PRL also known as Prolactin is a 226 amino acid protein, is primarily secreted by the anterior pituitary gland and plays a crucial role in numerous physiological processes, including cell growth, reproduction, and immune regulation. Notably, Prolactin is secreted by endothelial cells during angiogenesis and has been implicated in mammary cancer development, acting as both a mitogen and a differentiating agent. Prolactin enhances B cell hybridoma proliferation, significantly contributing to increased antibody production and immune responses. Additionally, Prolactin counteracts the antiproliferative effects of immunosuppressive cytokine TGF-beta, linking Prolactin to various autoimmune diseases such as arthritis and type 1 diabetes. With diverse roles in health and disease, Prolactin continues to be a vital target for research and therapeutic applications.