Human Growth hormone (HGH), also known as somatotropin, is an integral mitogen for development. It is synthesized, stored and secreted by somatotropic cells within the anterior pituitary gland (PMID 13975314). HGH stimulates growth, cell reproduction, and cell regeneration in humans and other animals (PMID 7079756). HGH stimulates both the differentiation and proliferation of myoblasts, and also stimulates amino acid uptake and protein synthesis in muscle and other tissues (PMID 8203982, 16332656).