Related Experiment Video

Updated: Aug 16, 2026

In vivo Characterization of Endocrine Disrupting Chemical Effects via Thyroid Hormone Action Indicator Mouse
04:14

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

Published on: October 6, 2023

Contrasting skeletal phenotypes in mice with an identical mutation targeted to thyroid hormone receptor alpha1 or

Patrick J O'Shea1, J H Duncan Bassett, Srividya Sriskantharajah

  • 1Molecular Endocrinology Group, 5th Floor Clinical Research Building, Medical Research Council Clinical Sciences Centre, Hammersmith Hospital, Du Cane Road, London W12 0NN, United Kingdom.

Molecular Endocrinology (Baltimore, Md.)
|July 30, 2005
PubMed

Insights

Thyroid hormone receptors TRalpha1 and TRbeta play distinct roles in bone development. TRalpha1 is crucial for skeletal growth and mineralization, while TRbeta influences thyroid hormone resistance.

Area of Science:

  • Endocrinology
  • Skeletal Biology
  • Molecular Genetics

Background:

  • Thyroid hormone (T3) is vital for adult bone turnover and skeletal development.
  • Thyroid hormone receptors (TRs) mediate T3's actions.
  • Specific roles of TRalpha1 and TRbeta in bone remain incompletely understood.

Purpose of the Study:

  • To investigate the distinct roles of TRalpha1 and TRbeta in skeletal development and thyroid hormone action in bone.
  • To elucidate the mechanisms by which TRs regulate bone growth, mineralization, and hormone signaling.

Main Methods:

  • Utilized genetically engineered mouse models with targeted mutations in TRalpha1 (TRalpha1(PV)) and TRbeta (TRbeta(PV)).
  • Analyzed skeletal phenotypes, including ossification, bone deposition, mineralization, and suture closure.
  • Assessed growth hormone (GH) receptor and insulin-like growth factor-I (IGF-I) receptor expression and signaling in growth plates.

Main Results:

  • TRalpha1(PV) mice exhibited skeletal hypothyroidism with delayed ossification, growth retardation, and impaired bone mineralization.
  • TRbeta(PV) mice displayed skeletal thyrotoxicosis with increased GH and IGF-I receptor signaling.
  • GH and IGF-I receptors are identified as physiological targets of T3 action in bone.

Conclusions:

  • TRalpha1 mediates T3's anabolic effects on bone, essential for skeletal development and growth.
  • TRbeta primarily influences systemic thyroid hormone sensitivity, impacting bone indirectly via central mechanisms.
  • Differential tissue responsiveness to TR isoforms explains the distinct skeletal phenotypes observed.

More Related Videos

Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model08:42

Skeletal Phenotype Analysis of a Conditional Stat3 Deletion Mouse Model

Published on: July 3, 2020

A Versatile, Behavioral Method to Investigate Thyroid Hormone Effects on Cerebellar Function04:05

A Versatile, Behavioral Method to Investigate Thyroid Hormone Effects on Cerebellar Function

Published on: October 6, 2023

Related Concept Videos

Lethal Alleles02:41

Lethal Alleles

Agouti: A Lethal Allele
Lucien Cuénot discovered lethal alleles in 1905 while studying the inheritance of coat color in mice. The agouti gene is responsible for the color of the coat in mice. This gene codes for an agouti-signaling protein, which is responsible for melanin distribution in mammals. The wild-type allele gives rise to gray-brown coat color in mice, while the mutant allele gives rise to yellow coat color. In addition to coat color, the agouti gene is associated with the yellow...
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase01:11

Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase

Genetic polymorphisms in drug targets have emerged as critical determinants of interindividual variability in drug response and toxicity. Pharmacogenomic investigations increasingly focus on identifying these variations to personalize and optimize therapeutic interventions. A drug target may be a receptor, enzyme, or signaling protein involved in pharmacologic responses or disease-related pathways. While early pharmacogenetic studies focused primarily on drug metabolism, current research...
Epistasis01:39

Epistasis

In addition to multiple alleles at the same locus influencing traits, numerous genes or alleles at different locations may interact and influence phenotypes in a phenomenon called epistasis. For example, rabbit fur can be black or brown depending on whether the animal is homozygous dominant or heterozygous at a TYRP1 locus. However, if the rabbit is also homozygous recessive at a locus on the tyrosinase gene (TYR), it will have an unshaded coat that appears white, regardless of its TYRP1...