ABSTRACT
Lutropin (LH) of the pituitary gland and chorionic gonadotropin (hCG) from the human placenta are two members of a family of hormones whose other members are pituitary follicle-stimulating hormone and thyroid-stimulating hormone. The ß-subunits of human LH and hCG are very closely related, although hCGß has an extension at its carboxyl terminus. The α-subunits of LH and hCG contain two asparagine N-linked oligosaccharides located at the same positions in each amino acid sequence. The amino acid sequences and structures of the oligosaccharides of LH and hCG show them to be closely related molecules and allow a rational conception of why their biological activities are so similar. Many physicochemical studies have been carried out which have yielded information concerning the overall conformation of LH and hCG and the changes in conformation that occur when α- and ß-subunits associate to form active hormone.
