Thyroxine downregulates Sox9 and promotes chondrocyte hypertrophy

Yasunori Okubo, A Hari Reddi

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


Thyroid hormones exert a profound effect on development, growth, and metabolism of skeleton. In the present study, we evaluated the effects of thyroxine (T4) and growth hormone (GH) on the terminal differentiation of rib growth plate chondrocytes in three-dimensional pellet culture. T4 (30ng/ml) stimulated the expressions of type II and X collagens, alkaline phosphatase (ALP) activity. On the other hand, the expression of chondrogenic transcription factor Sox9 in the T4 treatment group decreased significantly compared to the control group. T4 downregulates Sox9 and promotes hypertrophy. After day 7, T4 increases dramatically the synthesis of type X collagen mRNA, ALP activity, and cellular hypertrophy. Addition of GH does not modify the action of T4. Thus, T4 acts directly on chondrocytes. In conclusion, we demonstrated that T4 enhances the cellular and molecular events of terminal differentiation and hypertrophy of chondrocytes in the three-dimensional cultures.

Original languageEnglish (US)
Pages (from-to)186-190
Number of pages5
JournalBiochemical and Biophysical Research Communications
Issue number1
StatePublished - Jun 20 2003


  • Hypertrophy
  • Sox9
  • Terminal differentiation
  • Three-dimensional culture
  • Thyroxine

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology


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