Triptorelin is a synthetic luteinizing hormone releasing hormone (LHRH) analog. Like naturally occurring LHRH that is produced by the hypothalamus, initial or intermittent administration of triptorelin stimulates release of gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), from the anterior pituitary. Long-term, sustained use of triptorelin is associated with an early phase of increased LH and FSH levels, followed by their suppression.
In males, the release of LH and FSH results in a transient increase in testosterone concentrations. However, monthly administration of triptorelin in the treatment of prostatic carcinoma suppresses secretion of LH and FSH, with a resultant fall in testosterone concentrations and a pharmacologic castration within 4 weeks following initial administration.