHA. The Ki for ICI 118,551, a purported beta 2-adrenergic specific antagonist, were approximately 500 nM when the radioligands were DHA or CGP but 125 nM when the radioligand was ICP. Thus, the choice of radioligand can influence the characterization of the beta-adrenergic receptor being studied.
This article has been cited by other articles:
![]() |
M. N. Sillence, J. Hooper, G. H. Zhou, Q. Liu, and K. J. Munn Characterization of porcine {beta}1- and {beta}2-adrenergic receptors in heart, skeletal muscle, and adipose tissue, and the identification of an atypical {beta}-adrenergic binding site J Anim Sci, October 1, 2005; 83(10): 2339 - 2348. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. B. Smith, G. E. Carstens, R. D. Randel, H. J. Mersmann, and D. K. Lunt Brown adipose tissue development and metabolism in ruminants J Anim Sci, March 1, 2004; 82(3): 942 - 954. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. E. Mills, J. Kissel, C. A. Bidwell, and D. J. Smith Stereoselectivity of porcine {beta}-adrenergic receptors for ractopamine stereoisomers J Anim Sci, January 1, 2003; 81(1): 122 - 129. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. B. Izevbigie and W. G. Bergen {beta}-Adrenergic Agonist Hyperplastic Effect Is Associated with Increased Fibronectin Gene Expression and Not Mitogen-Activated Protein Kinase Modulation in C2C12 Cells Experimental Biology and Medicine, March 1, 2000; 223(3): 302 - 309. [Abstract] [Full Text] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |