L-Thyroxine

Thyroxine (T₄) is a tetraiodo derivative of the p-hydroxyphenyl ether of tyrosine, which functions as growth factors or cell growth inhibitors. T₄ is used to treat hypothyroidism and thyroid carcinoma. It regulates energy metabolism.

L-Thyroxine has been used to investigate its role in colorectal cancer cell lines HCT 116 (APC wild type) and HT-29 (APC mutant). It has also been used to evaluate its effects on pro-inflammatory tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), angiogenic vascular endothelial growth factor (VEGF), leukocyte adhesion, intercellular adhesion molecule 1 (ICAM-1) and E-selectin in human umbilical vein endothelial cells (HUVECs).

L-Thyroxine (T₄) and triiodo-L-thyronine (T₃) are iodine-containing hormones produced from thyroglobulin in the thyroid follicular cells. The stimulation of metabolic rate and regulation of growth and development by these hormones appear to be due to their effects on DNA transcription and, thus, protein synthesis.

For long term storage, keep stock solutions at -20° in working aliquots and avoid repeated freeze/thaw cycles. Solutions stored at 2-8 °C are stable for up to 30 days.

To prepare 20 μg/ml stock solution, dissolve in 50 ml sterile culture medium per mg thyroxine.