**Abstract**

In this review, we will analyze the family of growth hormone (GH) genes, the territories where they are produced, the proteolytic generation of GH isoforms, both at the pituitary and tissue levels, the biological activity of these molecular forms, and we will describe the new variant GH-V2 and its effects biological. Finally, we will analyze the evolution of the hormone from its starting point with a common gene with PRL to its actions in the most evolved organisms as a true prohormone.

**Keywords:** GH gene, GH-N, GH-V, GH-V2, evolution of GH
