Swine Prolactin Receptor (PRLR) is a transmembrane receptor belonging to the class I cytokine receptor family, which also includes receptors for growth hormone (GHR), erythropoietin (EPOR), and several interleukins that utilize related intracellular signaling mechanisms. In pigs (Sus scrofa domesticus), PRLR binds the hormone prolactin (PRL) and activates downstream signaling pathways primarily through JAK2/STAT5, as well as MAPK and PI3K/AKT pathways, leading to regulation of genes involved in cell proliferation, differentiation, and metabolic activity. The swine prolactin receptor is expressed in multiple tissues including the mammary gland, ovary, uterus, liver, adipose tissue, and immune cells, where it mediates the physiological effects of prolactin. PRLR signaling is particularly important for mammary gland development, lactogenesis, and maintenance of milk production, supporting neonatal piglet growth and survival. It also contributes to reproductive function, maternal physiology, and metabolic regulation during pregnancy and lactation. In addition to the membrane-bound receptor, a soluble form of swine PRLR (sPRLR) can arise through alternative splicing or proteolytic cleavage, generating extracellular receptor fragments that can bind circulating prolactin and potentially modulate prolactin availability and signaling activity. Because prolactin signaling plays a key role in lactation performance, reproductive physiology, and maternal metabolism, swine PRLR and its soluble forms are studied in research on reproductive endocrinology, mammary gland biology, and genetic traits influencing sow productivity and maternal performance.