Pharmacology: Leuprorelin is a synthetic nonapeptide analogue of natural Gn-RH. The studies performed in humans as well as in animals have demonstrated that, after an initial stimulation, the prolonged administration of leuprorelin induces a decrease of gonadotropin secretion, consequently suppressing the testicular function in men and inducing an atrophy of the uterine and ectopic endometrial tissue in women. This effect is reversible upon discontinuation of drug therapy.
Through some studies in animals, another mechanism of action has been evoked: A direct effect by the decrease of sensitivity of the gonadotropin receptors.
In humans, after administration of the 1st dose, an increase in circulating levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) is induced, leading to an initial increase in levels of the gonadal steroids (testosterone and dihydrotestosterone in men, and oestradiol in women). The pursuit of the treatment leads to a decrease in LH and FSH levels, inducing within 3-4 weeks, to androgen or oestrogen levels equivalent to those obtained after castration or menopause, as long as drug administration continues.