Gonadotropins Serum Gonadotropin

The earliest descriptions of superovulation date back to Smith and Engle in 1927, who used crude anterior pituitary preparations to induce a fourfold increase in the ovulation rate of mice and rats A few years later, Cole and Hart demonstrated that the blood serum of pregnant mares would induce multiple ovulations in rats,[1] establishing the basis for what was to become the most widely used gonadotropin in the treatment of farm animals. This gonadotropin is commercially available in countries around the world under various trade names, e.g., Folligon (Intervet, Holland). Pregnant mare serum gonadotropin (PMSG) is a glycoprotein hormone present in the mare's circulation between days 40 and 130 of gestation and is unique as a molecule possessing both follicle-stimulating hormone (FSH) and luteinizing hor mone (LH) activity. The gonadotropin is secreted by specialized trophoblastic cells that invade the mare's endometrium between days 36 and 40. For such reasons, the term equine chorionic gonadotropin (eCG) is often used now.

The preparation was used on some scale in Soviet Russia in the 1930s and 1940s to induce mild superovulation in sheep, and it is still used by farmers in many countries for that purpose.[2] Similar attempts to use serum gonadotropin in cattle to induce twin births by inducing mild superovulation proved singularly unsuccessful.[3]

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