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In vivo Characterization of Endocrine Disrupting Chemical Effects via Thyroid Hormone Action Indicator Mouse
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In vivo Characterization of Endocrine Disrupting Chemical Effects via Thyroid Hormone Action Indicator Mouse

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Thyroid hormone receptor-α and vascular function

Ayako Makino1, Hong Wang, Brian T Scott

  • 1Section of Endocrinology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA.

American Journal of Physiology. Cell Physiology
|February 11, 2012
PubMed

Insights

Thyroid hormone (TH) receptors, specifically TRα, regulate coronary vascular tone. TH treatment decreases vascular tone by increasing K(+) channel activity via TRα in smooth muscle cells.

Area of Science:

  • Cardiovascular Physiology
  • Endocrinology
  • Molecular Biology

Background:

  • Thyroid hormone (TH) benefits cardiovascular health, including lowering cholesterol and improving cardiac function.
  • The role of TH receptors (TRs) in regulating vascular tone remains largely unexplored.
  • Understanding TRs' function in vascular smooth muscle is crucial for cardiovascular health.

Purpose of the Study:

  • To investigate the contribution of TR subtypes to vascular contractility in the heart.
  • To determine the specific TR subtype predominant in coronary smooth muscle cells (SMCs).
  • To elucidate the mechanism by which TH influences vascular tone.

Main Methods:

  • Utilizing TR subtype-specific knockout (KO) mice to assess vascular contraction.
  • Isolating and analyzing coronary arteries and SMCs from wild-type and KO mice.
  • Measuring K(+) channel activity in SMCs under varying conditions of TH treatment and TRα deficiency.

Main Results:

  • Coronary arteries from TRα KO mice showed significantly enhanced vascular contraction compared to wild-type.
  • Chronic TH treatment attenuated coronary vascular contraction.
  • TRα was identified as the predominant TR in mouse coronary SMCs.
  • TRα KO SMCs exhibited decreased K(+) channel activity, while TH treatment dose-dependently increased it.

Conclusions:

  • TRα in SMCs plays a prominent role in regulating vascular tone.
  • TH treatment decreases coronary vascular tone by enhancing K(+) channel activity through TRα in SMCs.
  • These findings highlight a novel mechanism for TH in cardiovascular regulation.

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