Pregnant Mare Serum Gonadotropin (PMSG) Reference: RP1782725000 PMSG is a complex glycoprotein obtained from 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. Thus PMSG-Intervet stimulates development of the ovarian follicle in the female.