Related Experiment Video
Updated: Jul 13, 2026

Induction of Myocardial Infarction and Myocardial Ischemia-Reperfusion Injury in Mice
Published on: January 19, 2022
Thyroid function disturbance and type 3 iodothyronine deiodinase induction after myocardial infarction in rats a time
Emerson L Olivares1, Michelle P Marassi, Rodrigo S Fortunato
1Departamento de Ciências Fisiológicas, Instituto de Biologia, Universidade Federal Rural do Rio de Janeiro BR 465, Km 7, 23851-000 Seropédica, Rio de Janeiro, Brazil. elopes@ufrrj.br
Abstract:
In humans, there is a significant decrease in serum T(3) and increase in rT(3) at different time points after myocardial infarction, whereas serum TSH and T(4) remain unaltered. We report here a time course study of pituitary-thyroid function and thyroid hormone metabolism in rats subjected to myocardial infarction by left coronary ligation (INF). INF- and sham-operated animals were followed by serial deiodination assays and thyroid function tests, just before, and 1, 4, 8, and 12 wk after surgery. At 4 and 12 wk after INF, liver type 1 deiodinase activity was significantly lower, confirming tissue hypothyroidism. Type 3 deiodinase (D3) activity was robustly induced 1 wk after INF only in the infarcted myocardium. Reminiscent of the consumptive hypothyroidism observed in patients with large D3-expressing tumors, this induction of cardiac D3 activity was associated with a decrease in both serum T(4) ( approximately 50% decrease) and T(3) (37% decrease), despite compensatory stimulation of the thyroid. Thyroid stimulation was documented by both hyperthyrotropinemia and radioiodine uptake. Serum TSH increased by 4.3-fold in the first and 3.1-fold in the fourth weeks (P < 0.01), returning to the basal levels thereafter. Thyroid sodium/iodide-symporter function increased 1 wk after INF, accompanying the increased serum TSH. We conclude that the acute decrease in serum T(4) and T(3) after INF is due to increased thyroid hormone catabolism from ectopic D3 expression in the heart.
Related Concept Videos
Hyperthyroidism II: Pathophysiology
Synthesis and Regulation of Thyroid Hormones
Upon reaching the thyroid gland, TSH stimulates the follicular cells' active uptake of iodide ions from the blood. The ions diffuse to the apical surface of the cells and are oxidized to iodine. The iodine is then...
Hyperthyroidism I: Introduction
Hypothyroidism II: Pathophysiology
Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers
Myocarditis III: Medical Management
