Foliculin Mechanism of Action

ATC Code: G03GA04-Urofollitropin.
Pharmacology: Pharmacodynamics: Folliculin 75 I.U./150 I.U. contains purified hormone urofollitropin, obtained from Human Menopausal urine having FSH activity of 75 I.U./150 I.U. and less than 1 IU/2 IU Luteinizing Hormone activity per vial. Patients showing normal or high LH levels (WHO Group II), require preparations without LH activity, this character belongs to FSH.
FSH stimulates both the growth and maturation of follicles, it induces secretion of oestrogens and proliferation of the endometrium.
Pharmacokinetics: After multiple intramuscular dosing of Urofollitropin, the maximum plasma concentration of Follicle-stimulating hormone occurs about 10 hours after a dose, and has an elimination half-life of about 15 or 20 hours respectively.
Because there are no longer ovarian steroids and inhibition to inhibit LH and FSH secretion, gonadotropin secretion is greatly increased, and the levels of FSH are higher than those of LH in postmenopausal women.
FSH and LH are eliminated in two phases. In both phases the biological half-life of FSH is longer than that of LH.
The gonadotropins of either pituitary or placental origin are effective only if given by injection, usually intramuscularly. The rate at which gonadotropins are cleared from plasma is difficult to measure accurately because of their structural heterogeneity and the background of pulsatile secretion of the endogenous hormones.
The prolonged circulatory life of these glycoprotein hormone relative to many other peptide hormones is a result of their resistance to metabolic degradation in most tissue beds.
Clearance of injected (and presumably of endogenous) glycoprotein hormones is by glomerular filtration, followed by degradation in the proximal renal tubule or excretion (unchanged) in the urine. Removal of the sialic acid residues results in their rapid and complete clearance by the hepatic reticuloendothelial system.