Lutropin alfa is a recombinant human luteinizing hormone produced in yeast with 2 subunits, alpha = 92 residues, beta = 121 residues. It is a heterodimeric glycoprotein. Each monomeric unit is a glycoprotein molecule. In females, an acute rise of LH (“LH surge”) triggers ovulation and the development of the corpus luteum. In males, it stimulates Leydig cell production of testosterone. Lutropin alfa was the first and only recombinant human form of luteinizing hormone (LH) developed for use in the stimulation of follicular development.