This invention relates to the field of glycoprotein hormone analogs and their uses as agonists, antagonists, targeting vectors, and immunogens. In particular, this invention describes a method for stabilizing a heterodimer that permits the preparation of functional glycoprotein hormone analogs. The analogs of present invention comprise at least one alpha subunit polypeptide and at least one beta subunit polypeptide, wherein the seatbelt region of the beta subunit is linked to the alpha subunit. The invention also provides for a beta subunit polypeptide wherein the C-terminal amino acid is from residue 10 to residue 20 of the seatbelt region.
