Our bioactive Pregnant Mare Serum Gonadotropin (PMSG), also known as Equine Chorionic Gonadotropin (eCG), is a complex 43–63 kda native glycoprotein purified from the serum of pregnant mares. Formulation: Our PMSG is lyophilized with no additives. Application: Our PMSG and Human Chorionic Gonadotropin (hCG) are commonly used in superovulation protocols for the production of genetically modified laboratory animals (mouse, rat, Xenopus, pig), such as genetically engineered mouse models (GEMM) by pronuclear microinjection (transgenic mouse), targeted mutations through CRISPR-Cas9 methods, and embryonic stem (ES) cell-based gene targeting to produce "knockout" mice. PMSG is more likely to be used than other pituitary hormones due to the extended circulatory half-life (about 4 days in species other than horses).