Effects of cyclosporins and transforming growth factor β1 on thyroid hormone action in cultured fetal rat limb bones

Peter Lakatos*, Paula H. Stern

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

To study the mechanism of action of thyroid hormones on bone, we examined the effects of immunosuppresive and nonimmunosuppressive cyclosporins, as well as of transforming growth factor β1 (TGFβ1), 17β-estradiol (E2), and dihydroxytestosterone (DHT) on thyroxine (T4)-and triiodothyronine (T3)-stimulated bone resorption in fetal rat limb bones. The immunosuppressive cyclosporins A (CsA) and G (CsG) inhibited thyroid hormone (T4+T3)-stimulated resorption and β-glucuronidase release into the culture medium, whereas the weak or nonimmunosuppressive cyclosporins D (CsD) and H (CsH) did not show this effect. Increasing the medium calcium concentration reduced the ability of T4 to stimulate 45Ca release, while not significantly affecting the response to CsA. TGFβ1 elicited a biphasic effect when administered together with T4. During the first 3 days of culture, TGFβ1 elicited a small, nonsignificant decrease in released 45Ca; during a subsequent 3 days of culture, it enhanced T4-stimulated bone resorption significantly. These effects differed from those of TGFβ1 on parathormone-stimulated resorption. E2 and DHT did not influence the action of T4 on bone tissue. These results suggest that the mechanism of action of thyroid hormones on bone may involve immune factors, as well.

Original languageEnglish (US)
Pages (from-to)123-128
Number of pages6
JournalCalcified Tissue International
Volume50
Issue number2
DOIs
StatePublished - Feb 1992

Keywords

  • Bone resorption
  • Cyclosporins
  • TGFβ
  • Thyroid hormones

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Orthopedics and Sports Medicine
  • Endocrinology

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