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Thyroid hormone regulation of alpha-adrenergic receptors: studies in rat myocardium.

Publication ,  Journal Article
Williams, RS; Lefkowitz, RJ
Published in: J Cardiovasc Pharmacol
1979

The effects of alterations in thyroid state on cardiac alpha-adrenergic receptors were investigated by the binding of [3H]dihydroergocryptine (DHE), a potent alpha-adrenergic antagonist. In seven experiments, cardiac membranes from euthyroid rats bound 47 +/- 9 fmoles DHE/mg protein (mean +/- SE) at saturation and demonstrated a dissociation constant (KD) of 2.5 +/- 0.4 nM. Hyperthyroidism, produced by parenteral injection of triiodothyronine, significantly reduced the binding of DHE at all concentrations studied. Scatchard analysis showed this reduction of binding to be due largely to a decreased affinity (KD = 4.0 +/- 0.8 nM, p less than 0.05), although possibly due to a decreased number of binding sites as well (29 +/- 7 fmoles/mg protein, p less than 0.10). Hypothyroidism, produced either by oral propylthiouracil or by surgical thyroidectomy, did not produce a significant change in either the number of binding sites for DHE (56 +/- 8 fmoles/mg protein, p less than 0.40) or in binding affinity (KD = 3.1 +/- 0.5 nM, p less than 0.40). Thus, in addition to the regulation of cardiac beta-receptors by thyroid hormone that has been described previously, thyroid hormone exerts a regulatory effect on the characteristics of cardiac alpha-receptors as well. These changes provide a possible molecular mechanism for the thyroid hormone-induced alterations in cardiac responsiveness to alpha-adrenergic stimulation that have been reported previously.

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Published In

J Cardiovasc Pharmacol

DOI

ISSN

0160-2446

Publication Date

1979

Volume

1

Issue

2

Start / End Page

181 / 189

Location

United States

Related Subject Headings

  • Thyroidectomy
  • Thyroid Hormones
  • Receptors, Adrenergic, alpha
  • Receptors, Adrenergic
  • Rats
  • Myocardium
  • Male
  • Kinetics
  • Hypothyroidism
  • Hyperthyroidism
 

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Williams, R. S., & Lefkowitz, R. J. (1979). Thyroid hormone regulation of alpha-adrenergic receptors: studies in rat myocardium. J Cardiovasc Pharmacol, 1(2), 181–189. https://doi.org/10.1097/00005344-197903000-00002
Williams, R. S., and R. J. Lefkowitz. “Thyroid hormone regulation of alpha-adrenergic receptors: studies in rat myocardium.J Cardiovasc Pharmacol 1, no. 2 (1979): 181–89. https://doi.org/10.1097/00005344-197903000-00002.
Williams RS, Lefkowitz RJ. Thyroid hormone regulation of alpha-adrenergic receptors: studies in rat myocardium. J Cardiovasc Pharmacol. 1979;1(2):181–9.
Williams, R. S., and R. J. Lefkowitz. “Thyroid hormone regulation of alpha-adrenergic receptors: studies in rat myocardium.J Cardiovasc Pharmacol, vol. 1, no. 2, 1979, pp. 181–89. Pubmed, doi:10.1097/00005344-197903000-00002.
Williams RS, Lefkowitz RJ. Thyroid hormone regulation of alpha-adrenergic receptors: studies in rat myocardium. J Cardiovasc Pharmacol. 1979;1(2):181–189.

Published In

J Cardiovasc Pharmacol

DOI

ISSN

0160-2446

Publication Date

1979

Volume

1

Issue

2

Start / End Page

181 / 189

Location

United States

Related Subject Headings

  • Thyroidectomy
  • Thyroid Hormones
  • Receptors, Adrenergic, alpha
  • Receptors, Adrenergic
  • Rats
  • Myocardium
  • Male
  • Kinetics
  • Hypothyroidism
  • Hyperthyroidism