PMSG is a complex glycoprotein obtained the serum of pregnant mares. This 43-63 kda protein is capable of supplementing and being substituted for the follicle stimulating gonadotrophin and interstitial cell-stimulating hormone of the anterior pituitary gland in both the male and female.-PMSG is a complex glycoprotein obtained　the serum of pregnant mares. This 43-63 kda protein is capable of supplementing and being substituted for the follicle stimulating gonadotrophin and interstitial cell-stimulating hormone of the anterior pituitary gland in both the male and female.