Bovine somatotropin (abbreviated bST and BST), or BGH, is a peptide hormone produced by the cow's pituitary gland. Like other hormones, it is produced in small quantities and is used in regulating metabolic processes. After the biotech company Genentech discovered and patented the gene for BST in the 1970s, it became possible to synthesize the hormone using recombinant DNA technology to create recombinant bovine somatotropin (rBST), recombinant bovine growth hormone (rBGH), or artificial growth hormone. Four large pharmaceutical companies, Monsanto, American Cyanamid, Eli Lilly, and Upjohn, raced to develop commercial rBST products and submitted them to the FDA for approval. Worldwide, Lilly was first to market with sales in Mexico, Brazil and other countries that have approved their BST products for commercial sale. Monsanto licensed Genentech's patent, and was first to get FDA approval, and marketed their product as "Posilac". In October 2008, Monsanto sold this business, in full, to Lilly for a price of $300 million plus additional consideration.
rBST has not been allowed on the market in Canada, Australia, New Zealand, Japan, Israel and all European Union countries (currently numbering 27), by 2000 or earlier.
In the United States, public opinion has caused a number of products and retailers to become rBST-free.
Read more about Bovine Somatotropin: History, Controversy, Regulation, Response From Commercial Groups