Parathyroid hormone (PTH) inhibits terminal chondrocyte differentiation and type X collagen production in cultured whole chick sterna. Academic Article uri icon


  • In cartilage, hypertrophy is the terminal stage of chondrocyte differentiation. Type X collagen expression is a marker for this stage of development. PTH has been shown to repress articular cartilage differentiation. PTH is also required for normal chondrocyte development through the prehypertrophic stage. We used a serum-free whole chick sterna model to determine PTH effects on chondrocyte terminal differentiation using type X collagen expression as a marker. We addressed the following questions. 1) Does PTH inhibit terminal differentiation of hyaline cartilage chondrocytes? 2) Are PTH effects dose dependent? 3) Is there a temporal window when PTH is more effective? 14 day sterna were cultured for 8 days in PTH concentrations ranging from 10-5 to 10-7M and examined for type X collagen expression. Type X collagen was detected using immuno-histochemistry and visualized with confocal microscopy. Increasing PTH concentration led to decreased type X collagen expression. To determine stage dependent effects, 14 day sterna were given one dose of 10-7 M PTH on one day of the first 7 days of culturing. Sternal lengths after 24 hr. exposure to PTH were determined. PTH increased sternal length only until day 6 of culture. In conclusion, our results suggest that PTH may inhibit hyaline cartilage development in the prehypertrophic stages and has minimal effect on cells that have entered terminal differentiation.

published proceedings


author list (cited authors)

  • Lunsford, L. E., Hirsch, M. S., & Svoboda, K.

complete list of authors

  • Lunsford, LE||Hirsch, MS||Svoboda, KKH

publication date

  • January 1997