Mouse and Rat Transforming Growth Factor Alpha (TGF-α) is a member of the epidermal growth factor (EGF) family of growth factors, which also includes epidermal growth factor (EGF), amphiregulin, betacellulin, epiregulin, and heparin-binding EGF-like growth factor (HB-EGF). In both mice (Mus musculus) and rats (Rattus norvegicus), the mature TGF-α protein is identical at the amino acid level, reflecting strong evolutionary conservation and indicating similar biological functions in these rodent species. TGF-α is synthesized as a membrane-bound precursor (pro–TGF-α) that undergoes proteolytic cleavage to release a soluble ligand capable of binding the epidermal growth factor receptor (EGFR/ErbB1). Activation of EGFR stimulates intracellular signaling pathways including MAPK/ERK, PI3K/AKT, and JAK/STAT, which regulate cell proliferation, epithelial growth, differentiation, and tissue repair. In mice and rats, TGF-α is expressed in tissues such as the skin, gastrointestinal tract, liver, brain, and reproductive organs, where it contributes to epithelial cell turnover, organ development, and regeneration following tissue injury. TGF-α signaling has been widely studied in rodent models of wound healing, liver regeneration, and cancer, where dysregulated EGFR signaling can promote tumor development and epithelial hyperproliferation. Because mice and rats are among the most widely used experimental organisms in biomedical research, characterization of TGF-α in these species has been fundamental for understanding EGFR-mediated growth signaling, epithelial biology, and mechanisms of tissue regeneration and oncogenesis relevant to human disease.