PTGFR is a receptor for prostaglandin F2-alpha (PGF2-alpha). PTGFR activity is mediated by G proteins that activate a phosphatidylinositol-calcium second messenger system. It has various functions in different tissues throughout the body, ranging from hair growth to reproductive signaling, hyperpigmentation of the skin, regulation of allergic response and inflammation, blood pressure control, and regulation of bone remodeling. In the corpus luteum, it initiates luteolysis. Studies in fish demonstrate that PTGFR and prostaglandin F2-alpha control the initiation of female sexual behaviour and regulate neural circuits involved with fertility status in the brain. Additionally, PTGFR is a target of agonists as part of treatment therapies for various diseases including glaucoma, hypotrichosis of the eyelashes, and periorbital vitiligo or hypopigmentation of the skin. In immunohistochemistry, PTGFR has membranous positivity in the uterine myometrium, in smooth muscle cells and the endothelium in the eye, as well as distal tubules of the kidney and luteal cells of the corpus luteum in the ovaries. References: Curr Biol. 2016 Apr 4;26(7):943-9, PMID: 26996507; American Academy of Dermatology. 2015. 72 (4): 712–6, PMID: 25601618; Prostaglandins & Other Lipid Mediators. 2013. 104–105: 109–21, PMID: 23353557;