Regional and interspecific differences in the ligand binding properties of beta-adrenergic receptors of individual white adipose tissue depots in the sheep and rat.
The ligand binding of beta-adrenergic receptors was characterized in the omental, subcutaneous and popliteal adipose tissue depots in the sheep, and the lumbar and parametrial depots in the rat. Displacement of [125I]iodocyanopindolol ([125I]ICYP) binding to sheep adipose tissue membranes by the beta-adrenergic antagonists CGP 20712A and ICI 118,551 (beta 1- and beta 2-antagonists, respectively) suggested only a single ligand binding site predominantly beta 2 in character in all three depots, but revealed differences in affinity for these ligands between depots. Lactation increased beta-receptor ligand binding in subcutaneous and omental but not popliteal sheep adipose tissue depots, but had no effect on beta-adrenergic receptor affinities for CGP 20712A and ICI 118,551 in the three sheep adipose tissue depots studied. In rat adipocyte membranes, displacement of [125I]ICYP by CGP 20712A and ICI 118,551 was biphasic, indicating high and low affinity sites; displacement profiles differed markedly between lumbar and parametrial depots, the former having a preponderance of beta 1-like receptors and the latter a preponderance of beta 2-like receptors. The properties of the beta-adrenergic receptor binding site thus show species and depot specific differences.
Bowen
W P
WP
Hannah Research Institute, Ayr, U.K.
Flint
D J
DJ
Vernon
R G
RG
D000273:Adipose Tissue / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002462:Cell Membrane / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D020120:Iodocyanopindolol; D007774:Lactation; D010869:Pindolol / Q000031:analogs & derivatives / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D011506:Proteins / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*; D012756:Sheep
D007093:Imidazoles; D011412:Propanolamines; D011506:Proteins; D011943:Receptors, Adrenergic, beta; C026777:ICI 118551; D020120:Iodocyanopindolol; D010869:Pindolol; C049763:CGP 20712A