Luteinizing hormone (LH, also known as lutropin) is a tropic hormone which modulates the secretory activity of other endocrine glands. It is produced in the anterior hypophysis of the pituitary gland. The glycoprotein hormone, LH, like follicle stimulating hormone and thyroid stimulating hormone, is composed of a common alpha-subunit but also a specific beta-subunit, which characterizes each of these hormones.