Combined replacement therapy with T4
and T3 (in proportions similar to those secreted by the normal rat thyroid)
completely restored euthyroidism in thyroidectomized rats at much lower
doses of T4 than those needed to normalize T3 in most tissues when T4 alone
was used
The most striking abnormality detected in 75 sick euthyroid patients was a highly significant reduction in the mean total serum-triiodothyronine (T3) levels, with most patients having total T3 levels in the hypothyroid range. The severity of the illness correlated well with the reduction in total serum-T3 levels.
Both pregnancy and estrogen administration were associated with increases in serum reverse T3 concentrations presumably because of their ability to augment thyroxine binding globulin synthesis.
The effects of T3 on cancer cell lines varies. All cell lines came from the same tissue. It doesn't appear that simply stating T3 promotes cellular metabolism and thus provides an increase in cancer progression risk. Some cell lines studies actually had an inhibition of cell growth, whereas others saw an increase.
proportionally associated with disease severity and survival
nonthyroidal illness syndrome
Patients with persistent deterioration of hormone levels (T3, T4) during the study period had higher mortality than those who normalized the function of the thyroid axis
LT3S in patients with septic shock is part of the pathophysiology of this disease and/or an associated organ (endocrine-metabolic) failure and not just an adaptive phenomenon
substitution treatment with synthetic thyroid hormones could modify the hemodynamic symptoms of septic patients, contributing in part to the decrease in their morbidity and mortality