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Updated: Aug 15, 2026

Generation of Hypoparathyroid Rats via Carbon-Nanoparticle-Assisted Parathyroidectomy
Published on: July 14, 2023
Hepatic poly(ADP-ribose) polymerase activity in rat is controlled by thyroid hormones
C F Cesarone1, L Scarabelli, P Giannoni
1Institute of General Physiology, University of Genoa, Italy.
Abstract:
The in vivo effect of the thyroidal state on poly(ADP-ribose) polymerase activity was investigated in eu- and hypothyroid rats after treatment with L-triiodothyronine. Untreated hypothyroids showed an increased basal rate of the enzyme. The treatment of both eu- and hypothyroid rats with L-triiodothyronine induced a prompt drop of the endogenous activity not due to a reduction of the catalytic protein. This decrease well evident 1 h after treatment was transient, returning to controls values within 8 h. In isolated liver nuclei from euthyroids the in vitro exposure to increasing L-triiodothyronine concentrations from 10(-18) to 10(-6) M resulted in a progressive inhibition of the enzyme. This loss in activity was not derived from a reduction of the total level of the catalytic protein. The pretreatment with the antagonist amiodarone suppressed the hormone effect, suggesting that nuclear receptors could mediate poly(ADP-ribose) polymerase activity.
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