Pharmacological properties : תכונות פרמקולוגיות

Pharmacodynamic Properties

12.1   Mechanism of Action
Thyrotropin (TSH) is a pituitary hormone that stimulates the thyroid gland to produce thyroid hormone. Binding of thyrotropin alfa to TSH receptors on normal thyroid epithelial cells or on well-differentiated thyroid cancer tissue stimulates iodine uptake and organification, and synthesis and secretion of thyroglobulin (Tg), triiodothyronine (T3) and thyroxine (T4).
The effect of thyroid stimulating hormone activation of thyroid cells is to increase uptake of radioiodine to allow scan detection or radioiodine killing of thyroid cells.
TSH activation also leads to the release of thyroglobulin by thyroid cells. Thyroglobulin functions as a tumor marker which is detected in blood specimens.

Pharmacokinetic Properties

12.3   Pharmacokinetics
The pharmacokinetics of THYROGEN was studied in 16 patients with well- differentiated thyroid cancer given a single 0.9 mg IM dose. Mean peak serum TSH concentrations of 116±38 mU/L were reached between 3 and 24 hours after injection (median of 10 hours). The mean apparent elimination half-life was 25±10 hours. The organ(s) of TSH clearance in man have not been identified, but studies of pituitary- derived TSH suggest the involvement of the liver and kidneys.