Gonadotropins are peptide hormones that regulate ovarian function and are essential for normal growth, sexual development and reproduction. Human gonadotropins include follicle stimulating hormone (FSH) and luteinizing hormone (LH) which are made in the pituitary, and chorionic gonadotropin (hCG) which is made by the placenta. All three gonadotropins are heterodimeric proteins that consist of two peptide chains, with the alpha chain similar in all three, whereas the beta chain is unique and determines the fine receptor specificity and function of each hormone.