Effect of amiodarone on L-triiodothyronine stimulation of [3H] thymidine incorporation into GH3 cells

  • I. D. Goldfine
  • B. Maddux
  • K. A. Woeber


The antiarrhythmic agent amiodarone was found to inhibit the stimulatory effects of L-triiodothyronine on [3H ] thymidine incorporation into GH3 rat pituitary tumor cells. This inhibitory effect of amiodarone was detected at concentrations as low as 0.5 μM; at 2 μM greater than 50% of the stimulatory effect of L-triiodothyronine was inhibited. The effect of amiodarone was present at all concentrations of L-triiodothyronine tested (50 pM to 10 nM), suggesting that amiodarone acted as a non-competitive antagonist. These studies raise the possibility, therefore, that the effect of amiodarone on thyroid hormone metabolism may be mediated in part by an inhibition of thyroid hormone action at the cellular level.


L-triiodothyronine amiodarone GH3 cells 


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Copyright information

© Italian Society of Endocrinology (SIE) 1982

Authors and Affiliations

  • I. D. Goldfine
    • 1
    • 2
    • 3
  • B. Maddux
    • 1
  • K. A. Woeber
    • 1
    • 2
  1. 1.Cell Biology Laboratory and Department of MedicineMount Zion Hospital and Medical CenterSan FranciscoUSA
  2. 2.Department of MedicineUniversity of CaliforniaSan FranciscoUSA
  3. 3.Department of PhysiologyUniversity of CaliforniaSan FranciscoUSA

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