-transparent.png){kind=logo}
(minus)-Alprenolol, a potent, competitive beta-adrenergic antagonist labeled to high specific activity with tritium (17 Ci per mmol), has been used to identify binding sites in frog erythrocyte membranes having many of the characteristics to be expected of the beta-adrenergic receptors which are linked to adenylate cyclase in these membranes. The chromatographic behavior and biological activity of the labeled and native drug were essentially identical. (minus)-Alprenolol and (minus)-[3-H]alprenolol both competitively antagonize isoproterenol stimulation of frog erythrocyte membrane adenylate cyclase with a KD OF 5 TO 10 NM. (minus)-[3-H]Alprenolol binding to sites in the frog erythrocyte membranes was studied by a centrifugal assay. At 37 degrees, equilibrium binding was established within 5 min and the half-time for dissociation of bound (minus)-[3-H]alprenolol was approximately 30 s. This rapid onset and dissociation of (minus)-[3-H]alprenolol binding was in good agreement with the rapid onset of action of beta-adrenergic agonists and antagonists on the frog erythrocyte adenylate cyclase. (minus)-[3-H]Alprenolol binding was saturable. There were 0.25 to 0.35 pmol of (minus)-[3-H]alprenolol binding sites per mg of protein corresponding to 1300 to 1800 binding sites per intact frog erythrocyte. The binding sites showed half-maximal saturation at 5.0 to 10 nM (minus)-[3-H]alprenolol, which is in good agreement with the KD for alprenolol antagonism of isoproterenol stimulation of adenylate cyclase. The (minus)-[3-H]alprenolol binding sites exhibited strict stereospecificity. (minus)-Stereoisomers of beta-adrenergic antagonists or agonists were approximately 2 orders of magnitude more potent than the (+)-stereoisomers in competing for the binding sites. Comparable stereospecificity was apparent when agonists and antagonists were tested for their ability to interact with the adenylate cyclase-coupled beta-adrenergic receptors in the membranes. Potency series of 11 agonists and 13 antagonists for inhibition of binding and interaction with adenylate cyclase were identical and were characteristic of a beta2-adrenergic receptor. A variety of nonphysiologically active compounds containing a catechol moiety as well as several metabolites and cholinergic agents did not inhibit (minus)-[3-H]alprenolol binding or interact significantly as agonists or antagonists with the adenylate cyclase. The (minus)-[3-H]alprenolol binding sites studied appear to be equivalent to the beta-adrenergic receptor binding sites in the frog erythrocyte membranes.
C Mukherjee, and
M G Caron, and
M Coverstone, and
R J Lefkowitz
September 1975,
Biochemical pharmacology,
C Mukherjee, and
M G Caron, and
M Coverstone, and
R J Lefkowitz
March 1975,
Biochemical pharmacology,
C Mukherjee, and
M G Caron, and
M Coverstone, and
R J Lefkowitz
April 1975,
Proceedings of the National Academy of Sciences of the United States of America,
C Mukherjee, and
M G Caron, and
M Coverstone, and
R J Lefkowitz
February 1984,
Biochemical and biophysical research communications,
C Mukherjee, and
M G Caron, and
M Coverstone, and
R J Lefkowitz
January 1986,
Clinical neuropharmacology,
C Mukherjee, and
M G Caron, and
M Coverstone, and
R J Lefkowitz
August 1981,
Biochemical and biophysical research communications,
C Mukherjee, and
M G Caron, and
M Coverstone, and
R J Lefkowitz
January 1981,
Advances in cyclic nucleotide research,
C Mukherjee, and
M G Caron, and
M Coverstone, and
R J Lefkowitz
May 1985,
The Journal of clinical endocrinology and metabolism,
C Mukherjee, and
M G Caron, and
M Coverstone, and
R J Lefkowitz
January 1979,
Biochemical pharmacology,
C Mukherjee, and
M G Caron, and
M Coverstone, and
R J Lefkowitz
July 1979,
Biochimica et biophysica acta,
