A derivative of befunolol, BFE-55, interacts with only the high affinity sites in beta-adrenoceptors.
The effect of BFE-55, a derivative of befunolol (a beta-adrenergic partial agonist) on specific [3H]befunolol binding to a microsomal fraction from the guinea pig taenia caecum was tested. A Scatchard plot of specific [3H]befunolol binding in the absence of BFE-55 was concave, suggesting an existence of high and low affinity sites in beta-adrenoceptors. In contrast, the Scatchard plot of data in the presence of BFE-55 (3 X 10(-7) M) was straight. In the presence of BFE-55, the high affinity sites disappeared and the low affinity site was unaffected. In the absence and presence of BFE-55 there was no difference between the pKD values or Bmax values at the low affinity site. These findings indicate that BFE-55 interacts with only the high affinity sites in beta-adrenoceptors.
Koike
K
K
Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, Chiba, Japan.
Nakagoshi
A
A
Takayanagi
I
I
D000818:Animals; D002432:Cecum / Q000378:metabolism; D006168:Guinea Pigs; D007700:Kinetics; D008297:Male; D008861:Microsomes / Q000378:metabolism; D011412:Propanolamines / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*
D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; C052295:BFE 55; C006034:befunolol