Gonadotropin-releasing hormone (GnRH), also known as luteinizing hormone-releasing hormone (LHRH), is a peptide hormone responsible for the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary. GnRH is commonly prescribed for increasing libido in stallions, cryptorchid testing, endocrine function testing and ovarian tumor testing.