GPR75 is currently classified as an orphan GPCR and several studies are underway to identify its ligand. In one study, the chemokine CCL5 (RANTES) has been shown to stimulate calcium mobilization and inositol triphosphate formation in GPR75-transfected cells.[7]
A 2021 study reported that people with protein-truncating variants of GPR75 were associated with 5.3kg lower body weight and 54% lower odds for obesity. GPR75 knock-out mice showed resistance to weight gain under high-fat diet.[8]
^"Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^"Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^Tarttelin EE, Kirschner LS, Bellingham J, Baffi J, Taymans SE, Gregory-Evans K, Csaky K, Stratakis CA, Gregory-Evans CY (June 1999). "Cloning and characterization of a novel orphan G-protein-coupled receptor localized to human chromosome 2p16". Biochemical and Biophysical Research Communications. 260 (1): 174–80. doi:10.1006/bbrc.1999.0753. PMID10381362.