Description
Prolactin (PRL) or Luteotropic hormone (LTH) is best known as the pituitary modulator of lactation and reproduction (1). PRL is a multifaceted hormone that is capable of modulating hundreds of physiological processes in adult vertebrates (2). It is synthesized by the anterior pituitary, placenta, brain, uterus, dermal fibroblasts, decidua, B cells, T cells, NK cells and breast cancer cells. PRL promotes proliferation, survival and migration of cancer cells acting via the prolactin receptor (PRLR) (3). It also modulates maternal behavior and mediates hypothalamic pituitary adrenal axis inhibition during lactation via PRL receptors in the brain (4). PRL also has a number of other effects including contributing to surfactant synthesis of the fetal lungs at the end of the pregnancy and immune tolerance of the fetus by the maternal organism during pregnancy. It plays an additional immune-regulatory role by stimulating the activities of ornithine decarboxylase and protein kinase C, which are important for the proliferation, differentiation, and function of lymphocytes. PRL also decreases normal levels of sex hormones, estrogen in women and testosterone in men