What are LHRH agonists, and how do they work?
LHRH agonists are synthetic analogs of the normal human hormone luteinizing hormone-releasing hormone, which is produced in the human hypothalamus and stimulates the production of a second hormone known as luteinizing hormone (LH). It is luteinizing hormone which subsequently stimulates the production of testosterone in men. All LHRH agonists are small synthetic proteins which are structurally similar to normal human LHRH. However, they are much more powerful than the normal form. When a man with prostate cancer is first given an LHRH agonist injection, it has several effects: • First, it stimulates production of luteinizing hormone, which stimulates production of testosterone, which means that for a couple of weeks the patient’s testosterone level will usually rise instead of falling. The increase in the patient’s testosterone level can stimulate briefly increased growth of prostate and prostate cancer cells, with such associated symptoms as increased bone pain, if the patient already
