Stimulates the ovaries to synthesize the steroids that are essential for the maintenance of pregnancy. Heterodimer of a common alpha chain and a unique beta chain which confers biological specificity to thyrotropin, lutropin, follitropin and gonadotropin. Placenta. There are at least five copies of CG-related genes and at least two of these are expressed in the baboon placenta. Belongs to the glycoprotein hormones subunit beta family.