Related Experiment Videos
Thyroxine effects on serum insulin-like growth factor I levels, anthropometric measures, and body composition in
Ta-Jen Wu1, Shih-Ming Huang, Robert L Taylor
1Department of Internal Medicine, National Cheng Kung University Hospital, Taiwan, Republic of China.
Abstract:
Thyroxine is an important hormone related to growth. To study the effects of thyroxine on serum levels of insulin-like growth factor I (IGF-I), anthropometric measures, and body composition, we studied 28 patients who were receiving thyroxine therapy after thyroidectomy for well-differentiated thyroid cancer. Serum IGF-I levels decreased from 38.3 +/- 19.0 ng/ml (mean +/- SD) to 26.8 +/- 12.8 ng/ml (p <0.001) after withdrawal of thyroxine and increased to 43.8 +/- 20.2 ng/ml (p <0.001) after thyroxine was resumed. The serum levels of TSH, T3, and thyroxine changed accordingly after withdrawal and resumption of thyroxine therapy. Skinfold thickness increased from 21.8 +/- 6.5 mm to 23.7 +/- 6.4 mm (p <0.001) after withdrawal of thyroxine and decreased to 21.5 +/- 6.9 mm after resumption of thyroxine. Similar changes occurred in the circumferences of the waist and hip (p <0.01), but no significant change occurred in arm muscle circumference (18.7 +/- 2.3 cm vs 18.7 +/- 2.3 cm vs 19.0 +/- 2.4 cm). Body composition analysis by bioelectrical impedance showed no significant changes in the percentages of body fat and lean mass. In conclusion, withdrawal of thyroxine from patients with thyroid cancer was associated with an immediate decrease in serum IGF-I levels. However, lean mass did not respond to the changes in serum IGF-I levels.
Related Concept Videos
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...
Functions of Thyroid Hormones
TH is indispensable for the normal development and maturation of the skeletal, muscular, and nervous systems during fetal and childhood growth. It facilitates bone mineral turnover and regulates protein synthesis in developing tissues, contributing significantly to overall growth and...
Hyperthyroidism I: Introduction
Insulin: Dosing Regimen and Adverse Effects
The basal dose constitutes about 40%-50% of the total daily dose, with the rest as premeal insulin. The mealtime insulin dose should mirror...
Hypothyroidism II: Pathophysiology
Hyperthyroidism II: Pathophysiology