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Ectopic beta-adrenergic receptor binding sites. possible molecular basis of aberrant catecholamine responsiveness of an adrenocortical tumor adenylate cyclase.

Publication ,  Journal Article
Williams, LT; Gore, TB; Lefkowitz, RJ
Published in: J Clin Invest
February 1977

The molecular basis for the aberrant catecholamine responsiveness of the adenylate cyclase of adrenocortical carcinoma 494 was explored. The adenylate cyclase of this corticosteroid-producing, transplanted, adrenal cancer of the rat was stimulated not only by adrenocorticotropic hormone and fluoride, but also by the beta-adrenergic agonist, isoproterenol. The adenylate cyclase of normal adrenal tissue was unresponsive to isoproterenol. Direct binding studies with the specific high affinity B-adrenergic ligand, (-)[3H]dihydroalprenolol, demonstrated the pressure of 0.094 pmol of specific binding sites per milligram of tumor membrane protein. By contrast, normal adrenal membranes contained too few binding sites to accurately measure and study using these techniques. The tumor binding sites had high affinity for (-)[3H] dihydroalprenolol with an equilibrium dissociation constant of 2.1 nM. Adrenergic agonists competed for the binding sites in an order of potency, [(-) isoproterenol greater than (-) epinephrine (-) norepinephrine], paralleling their order of potency as beta-adrenergic agonists. The beta-adrenergic antagonist, (-) propranolol, competed for binding, causing half-mzximal inhibition of specific binding at a concentration of 6 nM. The alpha-adrenergic antagonist, phentolamine, and several catecholamine metabolites and precursors did not effectively compete for the binding sites at high concentrations. Binding was stereospecific, the (+) stereoisomers of beta-adrenergic agonists and antagonists requiring 40- to 300-fold higher concentrations than the corresponding (-) stereoisomers to half maximally inhibit (-) [3H] dihydroalprenolol binding. These results indicate that adrenocortical carcinoma 494 membranes contain beta-adrenergic receptor-binding sites which are not normally present in membranes of adrenal tissue. These ectopic beta-adrenergic receptors presumably confer on the neoplastic tissue the catecholamine sensitivity of its adenylate cyclase.

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Published In

J Clin Invest

DOI

ISSN

0021-9738

Publication Date

February 1977

Volume

59

Issue

2

Start / End Page

319 / 324

Location

United States

Related Subject Headings

  • Receptors, Adrenergic, beta
  • Receptors, Adrenergic
  • Rats
  • Neoplasms, Experimental
  • Immunology
  • Catecholamines
  • Binding, Competitive
  • Binding Sites
  • Animals
  • Alprenolol
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Williams, L. T., Gore, T. B., & Lefkowitz, R. J. (1977). Ectopic beta-adrenergic receptor binding sites. possible molecular basis of aberrant catecholamine responsiveness of an adrenocortical tumor adenylate cyclase. J Clin Invest, 59(2), 319–324. https://doi.org/10.1172/JCI108643
Williams, L. T., T. B. Gore, and R. J. Lefkowitz. “Ectopic beta-adrenergic receptor binding sites. possible molecular basis of aberrant catecholamine responsiveness of an adrenocortical tumor adenylate cyclase.J Clin Invest 59, no. 2 (February 1977): 319–24. https://doi.org/10.1172/JCI108643.
Williams, L. T., et al. “Ectopic beta-adrenergic receptor binding sites. possible molecular basis of aberrant catecholamine responsiveness of an adrenocortical tumor adenylate cyclase.J Clin Invest, vol. 59, no. 2, Feb. 1977, pp. 319–24. Pubmed, doi:10.1172/JCI108643.

Published In

J Clin Invest

DOI

ISSN

0021-9738

Publication Date

February 1977

Volume

59

Issue

2

Start / End Page

319 / 324

Location

United States

Related Subject Headings

  • Receptors, Adrenergic, beta
  • Receptors, Adrenergic
  • Rats
  • Neoplasms, Experimental
  • Immunology
  • Catecholamines
  • Binding, Competitive
  • Binding Sites
  • Animals
  • Alprenolol