Growth hormone (GH) is a protein hormone that stimulates growth and cell reproduction in humans and other animals. It is a 191-amino acid, single chain polypeptide hormone which is synthesized, stored, and secreted by the somatotroph cells within the lateral wings of the anterior pituitary gland. The hormone is also known as somatotropin (somatotrophin in British English) when referring to growth hormone produced by recombinant DNA technology, and is abbreviated "rhGH".