Possible Interaction: Triiodothyronine and Tiratricol

“The interpretation of thyroid function tests in this setting is further complicated by the fact that there is significant cross-reactivity between tiratricol and most T3 assays.”

“ T3 and rT3 concentrations increased, possibly due to a cross-reaction with Triac in their respective RIAs.”

“Monitored with the intracellular pH-sensitive fluorescent probe 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein, activation of … be initiated at the plasma membrane, because T3-agarose reproduced the effect of L-T3, and triiodothyroacetic acid , a hormone analog previously shown to … thyroid hormone, blocked the action of L-T3 ….”

“For inhibiting serum TSH levels, … g BW per day of TRIAC were significantly less active than 2 nmol/100 g BW … T4 or 1 nmol/100 g BW per day of T3 (TRIAC, serum TSH 35.5 +/- 5.7; T3 2.….91; T4 2.12 +/- 0.59 ng/ml).”

“Unlabeled T3, L-thyroxine (T4), 3,5,3'-triiodo-D-thyronine, and triiodothyroacetic acid inhibited T3 uptake with Kl values of 0.32, 1.4, 4.1, and 5.4 microM, respectively, indicating specificity of uptake which was different from specificity of intracellular binding sites.”

“When compared to T3, 27-, 135-, 500-, and 1000-fold higher concentrations of T4, 3,5-diiodothyronine (3,5-T2), triiodothyroacetic acid , and rT3, respectively, were needed to obtain 50% depression of the synaptosomal T3 binding.”

“Previous studies from this laboratory have shown that nuclear displacement of triiodothyronine (T3) is more rapidly dissipated after iv injection of triiodothyroacetic acid (triac) than after equimolar doses of T3.”

“Triiodothyroacetic acid Triac ) and T3 equally competed in inhibiting radiolabelled T3 binding while thyroxine (T4) was a poor competitor.”