Thyroid hormone stimulates myoglobin gene expression in rat cardiac muscle

• Published in: Molecular and cellular endocrinology Vol. 226; no. 1; pp. 19 - 26
• Main Authors: Giannocco, Gisele, DosSantos, Rosangela A., Nunes, Maria Tereza
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier Ireland Ltd 29-10-2004
• Subjects: Animals; Blotting, Northern; Blotting, Western; Cardiac muscle; Gene Expression - drug effects; Heart Atria - drug effects; Heart Atria - metabolism; Heart Ventricles - drug effects; Heart Ventricles - metabolism; Hyperthyroidism; Hypothyroidism; Male; Myocardium - metabolism; Myoglobin - genetics; Myoglobin - metabolism; Myoglobin expression; Rats; Rats, Wistar; Thyroid hormone; Thyroid Hormones - pharmacology; Thyroid hormone; Cardiac muscle; Hypothyroidism; Hyperthyroidism; Myoglobin expression
• ISSN: 0303-7207; 1872-8057
• DOI: 10.1016/j.mce.2004.07.007

T
3 increases the heart activity, O
2 consumption and the reactive O
2 species production. Myoglobin (Mb) is highly expressed in the heart, where it facilitates O
2 diffusion, mitochondrial respiration, and scavenges reactive O
2 species. Here we investigate, by dose–response (0.3–100
μg/100
g BW, i.p., 5 days) and time-course studies (100
μg/100
g BW, i.v., from 0.5 to 24
h), whether T
3 affects the Mb mRNA and protein expression in atrium (A) and ventricle (V), by Northern and Western blot. We show that the Mb gene is controlled by T
3 in A and V, as indicated by Mb mRNA and protein content decrease in thyroidectomized (Tx) rats, and restoration by T
3 treatment. In the A, the different doses of T
3 induced the Mb mRNA and protein recovery to the euthyroid levels; in the time-course study, this occurred only with the protein levels. In the V, T
3 progressively increased the Mb mRNA above the euthyroid levels at a dose of 25
μg/100
g BW; higher doses decreased it to the euthyroid levels. Mb protein increased only to the euthyroid levels at all T
3 doses injected. The time-course study showed a progressive increase in the ventricular Mb mRNA and protein, which exceeded the euthyroid levels from 6 to 24
h, and at 2 and 6
h of the T
3 treatment, respectively. We conclude that heart Mb gene expression is influenced by thyroid status.